Facial botulinum toxin injections in Paris : relax the muscle without freezing the expression
What botulinum toxin does to the muscle, what it doesn't do to the skin — and why the result depends on facial expression analysis far more than the injected product.
Written and validated by Dr Nathaniel Stroumza-Escoffier , qualified plastic surgeon in plastic, reconstructive and aesthetic surgery — RPPS 10100674943. Last medical review: August 2026.
Facial botulinum toxin injections are a medical procedure that temporarily relaxes the muscles responsible for expression lines—frown lines, forehead wrinkles, and crow's feet. Dr. Nathaniel Stroumza-Escoffier, a plastic surgeon practicing at 11 rue du Faubourg Saint-Honoré in the 8th arrondissement of Paris, has been performing this procedure for fifteen years and carries out 300 to 400 sessions annually, using a modulation rather than blocking approach: softening the wrinkle without erasing the expression. This requires tailoring the injections to each individual's facial expressions, rather than following a standard protocol.
Botulinum toxin injection in one minute
Nature of the act | Medical procedure. In France, prescriptions for cosmetic purposes are reserved for five specialties. |
Product status | This is a medication that requires a medical prescription — and not a medical device. |
Molecule | Botulinum toxin type A: purified protein produced by the bacterium Clostridium botulinum. |
Mechanism | Blocking of acetylcholine release at the neuromuscular junction, by cleavage of the SNAP-25 protein. |
Effect | Temporary relaxation of the injected muscle. The skin is not directly altered. |
Upper third | Frown lines (glabella), forehead wrinkles, crow's feet. 75% of sessions performed in the office. |
lower third | Masseters, gummy smile, commissure depressors, lip flip, neck bands (Nefertiti lift). |
Hyperhidrosis | Armpits, palms of hands, soles of feet. |
Anesthesia | None. Very fine needle; application of cold possible. |
Technical | Microinjections with a 34G needle, 0,01 to 0,05 mL per point. |
Session duration | 10 to 15 minutes. |
Action time limit | Initial effects in 3 to 7 days; full effect around day 15. |
Duration of effect | 4 to 6 months. |
Social exclusion | None. Bruising may occur for 3 to 7 days. |
Frequency | 3 to 6 months between two sessions. |
Reversibility | No. There is no antidote — but the effect disappears spontaneously. |
Adverse reactions | Bruising, transient headache. Eyelid ptosis in 0,7% of treatments. |
Contraindications | Myasthenia gravis and neuromuscular junction disorders, pregnancy, breastfeeding, site infection. |
Prices | Upper third €400 · Full treatment €600. Consultation free of charge, touch-up included within 15 days. No reimbursement for cosmetic indications. |
REMEMBER IN 30 SECONDS Botulinum toxin acts on the muscle, not on the skin: it treats expression lines, not wrinkles caused by sagging skin or skin quality. Mechanism: temporary blockage of acetylcholine release by cleavage of the SNAP-25 protein — a chemical denervation, reversible by construction. Transient effect: 4 to 6 months. There is no antidote, but the effect disappears on its own. Status: prescription-only medicine. In France, prescriptions for cosmetic purposes are reserved for five medical specialties, including plastic, reconstructive and cosmetic surgery. The approach to the practice is to modulate rather than block. Maintaining facial expressions is the criterion for a successful result. Complementary treatment: the toxin addresses movement; hyaluronic acid addresses volume and skin quality. Both can be performed during the same session. |
SHORT ANSWER According to Dr. Nathaniel Stroumza-Escoffier, a plastic surgeon in Paris, botulinum toxin type A temporarily relaxes the muscles that cause facial expressions to crease. It treats expression lines—frown lines, forehead wrinkles, crow's feet—and not wrinkles caused by sagging skin or skin quality. The effect appears in 3 to 7 days, is complete around the fifteenth day, and lasts 4 to 6 months. The dose and injection points are determined by analyzing facial expressions, not by a standard protocol. |
DEFINITION Botulinum toxin type A : a purified protein produced by Clostridium botulinum, used in medicine in infinitesimal doses. Neuromuscular junction : the point of contact between a nerve and a muscle, where the nerve releases acetylcholine, which controls muscle contraction. SNAP-25 : a protein necessary for this release; it is this protein that the toxin cleaves. Expression line : a wrinkle visible during muscle contraction. Resting line : a wrinkle that remains visible when the face is relaxed, also known as an "imprinted" line. Unit (IU) : a measure of biological activity specific to each pharmaceutical product and not transferable from one product to another. Chemodenervation : the temporary interruption of nerve control of a muscle by a chemical agent. |
Since the first series was published in 1992, botulinum toxin has become the most frequently performed cosmetic procedure in the world. This widespread use has a downside: it has led to the forgetting that it is a medication, that its administration relies on precise functional anatomy, and that most disappointing results stem not from the product itself, but from the dose and injection site chosen.
This article explains what botulinum toxin actually does in the muscle, what the scientific literature establishes, which wrinkles it treats and which it does not treat, with what doses, what its real risks are, and what regulatory framework governs its prescription in France — a point on which there is great confusion and serious consequences.
What is botulinum toxin and how does it work?
Botulinum toxin is a protein that temporarily prevents the nerve from transmitting the signal to the muscle to contract. The injected muscle relaxes, the overlying skin stops wrinkling, and the expression line diminishes. The toxin does not act on the skin itself.
Botulinum toxin type A is produced by the bacterium Clostridium botulinum, which causes botulism. In medicine, it is purified, titrated, and administered in doses far exceeding those used in cases of food poisoning, locally and never systemically. This difference in scale and route of administration explains why the same agent can be both a formidable toxin and a medication whose safety has been documented for over thirty years.
Its mechanism is now precisely described. When a nerve signals a muscle, it releases a neurotransmitter, acetylcholine, at their point of contact—the neuromuscular junction. This release requires a set of proteins that allow the vesicles containing acetylcholine to fuse with the nerve membrane. Botulinum toxin type A acts as an enzyme that selectively cleaves one of these proteins, called SNAP-25. Without intact SNAP-25, the vesicle no longer fuses, acetylcholine is no longer released, and the muscle no longer receives the signal to contract.
This blockade is targeted: it only affects the muscle fibers located in the immediate vicinity of the injection point. This is why needle placement is just as important as the amount injected.
Why does the effect disappear after a few months?
Because the neuromuscular junction repairs itself. The nerve sends new nerve endings to the muscle, and the SNAP-25 protein is renewed: transmission gradually returns, and contraction becomes normal again. This reversibility is not a flaw in the treatment; it is its fundamental property—and the reason why there is no antidote. The effect cannot be reversed; one can only wait for it to wear off, which takes four to six months.
This reversibility has an important practical consequence: an unsatisfactory result will not last. This is a major difference from surgery, and a notable difference from dermal fillers, which are dissolved by an enzyme.
In short — According to Dr. Stroumza-Escoffier, botulinum toxin type A blocks the release of acetylcholine at the neuromuscular junction by cleaving the SNAP-25 protein. The injected muscle relaxes for 4 to 6 months, then the junction repairs itself and contraction returns to normal. There is no antidote: the effect disappears spontaneously.
Figure 1 — Mechanism of action of botulinum toxin at the neuromuscular junction. The toxin binds to the nerve ending, is internalized by endocytosis, then its light chain crosses the endosomal membrane and cleaves the SNAP-25 protein. The SNARE complex can no longer form: the acetylcholine vesicles do not fuse with the presynaptic membrane, and the muscle no longer receives the signal to contract. Diagram created by Dr. Nathaniel Stroumza-Escoffier. This is a teaching aid and not a medical image; the two faces in the "effect on muscle" section are illustrations and not clinical photographs.
What does the scientific literature say?
Four elements are firmly established: the molecular mechanism, the effectiveness on frown lines in placebo-controlled trials, the absence of serious adverse effects in meta-analyses, and the absence of risk accumulation when repeating sessions.
Data | Result | Source |
|---|---|---|
Origin of aesthetic use | First published series: 18 patients treated for glabellar lines, improvement observed in 16 of the 17 followed, for durations of 3 to 11 months. Minimal and transient side effects. | Carruthers JD & Carruthers JA, J Dermatol Surg Oncol, 1992 — PMID 1740562 |
Molecular mechanism | Botulinum toxin type A acts as a zinc-dependent protease that selectively cleaves the synaptic protein SNAP-25, thereby blocking the release of the neurotransmitter. | Blasi J et al., Nature, 1993 — PMID 8103915 |
Efficacy (randomized placebo-controlled trial) | 273 patients, 20 units distributed across five sites. Maximum response rate at day 30: 77% according to physician assessment and 89% according to patient assessment, significantly higher than placebo at each visit. Eyelid ptosis: 1%. | Carruthers JD et al., Plast Reconstr Surg, 2003 — PMID 12973229 |
Overall tolerance | Meta-analysis of 36 randomized trials, 2,309 subjects, including 1,425 treated. No serious adverse events reported. Mild to moderate adverse events: approximately 25% versus 15% with placebo. Only localized muscle weakness was significantly more frequent than with placebo. | Naumann M & Jankovic J, Curr Med Res Opin, 2004 — PMID 15265242 |
Safety of repeated treatments | 1,415 patients were followed for up to 36 months, with an average of 5,6 sessions. The rate of adverse effects did not increase with repeated cycles. Eyelid ptosis was observed after 53 of the 7,938 treatments (0,7%), all resolving spontaneously. | Schlessinger J et al., Dermatol Surg, 2014 — PMID 24372978 |
Secondary resistance | Neutralizing antibodies can reduce or negate the effect of the treatment. Identified contributing factors include: excessively short intervals between sessions, high doses per cycle, and the amount of antigenic protein in the product. | Bellows S & Jankovic J, Toxins, 2019 — PMID 31454941 |
These data are derived from studies conducted with specific pharmaceutical products, whose dosage units are not interchangeable. They establish a mechanism of action, efficacy, and safety profile; they do not predict individual results. Full references are at the end of the article.
In short — Indexed literature establishes that botulinum toxin type A cleaves the SNAP-25 protein and blocks neuromuscular transmission, that it significantly reduces frown lines in controlled trials, that no serious adverse effects were reported in a meta-analysis of 36 trials, and that repeating sessions does not increase the rate of adverse effects.
Which wrinkles does botulinum toxin treat?
It treats expression lines, that is, those that appear during muscle contraction: frown lines, forehead wrinkles, crow's feet. It does not treat wrinkles due to volume loss, skin quality, or established skin laxity.
The key distinction is between expression lines and resting wrinkles. The former only appears when the muscle contracts: this is the primary indication. The latter remains visible even with a relaxed face because the crease has gradually become imprinted in the dermis. On a resting wrinkle, the toxin reduces the dynamic component and prevents it from worsening, but it doesn't erase the existing crease: a second treatment is often necessary.
At Dr. Stroumza-Escoffier's practice, the upper third of the face accounts for approximately 75% of the sessions. The remaining 25% are divided between treatments for the lower third of the face and the neck, and the treatment of hyperhidrosis.
Areas | Muscle involved | Desired effect | Point of vigilance |
|---|---|---|---|
Lion's wrinkles (glabella) | Corrugators and procerus | Softening of the vertical crease between the eyebrows, opening of the eyes, elimination of a stern expression | The best-documented area. Diffusion towards the levator palpebrae superioris muscle exposes to palpebral ptosis. |
Forehead wrinkles | Frontal muscle | Softening of horizontal lines | The frontal bone is the only eyebrow lifter. Over-treating it causes the tail of the eyebrow to droop and weighs down the look: the doses used are deliberately measured. |
Crow's feet | Orbicularis oculi, lateral portion | Reduction of smile lines at the corner of the eye | Superficial injection, away from the orbital rim. |
Nose wrinkles | Transverse nasal muscle | Reduction of oblique folds at the root of the nose | Often increased after treatment of the glabella, due to delayed contraction. |
Gummy smile | Levator labii superioris and alaeque nasi | Lowering of the upper lip when smiling, reduction of gum exposure | Very low doses, precise points. Asymmetry is possible and requires monitoring. |
Lip flip | Orbicularis oris, upper portion | Subtle eversion of the upper lip edge, without adding volume | Minimal doses. Temporary difficulty speaking or drinking through a straw is possible. |
Drooping corners of the mouth | Commissure depressors (DAO) | A discreet lifting of the corners of the mouth, correcting the sad expression at rest | Very low doses and strictly placed: diffusion towards neighboring muscles alters the smile. |
Chin relief | Mental muscle | Smoothing the grainy appearance of the chin and softening the chin crease |
|
Vertical neck bands (Nefertiti lift) | Platysma | Reduction of visible cords during contraction and redefinition of the mandibular line | Limited indication: does not correct established cervical skin laxity. Transient dysphagia is rare. |
Masseters | Masseter muscle | Refinement of the lower third of the face, reduction of jaw clenching | Gradual effect over several months, maintenance required. Indication shared with bruxism. |
Hyperhidrosis | Sweat glands (armpits, palms, soles) | Lasting reduction of excessive sweating | The blockage here involves the control of the glands, not a muscle. A transient weakness in grip strength is possible in the palms. |
What botulinum toxin does not treat
- A loss of volume. Hollowing of the temples, cheeks or under-eye circles is due to filling, not muscle relaxation.
- Skin quality. Dull complexion, uneven texture, dehydration, loss of density: the toxin has no effect on these parameters. They are addressed by skin boosters, vitamin therapy, or collagen inducers.
- A persistent loss of skin elasticity. No injection can lift tissue that is sagging. When sagging of the neck and lower face becomes the dominant feature, the question that arises is surgical.
- A deep and isolated resting ridge. The toxin prevents it from worsening, but erasing the already imprinted furrow requires a second step.
Suggested internal links: anchor "hyaluronic acid injection" → /aesthetic-medicine/hyaluronic-acid-injection/ | anchor "skinboosters" → /aesthetic-medicine/skinboosters/ | anchor "SNEC Lift" → /techniques/snec-lift/
In short — Botulinum toxin treats expression lines in the upper third of the face — frown lines, forehead lines, crow's feet — which account for 75% of sessions, as well as targeted areas in the lower third and neck: masseter muscles, gummy smile, lip flip, depressor gingiva, platysma bands. It does not treat volume loss, skin quality, or established skin laxity.
Does botulinum toxin have any medical indications?
Yes, and they predate its cosmetic use. Botulinum toxin has been used since the 1980s in neurology and ophthalmology, and has marketing authorizations for several conditions where excessive muscle contraction is involved.
Examples include blepharospasm, spasmodic torticollis, spasticity in adults and children, overactive bladder, and chronic migraine. Two conditions are of particular interest to the practice. Hyperhidrosis—excessive sweating of the armpits, palms, or soles, resistant to topical treatments—in which the toxin blocks not a muscle but the control of the sweat glands, which is mediated by the same neurotransmitter. And bruxism, or nocturnal jaw clenching, which straddles the line between functional and aesthetic concerns, as the gesture simultaneously slims the lower third of the face.
This dual nature has a regulatory consequence that is often overlooked: in France, any doctor can prescribe botulinum toxin for therapeutic purposes, whereas its prescription for cosmetic purposes is restricted to five specialties. The product is the same; the regulatory framework is not.
How are the dose and injection sites chosen?
Based on the analysis of facial expressions in motion, never on a standard protocol. Two faces with the same wrinkle at rest may require very different doses and injection points, depending on the strength of the muscle, the position of the eyebrow, and the balance between elevator and depressor muscles.
The consultation includes a dynamic examination: the patient frowns, raises their eyebrows, smiles, and squints. This examination provides information on four parameters that determine the prescription — the strength of contraction of each muscle group, the height and shape of the eyebrow at rest and when raised, the existence of a pre-existing asymmetry, and the respective contribution of the dynamic component and the imprinted component in each wrinkle.
What the examination shows | Preferred response | Rhythm |
|---|---|---|
The wrinkle is only visible when contracted. | Botulinum toxin alone | Single session, result judged on the 15th day |
A wrinkle visible at rest, already imprinted | Botulinum toxin, followed by discussion of a filler procedure as a second step | Toxin test first, reassessment in 4 to 6 weeks |
Eyebrow already low, upper eyelid heavy | Treatment of the forehead is reduced or delayed; priority is given to the glabella. | Reassessment before any additional steps |
Pre-existing facial asymmetry | Asymmetrical doses, documented before the procedure | 15-day check-up |
Loss of volume or altered skin quality | Hyaluronic acid, skinboosters, collagen inducers | See the page dedicated to hyaluronic acid injections |
Established skin laxity of the neck or lower face | No injection corrects it: surgical discussion | Dedicated consultation |
Example of protocol and administered doses
The doses below correspond to a protocol as applied in the office to an adult patient presenting with moderate facial expression. They are provided for educational purposes only: they do not constitute a prescription or a reproducible protocol.
Figure 2 — Mapping of botulinum toxin injection sites, number of points and doses per site. Upper third: forehead, glabella, tail of the eyebrow, crow's feet. Middle third: bunny lines, gummy smile, lip flip. Lower third: masseter muscles, depressor commissors, chin. Neck: platysmal bands. Diagram created by Dr. Nathaniel Stroumza-Escoffier. The values shown are those used in the practice and are expressed in the units of the specific botulinum toxin used there: they are not applicable to any other product.
READ BEFORE THE TABLES — WHY THESE FIGURES ARE NOT TRANSFERABLE Botulinum toxin doses are expressed in units. A unit is not a quantity of product: it is a measure of biological activity, defined by a test specific to each manufacturer. Therefore, the units of one product do not correspond to those of another, and there is no official conversion factor to convert between them. A number of units found on a website is therefore meaningless until you know which product it refers to. The values presented below are those used in the practice with the specific product used there. Furthermore, for the same product, these values vary depending on muscle strength, sex, tissue thickness, the desired outcome, and previous treatments. These details are published for informational and transparency purposes, and not for reproduction. Your specific dose will be determined during a consultation, after examination. |
Upper third of the face
Areas | Muscle | Indicative dose |
|---|---|---|
Frown lines | Corrugators and procerus | 20 IU |
Forehead wrinkles | Frontal muscle | 20 IU |
Crow's feet | Orbicularis oculi | 12 IU per side, i.e. 24 IU |
Total — glabella, forehead and crow's feet |
| 64 IU |
Eyebrow tail elevation | Orbicularis oculi, superior lateral portion | 2 to 4 units per side |
Middle third, lower third and neck
Areas | Muscle | Indicative dose |
|---|---|---|
Rabbit lines | Transverse nasal muscle | 1 to 2 IU per point, 2 to 4 IU in total |
Gummy smile | Levator labii superioris and alaeque nasi | 10 IU per side, i.e. 20 IU |
Lip flip | Orbicularis oris | 4 IU per side, i.e. 8 IU |
Drooping corners of the mouth | commissure depressors | 2 IU per side, i.e. 4 IU |
Chin relief | Mental muscle | 3 to 10 IU in total |
Masseters | Masseter muscle | 25 IU per side, i.e. 50 IU |
Neck bands (Nefertiti lift) | Platysma | 20 IU per side, i.e. 40 IU |
Two orders of magnitude emerge from these tables, and they are instructive. The first is the considerable difference between the zones: four units are enough to correct a drooping corner of the mouth, whereas the masseter muscle requires fifty. This is not a question of the size of the zone, but of muscle mass and function. The second is that the lowest doses are the most technically demanding: on the corner depressors of the mouth or on the lip, two misplaced units produce an asymmetrical smile, while the same difference would go unnoticed on a masseter muscle.
A word about a predictable objection. Publishing dosages on a public website might seem contradictory to the warning against illegal injectors found later in this article. It isn't: these values are found in medical literature and in product information summaries, and they are accessible to any practitioner. What an illegal injector lacks has never been the number itself, but rather the qualification to determine the indication, knowledge of the anatomy that determines the injection site, asepsis, product traceability, and the ability to manage complications. Publishing the dosage teaches nothing to those who shouldn't be injecting; however, it allows a patient to understand what is being offered to them.
In short — In the office, a complete treatment of the upper third of the face requires 64 units: 20 for the glabella, 20 for the forehead, and 12 per side for crow's feet. The masseter muscles require 25 units per side, the platysma 20, the gummy smile 10, the lip flip 4, and the commissural depressors 2. These units are specific to a given pharmaceutical specialty and cannot be applied to any other.
The LIFT UP protocol
When several factors are present in the same patient—which is most often the case after age forty—Dr. Stroumza-Escoffier combines approaches within a protocol he named LIFT UP, structured in four steps: a volumizing hyaluronic acid to restore lost support, a hydration booster for skin quality, a biostimulator for firmness, and botulinum toxin for expression lines. Each step corresponds to a distinct anatomical plan: it is their combination, and not increasing the dosage of any one of them, that produces the result.
These procedures can be performed during the same session. Botulinum toxin, hyaluronic acid, and skin boosters do not act in the same way or through the same mechanism, and combining them does not increase the after-effects or risks—on the contrary, it saves the patient from having to make multiple appointments. The order of the procedures within the session follows a precise logic, which will be the subject of a dedicated article.
Data from Dr. Stroumza-Escoffier's practice
Dr. Nathaniel Stroumza-Escoffier has been performing botulinum toxin injections for fifteen years and carries out between 300 and 400 sessions per year. A qualified plastic surgeon, he belongs to one of the five specialties authorized in France to prescribe botulinum toxin for cosmetic purposes.
Parameter | Data | What this means for the patient |
|---|---|---|
Qualification | Plastic, Reconstructive and Aesthetic Surgery — RPPS 10100674943 | The practitioner falls within the regulatory scope of prescribing botulinum toxin for aesthetic purposes. |
Decline in practice | 15 years of botulinum toxin injections | This practice is old enough to have observed the long-term outcomes of patients treated regularly. |
Annual volume | 300 to 400 sessions per year | Regular practice is essential for precision of movement and management of adverse effects. |
Distribution of indications | 75% upper third of the face · 25% lower third, neck and hyperhidrosis | The majority of requests relate to expression lines around the eyes and forehead. |
Patient profile | 70% with regular maintenance · 30% having never been injected | A majority of patients are followed over time, which allows for adjusting the doses from one session to the next. |
Dosage approach | Doses adjusted according to facial expression, never maximal on the upper third | The stated objective is to maintain an expression, not to obtain a static forehead. |
Tracking | Remote validation of the result based on photographs and videos submitted by the patient. Follow-up consultation 15 days later in case of persistent wrinkles or asymmetry, including touch-up. | The patient does not have to travel if the result is satisfactory, but the check-up remains open and free of charge if it is not. |
Transmission | More than 100 trained doctors — 80 cosmetic doctors and 30 surgeons, in France and internationally | A practice that is taught, and therefore subject to criticism from peers. A list of names is kept. |
Learned Society | Member of the SOFCEP scientific committee | Participation in the scientific evaluation of practices in the specialty. |
This data describes the conditions under which it was carried out and the volume of activity. It does not prejudge any individual results.
In short — Dr. Stroumza-Escoffier has been performing botulinum toxin injections for fifteen years and carries out 300 to 400 sessions per year, 75% of which target the upper third of the face. Seven out of ten patients undergo regular maintenance follow-up appointments. The result is validated remotely using photographs and videos, with a follow-up consultation 15 days later, including any necessary touch-ups.
Clinical cases: before and after results
The three cases below document treatments performed at Dr. Nathaniel Stroumza-Escoffier's office: forehead wrinkles and frown lines in a 40-year-old patient, crow's feet in a 48-year-old patient, and a gummy smile in a 25-year-old patient. The images were taken in contraction, the only situation in which an expression line is visible.
Method and limitations of these photographs These images have not undergone any local retouching: no smoothing, no shape modification, no contour correction, and no color alteration. Only two treatments were applied, identical for the before and after of each case: resizing to the same scale, and the application of an opaque dot over the pupils for anonymization. No areas treated with botulinum toxin are masked. These images are published with the patients' written consent. Three limitations must be understood. The intensity of voluntary facial contraction is not perfectly reproducible from one photograph to another: a frown or a smile cannot be controlled with the same precision as a static pose. Lighting, shooting distance, and head position are not exactly the same before and after. Finally, clothing and hairstyle differ from one photograph to another, which alters the perception of the face independently of any processing. An individual result cannot be deduced from these images: it depends on each person's anatomy, muscle strength, and facial expressions. |
Case 1 — 40-year-old patient: forehead wrinkles and frown lines
Treatment of the upper third of the body, including the frontalis muscle and glabellar complex, according to the protocol described above: 20 units on the glabella and 20 units on the forehead. Both sets of images are taken with voluntary contraction—maximum eyebrow elevation for the forehead, frowning for the glabella.
Figure 3 — Forehead wrinkles, maximum eyebrow elevation. Before treatment, the horizontal lines of the forehead are marked when the muscles contract. After treatment, they are softened while eyebrow elevation remains possible: this is the desired outcome, as the mobility of the frontalis muscle is preserved rather than eliminated.
Figure 4 — Frown lines, voluntary frown. Before treatment, the vertical crease between the eyebrows and the downward slope of the brow head give a stern appearance both at rest and when contracted. After treatment, the frown no longer deepens the glabellar fold, and the position of the brow head is restored.
Case 2 — 48-year-old female patient: crow's feet
Treatment of the lateral portion of the orbicularis oculi muscle, 12 units per side. The images are taken while smiling, the only situation in which crow's feet wrinkles are visible. The injection is superficial and kept away from the orbital rim.
Case 3 — 25-year-old female patient: gummy smile
Treatment of the levator muscles of the upper lip and ala of the nose, 10 units per side. The aim is to slightly lower the upper lip when smiling, in order to reduce gum exposure, without altering the volume or shape of the lip.
Figure 6 — Gummy smile, voluntary smile viewed from the front. Before treatment, the elevation of the upper lip largely exposes the gum. After treatment, the upper lip covers the necks of the teeth, and gingival exposure is reduced. Since the extent of the smile is not exactly the same from one photograph to another, the comparison should be interpreted with caution.
Botulinum toxin or hyaluronic acid: which to choose?
The two products do not treat the same thing and are not subject to the same legal status. Botulinum toxin acts on the muscle and treats movement. Hyaluronic acid acts on the dermis and restores volume. They are complementary and are frequently used together in the same session.
Criterion | Botulinum toxin | Hyaluronic acid |
|---|---|---|
Product status | Prescription-only medication | Injectable medical device |
Target | The muscle | The dermis and volumes |
Typical indication | Frown lines, forehead wrinkles, crow's feet | Skin quality, dark circles, temples, cheeks, wrinkles |
Action time limit | 3 to 15 days. | Immediate for filling, gradual for regeneration |
Duration | 4 to 6 months | 6 to 18 months for the filling |
Reversibility | No, but a temporary effect | Yes, by hyaluronidase |
Who can inject it into France? | Five medical specialties | Every doctor |
The choice is therefore almost never framed in those terms. The relevant question is not "toxin or hyaluronic acid," but "what is producing what I see in the mirror": movement, a lack of volume, less dense skin, or sagging tissue. Each of these answers corresponds to a different tool, and often several.
Botulinum toxin or hyaluronic acid: which to choose?
The two products do not treat the same thing and are not subject to the same legal status. Botulinum toxin acts on the muscle and treats movement. Hyaluronic acid acts on the dermis and restores volume. They are complementary and are frequently used together in the same session.
Criterion | Botulinum toxin | Hyaluronic acid |
|---|---|---|
Product status | Prescription-only medication | Injectable medical device |
Target | The muscle | The dermis and volumes |
Typical indication | Frown lines, forehead wrinkles, crow's feet | Skin quality, dark circles, temples, cheeks, wrinkles |
Action time limit | 3 to 15 days. | Immediate for filling, gradual for regeneration |
Duration | 4 to 6 months | 6 to 18 months for the filling |
Reversibility | No, but a temporary effect | Yes, by hyaluronidase |
Who can inject it into France? | Five medical specialties | Every doctor |
The choice is therefore almost never framed in those terms. The relevant question is not "toxin or hyaluronic acid," but "what is producing what I see in the mirror": movement, a lack of volume, less dense skin, or sagging tissue. Each of these answers corresponds to a different tool, and often several.
Can we start early? The question of the so-called preventative toxin
The recommendation is based on the examination, not on age. The preventive reasoning is mechanically sound — a wrinkle that doesn't deepen doesn't leave an imprint — but its level of evidence remains low, and it must be presented as such.
The demand for early treatment, often made between the ages of twenty-five and thirty-five, is based on a simple idea: resting wrinkles arise from the repetition of dynamic creases, so reducing contraction would delay their appearance in the dermis. This reasoning is plausible and consistent with what is known about the mechanism.
However, the published data supporting this hypothesis remain limited. The most frequently cited studies are two observations of monozygotic twins, one of whom received regular treatment for thirteen and then nineteen years, while the other did not: the forehead and glabellar lines visible at rest were absent in the treated twin. This is a striking observation, but these are reported cases, not controlled trials: the level of evidence is low, and no general conclusions can be drawn with certainty.
The practitioner's opinion: Treating a young patient whose facial expressions leave no trace at rest amounts to initiating chronic treatment without proven benefit, with the long-term risk of scheduling sessions more frequently than is advisable. The criterion used in practice is not age, but the appearance of a persistent mark after the contraction is released. Once this threshold is crossed, spaced-out treatment makes sense; before this point, it does not.
In short — The preventive reasoning is mechanically sound, but its level of evidence rests on reported cases of monozygotic twins, not on controlled trials. In the office, the criterion for indication is not age but the appearance of a visible indentation at rest, after relaxation of the contraction.
What are the risks and complications of botulinum toxin?
Adverse effects are mostly mild and transient. The most characteristic is eyelid ptosis, which occurred after 0,7% of treatments in a series of nearly 8,000 injections. No serious adverse effects were reported in the landmark meta-analysis of 36 randomized trials.
It is helpful to distinguish three categories. Effects related to the injection procedure itself, which are the most frequent and commonplace. Effects related to the local diffusion of the product, which are what truly worry patients. And systemic effects, which are exceptional at the doses used in cosmetic medicine.
complication | Frequency | What there is to know |
|---|---|---|
Pain at the injection site | Very common, minimal | Brief, related to the sting itself. Applying cold reduces it. |
bruise | Frequent | Disappears in 3 to 7 days. Aggravated by aspirin and anti-inflammatories, which should be avoided the week before. |
Hematoma | Rare | Larger collection, particularly in the periorbital region. Resolves, but takes longer to disappear. |
cephalalgia | Frequent | Transient, occurring in the days following the session. In the reference randomized trial, it was reported by 11% of treated patients versus 20% in the placebo group. |
Edema, redness | Frequent, brief | A few hours. |
Drooping of the eyebrow tail | Infrequent | This results from overtreatment of the frontalis muscle, the only muscle that raises the eyebrow. It is almost always an error in dosage or level, not a random occurrence. It resolves within a few weeks. |
Eyelid ptosis | 0,7% of treatments | Partial drooping of the upper eyelid due to diffusion to the muscle that raises it. Temporary, resolving spontaneously within a few weeks. |
Asymmetry | Infrequent | A pre-existing asymmetry in facial expressions is present in most faces, often without the patient being aware of it; it becomes visible when muscle contraction is reduced. It should be identified and noted before the procedure. It can be corrected during the follow-up examination. |
Paresis of the smile | Rare, specific to the lower third | Related to diffusion to the lip elevator muscles during treatment of the commissure depressors or gummy smile. Transient. |
Dysphagia | Rare, specific to the neck | Difficulty swallowing after platysma treatment, due to diffusion to the deep neck muscles. Transient, but requires keeping doses below usual levels in patients with thin necks. |
Weak grip | Rare, specific to the palms | Following treatment of palmar hyperhidrosis. Transient, something to be aware of before treating a patient whose activity requires fine motor skills. |
Remote broadcast | Exceptional | Described in therapeutic indications at high doses, particularly in spastic children. Not reported at doses used in facial aesthetic medicine. |
Secondary resistance | Rare in aesthetic practice | Development of neutralizing antibodies reduces or negates the effect. This is favored by excessively short intervals and high doses per cycle. Prevention: maintain a 3- to 6-month interval between sessions. |
This prevents these complications
- A precise knowledge of functional anatomy: each injection point is determined by the targeted muscle and by the neighboring muscles that must not be reached.
- Modulated and not maximum doses, particularly on the frontalis muscle and on the low-dose areas of the lower third.
- Respecting the injection depth: superficial in the periorbital region, intramuscular on the masseters.
- The search for and documentation of a pre-existing asymmetry prior to the action.
- Respecting a period of 3 to 6 months between two sessions, which prevents secondary resistance.
- Informing the patient about what should prompt a consultation: marked asymmetry, difficulty swallowing, drooping eyelid.
Contraindications
- Myasthenia gravis and other neuromuscular junction disorders, in which nerve transmission is already impaired.
- Pregnancy and breastfeeding, as a precautionary measure, in the absence of sufficient safety data.
- Progressive skin infection at the injection site.
- Known hypersensitivity to one of the components.
- Certain ongoing treatments, particularly aminoglycoside antibiotics, can potentiate the effect. All treatments should be reported during your consultation.
In short — According to Dr. Stroumza-Escoffier, complications from botulinum toxin are mostly mild and transient: pain at the injection site, bruising, and headache. Diffusion complications — eyelid ptosis in 0,7% of treatments, eyebrow drooping, asymmetry, and dysphagia after neck treatment — are rarer and always reversible. No serious adverse effects were reported in the benchmark meta-analysis.
Who can inject botulinum toxin in France?
Botulinum toxin is a prescription-only medication. Its prescription for cosmetic purposes is restricted to five medical specialties: plastic, reconstructive, and aesthetic surgery; dermatology; facial and neck surgery; maxillofacial surgery; and ophthalmology. Any injection administered by another person constitutes the illegal practice of medicine.
This rule is not widely known and differs radically from that which applies to dermal fillers. Hyaluronic acid is a medical device: any properly trained physician can inject it. Botulinum toxin is a medication: its scope of prescription for cosmetic purposes is defined by the conditions of prescription and issuance of its marketing authorization, and it is restricted to the five specialties mentioned above. Therefore, the same practitioner may be authorized to prescribe one but not the other.
Three practical consequences follow from this. The product is reserved for professional use and can only be dispensed to doctors authorized to prescribe it; its sale to the public and its sale on the internet are prohibited; and advertising to the public for a specialty subject to prescription is also prohibited, which explains why no product name is mentioned on this page.
This framework is the subject of debate. The National Council of the Order of Physicians is advocating for its expansion to include specifically trained physicians, particularly those holding the inter-university diploma in aesthetic medicine created in 2024, whose first graduates completed their studies in June 2026. At the time of writing this article, in August 2026, no regulatory changes had been implemented: the five-specialty rule remained in effect. This page will be updated if the situation changes.
In short — In France, botulinum toxin is a prescription-only medication, but its prescription for cosmetic purposes is restricted to five specialties: reconstructive and cosmetic plastic surgery, dermatology, facial and neck surgery, maxillofacial surgery, and ophthalmology. This differs from the rule for hyaluronic acid, which can be injected by any trained physician.
Summary
The main danger in France is not the product itself, but the person administering it. Between August and September 2024, the National Agency for the Safety of Medicines reported eight serious cases of botulism following cosmetic injections performed by unqualified individuals. Further serious cases were reported in October 2025.
The patients in question presented with swallowing and speech difficulties, walking difficulties, blurred or double vision, and, in some cases, respiratory distress requiring hospitalization in intensive care, sometimes with a tracheotomy. These symptoms do not correspond to a common adverse effect of the treatment: they reflect the injection of inappropriate quantities, untraceable products obtained outside the legal supply chain, or adulterated preparations.
This phenomenon has a simple economic explanation. Demand is growing faster than the number of qualified practitioners, and this gap creates a parallel market where prices are low and availability is immediate. An abnormally low price is, in fact, the most reliable warning sign: a vial of botulinum toxin has a cost, and a service significantly below market price implies either a product of illegal origin or an injector who lacks the necessary qualifications to pay for.
HOW TO CHECK IF AN INJECTOR IS AUTHORIZED A doctor's qualifications are public. They can be consulted in the directory of the National Council of the Order of Physicians, using the practitioner's name. This directory lists their qualifying specialty—not any additional training they may have completed. For botulinum toxin for cosmetic purposes, only five qualifying specialties grant the right to prescribe it. Four signals should lead to a refusal: the absence of registration with the Order or a specialty that is not among the five; an injection carried out anywhere other than in a medical office, at home, in an institute or during a traveling "session"; the absence of prior consultation, examination and quote; and a price significantly lower than the market rate. The question of qualifications can be asked directly to the practitioner. It is legitimate, and a qualified physician will answer it without difficulty. |
In short — The ANSM (French National Agency for Medicines and Health Products Safety) reported eight serious cases of botulism between August and September 2024, followed by further cases in October 2025, after cosmetic injections performed by unqualified individuals — some patients requiring resuscitation. A doctor's qualifications can be verified in the Medical Council's directory, and a price significantly below market rate is the most reliable warning sign.
What happens during a session ?
It all begins with a medical consultation that includes a dynamic facial expression assessment. This consultation is free of charge. The injection itself lasts ten to fifteen minutes, without anesthesia and without any downtime.
The consultation verifies the indication and the absence of contraindications, analyzes facial expressions in motion, defines the areas and doses, and results in information and a quote. Reference photographs, both during contraction and at rest, are taken at this time: these serve as a basis for later comparison.
The injection uses a 34G needle—one of the finest available—and very small volumes, from 0,01 to 0,05 mL per point, distributed across several points on each muscle. The depth is adapted to the area: superficial in the periorbital region, intramuscular in thick muscles such as the frontalis or masseter. No anesthesia is necessary; applying cold improves comfort. The procedure is brief, and the patient leaves immediately.
The after-effects are mild: a visible injection site for a few hours, sometimes a bruise that fades in three to seven days, sometimes a transient headache. The first effects appear between the third and seventh day; the result is complete around the fifteenth day. It is at this point that it should be assessed.
The follow-up is tailored to the realities of practice: most patients send a photograph and a short video of their results, which are sufficient to confirm that no further touch-ups are necessary. If a wrinkle persists or an asymmetry appears, a follow-up appointment is scheduled two weeks later, and the touch-up is included.
Figure 7 — Key points for a botulinum toxin injection session: indications by facial area, technique—34G needle, superficial depth around the eye and intramuscular elsewhere, onset of effect in 3 to 7 days, optimal effect at two weeks, duration of action in 4 to 6 months—and consultation principles, including information and informed consent. Diagram created by Dr. Nathaniel Stroumza-Escoffier. The doses used in the practice are expressed in units of the specific botulinum toxin used and are not applicable to any other brand.
The instructions
- Avoid aspirin and non-prescribed anti-inflammatories the week before the session: they increase the risk of bruising.
- Do not massage or rub the treated areas for several hours afterward.
- Avoid intense exercise, saunas and steam rooms for twenty-four hours.
- It is common practice to recommend remaining upright for four hours after the injection. This precaution is standard, but its experimental basis is weak: it is suggested as a precaution, not because it has been proven effective.
- Do not schedule a first session within fifteen days before an important event: the result is only complete on the fifteenth day.
How much does a botulinum toxin injection cost in Paris?
The price is per vial, not per area. These procedures are not covered by health insurance. The initial consultation is free of charge; only the injection itself is billed, if it takes place.
Documents | Office fees |
|---|---|
Upper third of the face — one bottle | 400 € |
Complete treatment — upper third and lower third | 600 € |
Masseters — a bottle | 400 € |
Hyperhidrosis (armpits, palms or soles) — two bottles | 700 € |
Touch-up at the 15-day check-up, if necessary | included |
This pricing structure requires clarification because it is not widespread. Most practices charge per treated area. The price per bottle reflects the actual cost of the product used, thus preventing a per-area pricing system from becoming a marketing ploy. This is a deliberate choice, consistent with the principle that medicine is not practiced as a business.
Only the quote provided after the consultation is valid. Price should not be the deciding factor when choosing an injector; medical qualifications, anatomical knowledge, and the ability to manage side effects are. A price significantly lower than the market rate should prompt verification of the practitioner's qualifications and the product's origin.
Perspectives: towards toxins with different action profiles
All botulinum toxins authorized in aesthetic medicine today belong to serotype A. A different serotype, serotype E, is the subject of recent clinical work describing a new action profile: visible effect in a few hours and disappearance in about twenty days.
Serotype E also cleaves the SNAP-25 protein, but at a different site, which completely alters the kinetics: very rapid onset, short duration. A pivotal phase 3 study published in July 2026, conducted in 309 adults who had never received the toxin, reported an effect noticeable as early as eight hours, peaking on day seven, and returning to baseline levels around day twenty-one. The primary efficacy endpoint was met in 65,7% of treated participants compared to 1,2% in the placebo group. Reported adverse events were mostly mild and unrelated to the treatment, with no cases suggestive of distant spread.
The potential clinical benefit is twofold: allowing a hesitant patient to experience the effects of a toxin without a commitment of several months, and providing coverage for a one-off event. This is in no way a replacement for serotype A toxins, for which a four- to six-month duration remains the objective for the vast majority of requests. If such products were to become widespread, they would, however, alter the patient population structure: in practice, three out of ten patients have never received an injection, and this proportion would mechanically increase if the initial experience could be limited to three weeks.
A disclaimer is necessary. This data comes from a single trial, funded by the sponsoring laboratory, and this page does not comment on the availability of this type of product in France, nor on its inclusion in the practice's catalog. This section is strictly for informational purposes regarding the current state of research. Dr. Stroumza-Escoffier declares a consulting relationship with the laboratory in question: see the declaration of conflicts of interest below.
In short — Botulinum toxins used in aesthetics all belong to serotype A. A phase 3 study published in July 2026 describes a serotype E toxin with the opposite profile: noticeable effect as early as eight hours, maximum at seven days, disappearing around twenty-one days. This is a one-off trial, funded by its sponsor, and not an offer from the practice.
Who is Dr. Nathaniel Stroumza-Escoffier?
Dr. Nathaniel Stroumza-Escoffier is a qualified plastic surgeon specializing in plastic, reconstructive and aesthetic surgery (RPPS 10100674943), located at 11 rue du Faubourg Saint-Honoré in the 8th arrondissement of Paris.
- Qualification. Plastic, reconstructive and aesthetic surgery — RPPS 10100674943, registered with the French Medical Council. This is one of the five specialties authorized in France to prescribe botulinum toxin for aesthetic purposes.
- Hospital journey. Former assistant clinical head of the Hospitals of Paris — Tenon hospital (AP-HP).
- Areas of expertise. Minimally invasive techniques for the face and neck, regenerative aesthetic medicine, radiofrequency, minimally invasive breast surgery.
- Learned society. Member of the scientific committee of SOFCEP (French Society of Aesthetic Plastic Surgeons).
- Education. Over 100 physicians trained — 80 cosmetic doctors and 30 surgeons — in botulinum toxin, hyaluronic acid, biostimulator, skinbooster, and vitamin therapy injection techniques, in France and internationally. Presentations at specialist congresses (SOFCPRE, AMWC, IMCAS).
- Practice locations. Consultations and aesthetic medicine procedures at the office at 11 rue du Faubourg Saint-Honoré, Paris 8th. Surgical procedures at the Eiffel and Turin clinics.
DECLARATION OF CONFLICTS OF INTEREST Dr. Nathaniel Stroumza-Escoffier declares consulting relationships with InMode (radiofrequency devices), AbbVie/Allergan Aesthetics, and serves as a medical expert for Fillmed Laboratories. These relationships have no influence on the recommendations made during consultations, which are based on anatomical analysis and the patient's goals. No products are sold at the practice. |
Where to consult in Paris?
Facial aesthetic medicine consultations take place at the office at 11 rue du Faubourg Saint-Honoré, in the 8th arrondissement of Paris, in the immediate vicinity of the Madeleine and the Place de la Concorde.
The practice receives patients from Paris and the surrounding region, as well as patients from other parts of France and abroad. An initial consultation, free of charge, allows us to analyze facial expressions, verify the suitability of the procedure, define the treatment plan, and provide a cost estimate. Cosmetic procedures are performed at the practice; surgical interventions take place at a clinic.
Summary
I consider botulinum toxin to be the easiest procedure to perform and one of the most difficult to perform well. Injecting it is simple. Deciding where, how much, and especially where not to inject requires understanding a face in motion—and not just recognizing a wrinkle in a photograph.
The result I'm aiming for isn't a smooth forehead. It's a face whose expression remains intact, but whose tension has disappeared. The difference between the two almost always lies in the dosage and the preservation of the elevator muscles. A patient who can no longer raise their eyebrows hasn't been treated properly, regardless of the quality of their forehead at rest.
This is also why I chose to publish the doses I use. Not so they can be replicated—they can't be, since they depend on the product, the face, and the objective—but because a patient has the right to know what they are being injected with and in what quantity. Secrecy in this field has never protected anyone except bad injectors.
If you wish to reduce your expression lines without losing your expression, I would be happy to see you for a consultation at the office at 11 rue du Faubourg Saint-Honoré.
— Dr. Nathaniel Stroumza-Escoffier
Documents
Areas treated with Botox
- Forehead wrinkles
- Frown lines
- Crow's feet wrinkles
- Hyperhidrosis of the axillary region
- Gummy smile: lips
- Excessive sweating of the palms of the hands
- Excessive sweating of the soles of the feet
FAQ
What is a facial botulinum toxin injection?
This is a medical procedure involving the injection of very small amounts of botulinum toxin type A into specific facial muscles. The injected muscle temporarily relaxes, the overlying skin stops creasing during facial expressions, and expression lines are softened. The effect lasts 4 to 6 months.
Are botulinum toxin and "Botox" the same thing?
The term commonly known as Botox is a brand name that has become synonymous with the treatment in everyday language. The active ingredient is botulinum toxin type A. Several pharmaceutical products contain it, each with its own specific and non-interchangeable dosage units. Therefore, this page does not list any specific product names.
How exactly does botulinum toxin work?
It blocks the release of acetylcholine, the chemical messenger by which the nerve signals muscle contraction. It does this by cleaving a protein essential for this release, called SNAP-25. The muscle no longer receives the signal to contract. When the junction between the nerve and the muscle repairs itself, the contraction returns to normal.
Will the face appear frozen?
This is not the goal, nor is it the result of a well-dosed treatment. A frozen face results from an excessive dose or overly extensive treatment, particularly of the frontalis muscle. The approach taken in our practice is to modulate the contraction rather than eliminate it: the eyebrows should remain mobile.
What types of wrinkles can botulinum toxin treat?
Expression lines, those that appear during facial contractions: frown lines between the eyebrows, horizontal forehead wrinkles, crow's feet at the corners of the eyes. It also has targeted applications for wrinkles on the nose, gummy smile, lip flip, downturned corners of the mouth, chin prominence, vertical neck lines, and masseter muscles.
Which wrinkles cannot it treat?
Those that don't depend on muscle. Volume loss in the temples, cheeks, or under-eye circles can be addressed with fillers. Dull, dehydrated, or less dense skin is treated with skin boosters or collagen inducers. Established skin laxity in the neck or lower face cannot be corrected by injections.
How many units are needed to treat the forehead, glabella, or crow's feet?
In the office, treatment of the upper third of the face typically uses 20 units on the glabella, 20 units on the forehead, and 12 units per side on the crow's feet, for a total of 64 units. These values are indicative and specific to the pharmaceutical product used: the units measure a biological activity defined by each manufacturer and are not transferable from one product to another. The actual dose is determined during the consultation, based on muscle strength and the desired outcome.
And for the masseter muscles, the neck or the gummy smile?
The standard measurements used in the practice are 25 units per side for the masseter muscles, 20 units per side for the platysma muscle in the context of a Nefertiti lift, 10 units per side for a gummy smile, 4 units per side for a lip flip, and 2 units per side for commissure depressors. The same caveats apply: these units are specific to a given product, and these values are adjusted for each patient.
Why do the doses vary so much from one area to another?
Because they depend on the mass and function of the targeted muscle. The masseter is a powerful and large muscle, requiring fifty units; the depressors of the corner of the mouth are small and superficial, requiring only four. The lowest doses are also the most technically demanding: two units misplaced on the perioral region will alter the smile, whereas the same deviation would go unnoticed on a masseter.
How long does it take for the effect to appear?
The first effects appear between the third and seventh day. The result is complete around the fifteenth day. It is at this date that it must be judged, and not before.
How long does the effect last?
From 4 to 6 months depending on the area, the dose, and each individual's metabolism. The duration is generally shorter in highly mobile areas and in patients with high muscle mass. It tends to be slightly longer in patients treated regularly for several years.
Is it painful?
The discomfort is brief and mild. The needles used are very fine and the injected volumes very small. No anesthesia is necessary; applying cold improves comfort.
How long does a session last?
The injection itself takes ten to fifteen minutes, not including the prior consultation.
Is there social exclusion?
No. A puncture mark may remain visible for a few hours, and bruising is possible for three to seven days. However, it is advisable not to schedule your first session within fifteen days of an important event, as the full result is only achieved on the fifteenth day.
Is there a follow-up consultation?
It is not always necessary. Most patients send a photograph and a short video of their results, which is sufficient to confirm that no further touch-up is required. If a wrinkle persists or an asymmetry appears, a follow-up appointment is offered two weeks later, and the touch-up is included in the session fee.
Can the effect be reversed if the result is not satisfactory?
No. Unlike hyaluronic acid, which can be dissolved by an enzyme, there is no antidote to botulinum toxin. The effect disappears spontaneously within 4 to 6 months. This is precisely why the first session must be dosed carefully, with the possibility of further treatment at the two-week follow-up appointment.
What are the possible side effects?
The most frequent side effects are mild and transient: pain at the injection site, bruising, redness, swelling, and headache in the following days. Effects related to local diffusion of the product are less common: drooping of the outer eyebrow, asymmetry, and ptosis of the eyelids. In the landmark meta-analysis of 36 randomized trials, no serious adverse effects were reported.
What is eyelid ptosis and how often does it occur?
This is a partial drooping of the upper eyelid, due to the product spreading to the muscle that raises it. It is temporary and resolves spontaneously within a few weeks. In the largest published follow-up series, encompassing 7,938 treatments, it occurred after 0,7% of them, all resolving without any lasting effects.
Can neck treatment interfere with swallowing?
This is a rare but described complication following platysma treatment. It manifests as a transient difficulty swallowing, due to the product diffusing into the deep neck muscles. It necessitates keeping the dosage lower than usual for patients with thin necks and administering injections at multiple sites.
Are there any contraindications?
Yes. Myasthenia gravis and other neuromuscular junction disorders, pregnancy and breastfeeding, an active skin infection at the injection site, and known hypersensitivity to any of the components are contraindications. Certain treatments, particularly aminoglycoside antibiotics, may potentiate the effect and should be reported during a consultation.
Is it safe to inject during pregnancy or breastfeeding?
No. As a precautionary measure, cosmetic injections are postponed until after pregnancy and breastfeeding, due to a lack of sufficient safety data in this situation.
Should we be concerned about a long-term toxic effect?
The doses used in facial aesthetic medicine are incomparably lower than those of poisoning. The toxin is administered locally, never systemically, and its effect is localized to the muscle fibers near the injection site. The landmark meta-analysis reported no serious adverse effects, and follow-up of repeated treatments over three years shows no accumulation of risk.
Does the muscle atrophy if the injections are repeated?
A reduction in muscle volume is observed and desired in certain indications, particularly in the masseter muscles, where it is the expected effect. In the muscles of the upper third of the face, a decrease in contraction strength is observed in patients treated for a long time, which explains why the intervals between contractions may lengthen over time. This change is reversible upon discontinuation of treatment.
Can one become resistant to botulinum toxin?
It's possible, but rare in aesthetic practice. The body can develop neutralizing antibodies that reduce or cancel the effect. Identified contributing factors include excessively short intervals between sessions, high doses per cycle, and the amount of protein in the product used. Maintaining a three- to six-month interval between sessions is the primary preventative measure.
How often can the injections be repeated?
Between three and six months. This timeframe is not a commercial agreement: the close proximity of the sessions is one of the main factors in the development of neutralizing antibodies. In practice, maintenance two to three times a year corresponds to the duration of the effect.
At what age can one start?
There is no set age. The criterion used in practice is the appearance of a persistent indentation after the muscle contraction has relaxed; that is, the point at which the wrinkle begins to remain visible even with a relaxed face. Before this threshold, the benefit of treatment is not demonstrated.
Can botulinum toxin, hyaluronic acid and skinbooster be combined in the same session?
Yes, and it's common. The three don't act on the same level or through the same mechanism: the toxin relaxes the muscles responsible for expression lines, hyaluronic acid restores volume, and the skinbooster improves skin quality. Combining them doesn't increase the downtime or risks, and it saves the patient from having to make multiple appointments.
Does botulinum toxin have any medical indications?
Yes, and they predate its aesthetic use: blepharospasm, spasmodic torticollis, spasticity, overactive bladder, chronic migraine. Two indications are addressed in the office: hyperhidrosis — excessive sweating of the armpits, palms or soles — and bruxism, or jaw clenching, which simultaneously refines the lower third of the face.
Who can inject botulinum toxin in France?
For cosmetic purposes, only physicians specializing in five fields are authorized to administer it: plastic, reconstructive, and cosmetic surgery; dermatology; facial and neck surgery; maxillofacial surgery; and ophthalmology. For therapeutic purposes, any physician may prescribe it. Any cosmetic injection performed by another person constitutes the illegal practice of medicine and exposes the patient to serious adverse events, including cases of botulism reported by the ANSM (French National Agency for Medicines and Health Products Safety).
How to recognize an illegal injector
Four signals should lead to refusal: a specialty that is not among the five authorized, verifiable on the directory of the National Council of the Order of Physicians; an injection carried out elsewhere than in a medical office; the absence of prior consultation, examination and quote; and a price significantly lower than the market, which indicates either a product of illegal origin, or an unqualified injector.
Why are no product names mentioned on this page?
Because botulinum toxin is a prescription-only medication, and advertising this type of medication to the public is prohibited in France, the name of the product used, along with its characteristics, will be provided to you during your consultation.
What is the price of a botulinum toxin injection in Paris?
At Dr. Stroumza-Escoffier's practice, the price is calculated per bottle: €400 for the upper third of the face, €600 for a complete treatment encompassing both the upper and lower thirds, €400 for the masseter muscles, and €700 for the treatment of hyperhidrosis. The initial consultation is free of charge, and any touch-up at the two-week follow-up appointment is included. These procedures are not covered by insurance.
Is it covered by Social Security?
Not for cosmetic purposes. However, certain therapeutic indications for botulinum toxin are covered, within a separate framework and with a specific medical prescription.
How to make an appointment in Paris?
Consultations take place at 11 rue du Faubourg Saint-Honoré, Paris 8th arrondissement. Appointments can be made via the website's contact page.
WARNING This article is for informational purposes only and does not replace a medical consultation. The indications, dosages, and areas treated are subject to an individualized medical evaluation. The dosages mentioned are indicative, specific to a particular pharmaceutical product, and do not constitute a prescription or a reproducible protocol. As with any cosmetic procedure, the result cannot be guaranteed: it depends on facial expressions, muscle strength, and factors specific to each individual. The figures cited come from published studies and do not guarantee an individual result. No pharmaceutical product is named: advertising prescription drugs to the public is prohibited. |
References
Indexed scientific references, verified on PubMed:
- Carruthers JD, Carruthers JA. Treatment of glabellar frown lines with C. botulinum-A exotoxin. J Dermatol Surg Oncol. 1992;18(1):17-21. PMID 1740562. DOI 10.1111/j.1524-4725.1992.tb03295.x
- Blasi J, Chapman ER, Link E, Binz T, Yamasaki S, De Camilli P, Südhof TC, Niemann H, Jahn R. Botulinum neurotoxin A selectively cleaves the synaptic protein SNAP-25. Nature. 1993;365(6442):160-3. PMID 8103915. DOI 10.1038/365160a0
- Carruthers JD, Lowe NJ, Menter MA, Gibson J, Eadie N. Double-blind, placebo-controlled study of the safety and efficacy of botulinum toxin type A for patients with glabellar lines. Plast Reconstruction Surg. 2003;112(4):1089-98. PMID 12973229. DOI 10.1097/01.PRS.0000076504.79727.62
- Naumann M, Jankovic J. Safety of botulinum toxin type A: a systematic review and meta-analysis. Curr Med Res Opin. 2004;20(7):981-90. PMID 15265242. DOI 10.1185/030079904125003962
- Schlessinger J, Dover JS, Joseph J, Monheit G, Nelson DB, Albright CD, Axford-Gatley RA, Cohen JL. Long-term safety of abobotulinumtoxinA for the treatment of glabellar lines: results from a 36-month, multicenter, open-label extension study. Dermatol Surg. 2014;40(2):176-83. PMID 24372978. DOI 10.1111/dsu.12404
- Bellows S, Jankovic J. Immunogenicity associated with botulinum toxin treatment. Toxins (Basel). 2019;11(9):491. PMID 31454941. DOI 10.3390/toxins11090491
- Binder WJ. Long-term effects of botulinum toxin type A on facial lines: a comparison in identical twins. Arch Facial Plast Surg. 2006;8(6):426-31. PMID 17116793. DOI 10.1001/archfaci.8.6.426
- Rivkin A, Binder WJ. Long-term effects of onabotulinumtoxinA on facial lines: a 19-year experience of identical twins. Dermatol Surg. 2015;41 Suppl 1:S64-6. PMID 25548847. DOI 10.1097/DSS.0000000000000193
- Lain E, George R, Kavali C, Keaney T, LaTowsky B, Rivers JK, Marcus K, Weiss R, Yoelin S, et al. Rapid results with trenibotulinumtoxinE for the treatment of glabellar lines in toxin-naïve adults: safety, efficacy, and satisfaction findings from a pivotal phase 3 study. Aesthet Surg J. 2026. PMID 42495855. DOI 10.1093/asj/sjag154
Regulatory and institutional sources: National Agency for the Safety of Medicines and Health Products (ANSM) — warnings on illegal botulinum toxin injection practices · Health insurance (ameli.fr) — file “Botulinum toxin injection” · National Council of the Order of Physicians · Articles L.5122-6, R.4127-13 and R.4127-19 of the Public Health Code.
This article is for informational purposes only and does not replace a medical consultation.