Botox is best known for smoothing wrinkles, but one of its longest-standing FDA-approved uses has nothing to do with cosmetics. In 2004, the FDA approved onabotulinumtoxinA (Botox) for the treatment of severe primary axillary hyperhidrosis — excessive underarm sweating that is not adequately managed by topical antiperspirants. It remains one of the most effective non-surgical treatments for this condition, with clinical studies documenting sweat reduction of 82–87% and patient satisfaction rates up to 98%.
This article covers how Botox works for hyperhidrosis, what the FDA approved it for (and what remains off-label), what the evidence says about efficacy and safety, how long results last, what it costs, and how it compares to alternative treatments.
What hyperhidrosis is and why it matters
Hyperhidrosis is a disorder in which the sweat glands become overactive, producing perspiration well beyond what the body needs for thermoregulation. The International Hyperhidrosis Society estimates that approximately 4.8% of the US population — roughly 15.3 million people — live with hyperhidrosis, though many never seek treatment.
There are two forms:
- Primary hyperhidrosis has no identifiable underlying medical cause. It typically begins in childhood or adolescence and most commonly affects the underarms (axillary), palms (palmar), soles of the feet (plantar), or face and head (craniofacial). It is believed to result from overactive signaling in the sympathetic nervous system.
- Secondary hyperhidrosis is caused by an underlying condition — menopause, thyroid disorders, diabetes, certain medications, neurological conditions, or some cancers. Treatment should address the underlying cause.
Primary hyperhidrosis significantly impacts quality of life. Patients report avoiding social situations, career limitations, clothing restrictions, and emotional distress. A 2026 phase 3 study published in Aesthetic Surgery Journal (Li et al.) confirmed that botulinum toxin treatment produces clinically meaningful improvement in quality-of-life measures.
How Botox stops excessive sweating
Botox works for hyperhidrosis through the same mechanism that makes it effective for wrinkles — but targeting a different receptor. In wrinkle treatment, Botox blocks acetylcholine release at the neuromuscular junction, relaxing facial muscles. In hyperhidrosis treatment, it blocks acetylcholine release at the junction between nerve endings and eccrine sweat glands.
Eccrine sweat glands are innervated by sympathetic nerve fibers that use acetylcholine as their neurotransmitter. When Botox is injected into the skin of the affected area, it prevents the nerve terminals from releasing acetylcholine. Without this chemical signal, the sweat glands in the treated area stop producing sweat.
This is a localized effect. Botox does not enter the bloodstream or affect sweating in untreated areas. The body gradually forms new nerve terminals over months, which is why the effect is temporary.
FDA-approved vs off-label use
FDA-approved: underarm (axillary) hyperhidrosis. Botox received FDA approval in 2004 specifically for severe primary axillary hyperhidrosis that is inadequately managed with topical agents. This is the only hyperhidrosis indication on the Botox label in the United States.
The approval was supported by two pivotal randomized, double-blind, placebo-controlled trials. In these studies, patients receiving Botox showed a statistically significant reduction in sweat production measured by gravimetric assessment, with the median duration of effect ranging from 175 to 238 days (approximately 6–8 months) per treatment session.
Off-label but widely used: other body areas. Dermatologists and other qualified practitioners commonly use Botox off-label for hyperhidrosis of the palms, soles of the feet, face, and scalp. The mechanism is identical, and clinical evidence supports efficacy in these areas, but insurance coverage is less consistent because the FDA has not specifically approved these indications.
The International Hyperhidrosis Society notes that at least 20 countries have approved Botox for underarm excessive sweating, and multiple botulinum toxin formulations are used worldwide for this purpose.
What the evidence shows
The clinical evidence for Botox in hyperhidrosis is robust:
Sweat reduction. Studies consistently show 82–87% reduction in sweat production in treated areas. UCLA Health reports that the International Hyperhidrosis Society has found Botox injections decrease excessive sweating by more than 85%.
Duration. A systematic review of the pivotal trials found median treatment effect duration of 175–238 days per injection session, with the possibility for retreatment 8 weeks after each injection. In clinical practice, most patients report 4–6 months of significant relief, with some experiencing benefits up to 12 months.
Patient satisfaction. Baylor College of Medicine reports satisfaction rates up to 98% in clinical studies. The 2026 phase 3 study by Li et al. in Aesthetic Surgery Journal further confirmed efficacy and safety in Chinese patients with primary axillary hyperhidrosis.
Safety. A comprehensive treatment review published in PMC (PMCID: PMC10374185) analyzed the development and clinical impact of onabotulinumtoxinA for hyperhidrosis. The review concluded that Botox is effective and well-tolerated, with adverse events generally mild and localized: pain, swelling, and bruising at injection sites. There has been no evidence of patients developing tolerance over time, meaning the number of units required typically remains consistent with repeated treatments.
Comparative studies. Available evidence suggests that different botulinum toxin type A formulations (Botox, Dysport, Xeomin) have comparable efficacy for hyperhidrosis. Aetna's clinical policy bulletin notes that botulinum toxin A and botulinum toxin B are comparably effective.
How the procedure works
The treatment protocol for underarm hyperhidrosis is straightforward:
Diagnosis confirmation. The provider confirms primary hyperhidrosis, typically using the Hyperhidrosis Disease Severity Scale (HDSS). A score of 3 or 4 (intolerable or barely tolerable sweating that always or frequently interferes with daily activities) is the treatment threshold.
Starch-iodine test (optional). An iodine solution is applied to the underarm, followed by starch powder. Areas of excessive sweating turn dark blue-black, mapping the treatment zone.
Injections. Approximately 15–20 injections are distributed evenly across each underarm using a very fine needle. A standard treatment uses 50 units of Botox per underarm (100 units total). Each injection delivers a small amount of Botox just below the skin surface.
Session time. 15–30 minutes total.
Anesthesia. Topical numbing cream, ice, or vibration anesthesia may be used. Some patients opt for no anesthesia, as the injections use very fine needles.
Recovery. No downtime. Patients can return to normal activities immediately. Exercise should be avoided for 24 hours.
Results typically begin within 2–4 days, with full effect at approximately 2 weeks.
Cost
Botox for hyperhidrosis is priced by the total units used:
- US pricing: $1,000–$1,500 per treatment session (both underarms) at 100 units total. Some clinics price per unit at $10–$15 per unit.
- Insurance coverage: Many insurance plans cover Botox for axillary hyperhidrosis when documented as medically necessary — typically requiring a trial and failure of prescription-strength antiperspirant (e.g., Drysol, Hypercare) first. Prior authorization is usually needed.
- Off-label areas: Palms, feet, and face treatments may not be covered by insurance and typically cost $1,000–$2,000 per session depending on the area and units required.
Alternative treatments for hyperhidrosis
Botox is not the only option. The treatment ladder for primary hyperhidrosis generally progresses as follows:
1. Prescription antiperspirants. Aluminum chloride 20% solutions (Drysol, Hypercare) are first-line. They work by physically blocking sweat ducts. Effective for mild cases, but can cause skin irritation and many patients find them insufficient.
2. Topical glycopyrronium. FDA-approved in 2018 (QBREXZA cloth), this anticholinergic wipe reduces sweating by blocking acetylcholine receptors topically. It avoids injections but can cause dry mouth and urinary retention in some patients.
3. Botox injections. As covered in this article — highly effective, well-studied, but temporary and requiring repeat treatments every 4–6 months.
4. Oral anticholinergics. Medications like glycopyrrolate reduce sweating systemically by blocking acetylcholine receptors throughout the body. Effective but can cause systemic side effects: dry mouth, blurred vision, urinary retention, constipation.
5. Iontophoresis. A device passes a mild electrical current through water to the affected area (typically hands or feet). Requires consistent at-home sessions. Mechanism is not fully understood but is believed to temporarily block sweat ducts.
6. Microwave thermolysis (miraDry). FDA-cleared device that uses microwave energy to permanently destroy underarm sweat glands. Typically requires 1–2 sessions. More expensive upfront ($2,000–$4,000) but provides longer-lasting results. Only approved for underarms.
7. Surgery (ETS). Endoscopic thoracic sympathectomy cuts or clamps the sympathetic nerve chain to stop sweating in targeted areas. Reserved for severe cases refractory to all other treatments. Risk of compensatory sweating (increased sweating elsewhere on the body) is significant and unpredictable.
Who should — and should not — get Botox for hyperhidrosis
Good candidates:
- Patients with severe primary axillary hyperhidrosis that has not responded to prescription antiperspirants
- Those seeking a non-surgical, temporary solution with high efficacy
- Patients who can commit to repeat treatments every 4–6 months
- Individuals with palmar or plantar hyperhidrosis who understand these are off-label uses
Not ideal for:
- Patients with secondary hyperhidrosis (the underlying condition should be treated first)
- Those allergic to botulinum toxin products
- Patients with active skin infections at the injection sites
- Individuals with neuromuscular disorders such as myasthenia gravis or Lambert-Eaton syndrome
- Pregnant or breastfeeding women (Botox is pregnancy category C)
- Patients seeking a permanent solution (consider miraDry or, in extreme cases, ETS)
Sources
Treatment of hyperhidrosis with Botox (onabotulinumtoxinA): development, insights, and impact. Medicine. 2023;102(S1):e32764. https://pmc.ncbi.nlm.nih.gov/articles/PMC10374185
Naumann MK, Hamm H, Lowe NJ, on behalf of the Botox Hyperhidrosis Clinical Study Group. Effect of botulinum toxin type A on quality of life measures in patients with primary axillary hyperhidrosis. Br J Dermatol. 2002;147(6):1218–1226. https://pubmed.ncbi.nlm.nih.gov/12452874
Li Y, Sun B, Lu J, et al. Botulinum toxin type A in the treatment of primary axillary hyperhidrosis: a phase 3, multicenter, randomized, double-blind, placebo-controlled study. Aesthet Surg J. Published online January 19, 2026. doi:10.1093/asj/sjaf260
FDA approval: Botox (onabotulinumtoxinA) for severe primary axillary hyperhidrosis. FDA Biologics License Application, 2004. https://www.fda.gov/drugs/novel-drug-approvals-fda
International Hyperhidrosis Society: Botox treatment overview. https://www.sweathelp.org/hyperhidrosis-treatments/botox.html
Baylor College of Medicine: Botox for excessive sweating. https://www.bcm.edu/healthcare/specialties/dermatology/excessive-sweating-options/botox-for-excessive-sweating
Aetna Clinical Policy Bulletin: Treatment of hyperhidrosis. https://www.aetna.com/cpb/medical/data/500_599/0504.html
