Botulinum toxin: complete guide to aesthetic and medical indications
Botulinum toxin is one of the most versatile drugs in modern medicine. Its ability to block the release of acetylcholine—the neurotransmitter that activates muscles and glands—allows it to treat conditions as diverse as facial wrinkles, chronic migraine, muscle spasticity and hyperhidrosis. Only onabotulinumtoxinA (Botox) has FDA approval for 11 therapeutic and 3 aesthetic indications, and the other formulations add their own indications. If you want to understand what botulinum toxin is, its origin and molecular mechanism, consult our guide to Botox. This article focuses on what botulinum toxin treats: the complete list of indications with their evidence.
Summary
- Botulinum toxin type A has more than 20 FDA-approved indications (aesthetic, neurological, urological, ophthalmological) and dozens of off-label uses with clinical support.
- In aesthetics, the three approved zones are glabellar lines, crow's feet and forehead; but there are at least 10 additional facial applications with published evidence (gummy smile, lip flip, chin, platysmal bands, among others).
- In medicine, approved indications include chronic migraine, spasticity, cervical dystonia, overactive bladder, axillary hyperhidrosis, sialorrhea, blepharospasm and strabismus.
- Botox and Dysport units are not interchangeable: the accepted clinical conversion ratio is approximately 1 : 2.5–3 (Botox : Dysport).
- There are promising emerging indications such as major depression, neuropathic pain and scar prevention, still in research phase.
What is botulinum toxin used for?
Botulinum toxin is used for any condition where it would be beneficial to temporarily reduce the activity of a muscle or gland. Its first FDA approval was in 1989 for strabismus and blepharospasm. Since then, its indications have continued to grow: in 2002 approval came for glabellar lines, in 2010 for chronic migraine, in 2013 for overactive bladder, and approvals for pediatric spasticity came in 2019-2020.
Indications are classified into three categories:
- Approved (on-label): the specific brand has demonstrated efficacy and safety in phase III clinical trials and has regulatory approval (FDA, EMA, COFEPRIS, ANVISA or other agencies).
- Off-label with clinical support: use not included in the technical sheet, but supported by published evidence and extended clinical practice.
- Under investigation: preliminary promising evidence, usually in phase II trials or case series.
To understand the differences between available brands—Botox, Dysport, Xeomin, Jeuveau, Myobloc—consult our comparison of botulinum toxin brands.
Approved aesthetic indications: the three classic zones
The three facial zones with FDA approval for aesthetic use of botulinum toxin type A are glabellar lines (between the eyebrows), forehead lines and crow's feet. Botox Cosmetic (onabotulinumtoxinA) is the only brand approved by the FDA for all three zones; Dysport and Xeomin have FDA approval only for glabellar lines.
Glabellar lines (between the eyebrows or "eleven lines")
Glabellar lines are the vertical wrinkles between the eyebrows caused by repeated contraction of the corrugator and procerus muscles. It is the aesthetic indication with the longest approval time (since 2002 for Botox Cosmetic).
- Approved dose: Botox 20 U in 5 points · Dysport 50 U in 5 points · Xeomin 20 U in 5 points
- Duration: 3–4 months typically
- Approved brands (FDA): Botox Cosmetic, Dysport, Xeomin, Jeuveau
Forehead horizontal lines
Horizontal lines on the forehead result from contraction of the frontalis muscle. They are frequently treated together with the glabella.
- Approved dose (Botox Cosmetic): 20 U in 5 points
- Typical dose (Dysport, off-label for this zone): 20–40 U in 4–8 points
- Duration: 3–4 months
- Approved brand (FDA) for this zone: Botox Cosmetic only (the others treat this zone off-label)
Crow's feet (lateral canthal lines)
Crow's feet are the radial lines in the lateral region of the eye, produced by contraction of the orbicularis oculi muscle.
- Approved dose (Botox Cosmetic): 24 U total (12 U per side, 3 points per side)
- Typical dose (Dysport, off-label for this zone): 30–60 U total (15–30 U per side)
- Duration: 3–4 months
- Approved brand (FDA) for this zone: Botox Cosmetic only
Aesthetic indications off-label with clinical support
Beyond the three classic zones, botulinum toxin is widely used in at least 10 additional facial and cervical areas. These uses are off-label but are supported by international consensus, case series and published clinical trials. The following doses are expressed in units of onabotulinumtoxinA (Botox); for Dysport, multiply by a factor of approximately 2.5–3.
Bunny lines (nasal wrinkles)
Bunny lines are the diagonal wrinkles on either side of the nasal bridge that appear when scrunching the nose. The transverse nasalis muscle is injected.
- Dose: 4–10 U total (2–5 U per side)
- Points: 1–2 per side, superficial
- Duration: 3–4 months
Eyebrow lift (chemical browlift)
Botulinum toxin can lift the tail of the eyebrow by selectively relaxing the lateral portion of the orbicularis oculi, releasing the downward pull.
- Dose: 2–5 U per point in lateral orbicularis
- Points: 2–3 per side
- Duration: 3–4 months
Gummy smile (gingival smile)
Gingival smile—excessive gum display when smiling—is frequently produced by hyperactivity of the levator labii superioris and alae nasi (LLSAN) muscle. Botulinum toxin relaxes these muscles to limit the elevation of the lip.
- Dose: 2–4 U per side (general rule: 1 U for each mm of exposed gum)
- Points: 1 point per side 1 cm lateral to the nasal ala; in mixed gingival smile 1–2 points are added in zygomaticus muscles
- Duration: 3–4 months
Lip flip
The lip flip slightly everts the upper lip border by relaxing the orbicularis oris, creating the appearance of fuller lips without the need for filler.
- Dose: 2–6 U total (1–3 U per side of Cupid's bow)
- Points: 2–4, 1 mm above the vermillion border
- Duration: 6–8 weeks (less than other zones due to high orbicularis mobility)
Perioral lines (barcode lines)
Vertical wrinkles around the lips are softened with microdoses in the orbicularis oris.
- Dose: 4–8 U total (1–2 U per point)
- Points: 4–6 symmetric points over the vermillion border
- Duration: 2–3 months
Chin "orange peel" (mentalis)
Involuntary contraction of the mentalis muscle produces a rough or "orange peel" appearance on the chin. Botulinum toxin relaxes the mentalis to smooth the texture.
- Dose: 4–8 U total
- Points: 2 deep points adjacent to the midline, or 1 central point
- Duration: 3–4 months
Downturned mouth corners (DAO)
Contraction of the depressor anguli oris (DAO) pulls the mouth corners downward, giving a sad or angry appearance. Botulinum toxin relaxes this muscle to subtly lift the corners.
- Dose: 4–8 U total (2–4 U per side)
- Points: 1–2 per side, at the mandibular border
- Duration: 3–4 months
Masseters (jawline slimming and bruxism)
Injection into the masseter muscles reduces their volume through gradual atrophy, slimming the lower third of the face. It is also the most established off-label treatment for bruxism and temporomandibular disorder (TMD).
- Dose: 25–50 U per side (50–100 U total)
- Points: 3–5 per side in the body of the masseter
- Duration: 4–6 months; mandibular slimming becomes visible at 4–8 weeks
Platysmal bands
The vertical bands of the neck are visible extensions of the platysma muscle. Botulinum toxin is injected directly into the bands to smooth them.
- Dose: 10–30 U total (2–5 U per point, up to 5 points per band)
- Points: every 2 cm along the band, from the mandible downward
- Duration: 3–4 months
Nefertiti lift
The Nefertiti lift uses injections along the mandibular border in the platysma to improve the definition of the chin and jaw contour, countering the downward pull of the platysma on the lower third of the face.
- Dose: 10–20 U total (2–4 U per point)
- Points: 4–6 along the mandibular border
- Duration: 3–4 months
Approved medical indications
Botulinum toxin has regulatory approvals for multiple medical conditions. The following are indications with FDA approval with at least one brand.
Chronic migraine
Botulinum toxin (only onabotulinumtoxinA/Botox) has FDA approval since 2010 for prophylaxis of headaches in adults with chronic migraine, defined as ≥15 days of headache per month with episodes of ≥4 hours. It is not approved for episodic migraine (<15 days/month).
- Protocol: PREEMPT — 155 U distributed in 31 injection points in 7 muscle groups of the head and neck (frontal, glabella, temporal, occipital, cervical paravertebral and trapezius). Up to 40 additional U can be added in 8 points following the pain ("follow the pain"), for a maximum of 195 U.
- Frequency: every 12 weeks
- Approved brand: Botox (onabotulinumtoxinA)
Spasticity (upper and lower limb)
Botulinum toxin is approved for spasticity in adults and pediatric patients ≥2 years. It is used in conditions such as cerebral palsy, stroke, multiple sclerosis and spinal cord injury.
- Dose (Botox): up to 400 U distributed among affected muscles; maximum cumulative dose of 360 U in 3 months
- Dose (Dysport): up to 1,500 U combined between upper and lower limbs
- Approved brands: Botox, Dysport, Xeomin
Cervical dystonia (spasmodic torticollis)
Cervical dystonia causes involuntary contractions of the neck muscles, producing abnormal head postures and pain. Botulinum toxin has been the first-line treatment since 2000.
- Dose (Botox): variable according to postural pattern, typically 100–300 U distributed among affected muscles
- Dose (Dysport): 500–1,000 U; recommended initial dose of 500 U
- Approved brands: Botox, Dysport, Xeomin, Myobloc (rimabotulinumtoxinB)
Overactive bladder
Botulinum toxin is injected into the detrusor muscle of the bladder to treat overactive bladder (OAB) with symptoms of urgency, frequency and urge urinary incontinence, when anticholinergics are not sufficient. It is also approved for urinary incontinence from detrusor hyperactivity associated with neurological condition (spinal cord injury, multiple sclerosis).
- Dose: 100 U in 20 detrusor points (idiopathic OAB) · 200 U in 30 points (neurogenic detrusor)
- Duration: 6–9 months
- Approved brand: Botox (onabotulinumtoxinA)
Severe primary axillary hyperhidrosis
Botulinum toxin blocks the release of acetylcholine in eccrine sweat glands, reducing sweat production. It is approved for severe axillary hyperhidrosis that does not respond adequately to topical treatments.
- Dose: 50 U per axilla (100 U total), distributed in 10–15 points per axilla
- Duration: 6–9 months (longer than in muscular indications)
- Approved brand (FDA): Botox (onabotulinumtoxinA)
Use in palmar, plantar and craniofacial hyperhidrosis is off-label but widely practiced.
Chronic sialorrhea (sialorrhea/excessive drooling)
Chronic sialorrhea—excessive saliva production—is frequent in neurological diseases such as Parkinson's and ALS. Botulinum toxin is injected into the salivary glands (parotid and submandibular) to reduce secretion.
- Dose (Xeomin): 100 U distributed in 4 points (salivary glands)
- Duration: 3–4 months
- Approved brands: Xeomin (incobotulinumtoxinA) for patients ≥2 years, Myobloc (rimabotulinumtoxinB) for adults
Blepharospasm
Blepharospasm is a focal dystonia that causes involuntary eyelid contractions, potentially leading to functional blindness. It was one of the first approved indications (1989).
- Dose (Botox): 1.25–2.5 U per point, 3 points per affected eye; maximum recommended dose of 30 U per eye
- Approved brands: Botox, Xeomin
Strabismus
Strabismus—misalignment of visual axes—was the first approved indication for botulinum toxin (1989). It is injected into the hyperactive extraocular muscle.
- Dose (Botox): 1.25–5 U per muscle according to the degree of deviation
- Approved brand: Botox (onabotulinumtoxinA) for patients ≥12 years
Indications under investigation
These indications have preliminary promising evidence but do not yet have regulatory approval. Their use is experimental or compassionate.
Major depression
Several randomized clinical trials have demonstrated that injection of botulinum toxin into the glabellar region—associated with frowning expression—can significantly reduce depressive symptoms. A 2024 meta-analysis including 21 studies with 471 patients reported significant reductions in symptoms of major depression, borderline personality disorder and social anxiety. The proposed mechanism includes disruption of negative facial feedback (facial feedback hypothesis) and reduction of amygdala hyperactivity. The therapeutic efficacy appears comparable to that of SSRIs, with faster onset of action.
- Dose in studies: 29–100 U in glabella (protocol similar to aesthetic)
- Status: phase II/III; not approved
Neuropathic pain
Botulinum toxin has shown analgesic effects in multiple conditions of neuropathic pain—trigeminal neuralgia, diabetic neuropathy, postherpetic neuralgia—through inhibition of CGRP release, substance P and reduction of TRPV1 receptor expression. In trigeminal neuralgia, randomized controlled studies report response rates of 70–100% with significant pain reduction.
- Dose in studies: 20–100 U subcutaneous or intradermal in the painful area ("follow the pain")
- Status: growing evidence; not formally approved for neuropathic pain
Scar prevention and treatment
Recent meta-analyses of randomized controlled trials with more than 600 patients demonstrate that perilesional injection of botulinum toxin type A in the early phase of scar formation significantly reduces scores on the Vancouver Scar Scale (VSS), scar width and pain/itch scores. The mechanism includes reduction of muscle tension on the wound and inhibition of inflammatory mediators (glutamate, substance P).
- Dose in studies: variable; early perilesional injection (first days post-closure)
- Status: promising evidence; not approved as a formal indication
Other indications under exploration
Active research includes paroxysmal atrial fibrillation (epicardial injection during cardiac surgery), essential tremor of the upper limb (phase II completed with positive results for Botox in 2025), sleep bruxism, esophageal achalasia, gastroparesis and plantar fasciitis, among others.
Master table of indications
Doses are expressed in units of onabotulinumtoxinA (Botox) except where Dysport is specified. The clinically accepted conversion ratio is Botox : Dysport ≈ 1 : 2.5–3. The brands listed are those with FDA approval for that specific indication; the absence of a brand does not mean it does not work, only that it does not have that particular approval.
Aesthetic indications
| Indication | Status | Approved brand(s) | Typical dose (Botox) | Duration |
|---|---|---|---|---|
| Glabellar lines | FDA | Botox, Dysport, Xeomin, Jeuveau | 20 U (5 points) | 3–4 months |
| Forehead lines | FDA (Botox) | Botox Cosmetic | 20 U (5 points) | 3–4 months |
| Crow's feet | FDA (Botox) | Botox Cosmetic | 24 U (6 points) | 3–4 months |
| Bunny lines | Off-label | — | 4–10 U | 3–4 months |
| Eyebrow lift | Off-label | — | 4–10 U | 3–4 months |
| Gummy smile | Off-label | — | 4–8 U | 3–4 months |
| Lip flip | Off-label | — | 2–6 U | 6–8 weeks |
| Perioral lines | Off-label | — | 4–8 U | 2–3 months |
| Chin (orange peel) | Off-label | — | 4–8 U | 3–4 months |
| Downturned mouth corners (DAO) | Off-label | — | 4–8 U | 3–4 months |
| Masseters (slimming/bruxism) | Off-label | — | 50–100 U total | 4–6 months |
| Platysmal bands | Off-label | — | 10–30 U | 3–4 months |
| Nefertiti lift | Off-label | — | 10–20 U | 3–4 months |
Medical indications
| Indication | Status | Approved brand(s) | Typical dose (Botox) | Duration |
|---|---|---|---|---|
| Chronic migraine | FDA | Botox | 155–195 U (31–39 points) | 12 weeks |
| Spasticity (adult) | FDA | Botox, Dysport, Xeomin | Up to 400 U (Botox) | 3–4 months |
| Cervical dystonia | FDA | Botox, Dysport, Xeomin, Myobloc | 100–300 U (Botox) | 3–4 months |
| Overactive bladder | FDA | Botox | 100 U (20 points) | 6–9 months |
| Neurogenic detrusor | FDA | Botox | 200 U (30 points) | 6–9 months |
| Axillary hyperhidrosis | FDA | Botox | 50 U per axilla | 6–9 months |
| Chronic sialorrhea | FDA | Xeomin, Myobloc | 100 U Xeomin (4 points) | 3–4 months |
| Blepharospasm | FDA | Botox, Xeomin | 1.25–2.5 U × 3 points/eye | 3–4 months |
| Strabismus | FDA | Botox | 1.25–5 U per muscle | 3–4 months |
Indications under investigation
| Indication | Status | Evidence | Dose in studies |
|---|---|---|---|
| Major depression | Investigation | Multiple RCTs; 2024 meta-analysis | 29–100 U in glabella |
| Neuropathic pain | Investigation | RCT in trigeminal neuralgia | 20–100 U subcutaneous |
| Hypertrophic scars | Investigation | Meta-analysis of 12 RCTs (644 patients) | Variable, perilesional |
| Essential tremor | Investigation | Phase II positive (2025) | Under evaluation |
| Atrial fibrillation | Investigation | Case series | Epicardial injection |
Conversion between brands: a critical note
The units of Botox (onabotulinumtoxinA) and Dysport (abobotulinumtoxinA) are not interchangeable. The most clinically accepted conversion ratio is 1 : 2.5–3 (Botox : Dysport), although it varies according to indication and patient. A higher ratio (1:4 or 1:5) is considered overdosing Dysport and is associated with more adverse effects. Xeomin (incobotulinumtoxinA) uses a conversion ratio of approximately 1:1 compared to Botox. For more detail, consult our guide to botulinum toxin brands.
How long does the effect last according to indication?
The duration of the effect varies significantly depending on the target tissue. In small facial muscles (aesthetic facial), the effect typically lasts 3–4 months. In larger muscles such as the masseter, it can extend to 4–6 months. Indications on glands and smooth muscle—hyperhidrosis, overactive bladder—show longer durations, of 6–9 months, because glandular reinnervation is slower than muscular. With repeated treatments at regular intervals, some patients report that the duration gradually extends.
Frequently asked questions
What is botulinum toxin used for besides wrinkles?
Botulinum toxin has more than 20 FDA-approved indications beyond wrinkles. Medical indications include chronic migraine, spasticity in adults and children, cervical dystonia, overactive bladder, severe axillary hyperhidrosis, chronic sialorrhea, blepharospasm and strabismus. It is also used off-label for bruxism, neuropathic pain and mandibular slimming, among others. Its acetylcholine-blocking mechanism is useful in any condition where reduction of muscle or gland activity is needed.
How many Botox units are needed for the forehead?
The FDA-approved dose for horizontal forehead lines is 20 units of Botox Cosmetic distributed in 5 injection points. In clinical practice, doses may vary between 10 and 30 units according to muscle strength, forehead size and the patient's aesthetic goals. In men, higher doses are frequently required. It is important that the forehead be treated together with the glabella to avoid compensatory eyebrow elevation.
Is Botox for migraine the same as aesthetic Botox?
It is exactly the same molecule—onabotulinumtoxinA—but the protocol is very different. Chronic migraine treatment uses 155–195 units distributed in 31–39 injection points in 7 muscle groups of the head and neck (PREEMPT protocol), while typical full facial aesthetic use uses 40–64 units in 3 zones. Chronic migraine is defined as ≥15 days of headache per month; botulinum toxin is not approved for episodic migraine. Only Botox (not Dysport or Xeomin) has this approval.
What is the Nefertiti lift with botulinum toxin?
The Nefertiti lift is an off-label technique that uses botulinum toxin injections along the mandibular border in the platysma muscle to improve the definition of the mandible and chin contour. Typically 10–20 units of Botox are injected in 4–6 points. By relaxing the downward pull of the platysma on the lower third of the face, a subtle "lifting" effect is achieved without surgery. It is common to combine it with the treatment of platysmal bands of the neck.
Can botulinum toxin be used for excessive sweating?
Yes. Botulinum toxin is FDA-approved for severe primary axillary hyperhidrosis that does not respond to topical treatments, with a dose of 50 units of Botox per axilla. The effect lasts 6–9 months, significantly longer than in muscular indications. Use in palmar, plantar and craniofacial hyperhidrosis is off-label but widely practiced with good evidence. The mechanism is the blockade of acetylcholine release in eccrine sweat glands.
Can botulinum toxin help with depression?
The evidence is promising but not yet conclusive. Multiple randomized clinical trials and a 2024 meta-analysis with 471 patients have demonstrated that injection of botulinum toxin into the glabellar region can significantly reduce depressive symptoms. The proposed mechanism is twofold: disruption of negative facial feedback (by preventing frowning) and direct effects on brain circuits, including reduction of amygdala hyperactivity. However, it does not have regulatory approval for this indication and larger studies are needed.
What is the difference between Botox and Dysport in dosage?
Botox and Dysport units are not equivalent. The most clinically accepted conversion ratio is 1 unit of Botox for every 2.5–3 units of Dysport. Thus, 20 units of Botox in the glabella equals 50 units of Dysport. Higher ratios (1:4 or 1:5) are considered overdosing Dysport. For Xeomin, the conversion is approximately 1:1 compared to Botox. An experienced physician adjusts the dose individually considering muscle mass, previous response and the patient's goals.
How long does botulinum toxin take to work?
The onset of action depends on the indication. In facial aesthetic indications, the first effects are noticed between 24 and 72 hours, with maximum effect at 10–14 days. In bruxism, pain relief appears in 1–2 weeks, but mandibular slimming requires 4–8 weeks of gradual muscle atrophy. In chronic migraine, full benefits may require 2–3 treatment cycles (6–9 months). In hyperhidrosis and overactive bladder, the response is usually evident in the first week.
Is it safe to inject botulinum toxin outside the face?
Yes, as long as it is performed by a trained physician with anatomical knowledge of the area. Botulinum toxin is routinely injected in the neck (cervical dystonia, platysmal bands), armpits (hyperhidrosis), limbs (spasticity), bladder (via cystoscopy), and salivary glands (sialorrhea). Each area has its own safety profile and specific dose. The fundamental principle is that safety depends on the correct dose in the correct place, not on the body region.
Can botulinum toxin help with scars?
Recent evidence is promising. Meta-analyses of randomized controlled trials with more than 600 patients demonstrate that early perilesional injection of botulinum toxin type A significantly reduces scores on scarring scales, decreases scar width and improves pain and itching symptoms, without significant adverse effects. The mechanism includes reduction of muscle tension on the wound and inhibition of inflammatory mediators. However, it still lacks regulatory approval and larger studies are needed.
How often are touch-ups needed?
The frequency of treatment varies according to indication. In facial aesthetics, typical intervals are 3–4 months. In chronic migraine, the protocol establishes every 12 weeks. In hyperhidrosis and overactive bladder, intervals are longer: 6–9 months. In masseters for bruxism, initially every 4–6 months is recommended, but with successive treatments the muscle can "retrain" and intervals can be spaced out. It is not recommended to inject more frequently than indicated for each zone, as this increases the risk of developing neutralizing antibodies.
What happens if I stop getting botulinum toxin?
The effect of botulinum toxin is completely reversible. When reinnervation is complete—typically between 3 and 6 months after injection—the muscle or gland recovers its normal pre-treatment function. There is no rebound effect: wrinkles do not worsen, sweating does not increase, and migraine does not intensify compared to the pre-treatment state. In the case of masseters treated for bruxism, the muscle atrophy achieved may be partially maintained if clenching habits have been modified.