Botox for Hyperhidrosis (Excessive Sweating): What to Expect

Medically reviewed by the clinical team at OC Weight Loss and Medspa. Last updated May 20, 2026.

Quick read: Botox is FDA-approved for severe primary axillary hyperhidrosis — excessive underarm sweating — that hasn’t responded to prescription antiperspirants. Standard dosing is 50 units per underarm, divided across 10 to 15 injection points. Results typically appear in 2 to 4 days, peak at 2 weeks, and last 4 to 6 months — often longer than cosmetic Botox in the face. Botox is also used off-label for palmar (hand) and plantar (foot) hyperhidrosis, with most insurers covering axillary treatment once documentation of failed topical therapy is in place.

What is hyperhidrosis?

Hyperhidrosis is sweating beyond what the body needs for thermoregulation. The condition affects roughly 5% of U.S. adults and is divided into two categories. Primary focal hyperhidrosis is the more common form — it starts in childhood or adolescence, runs in families, and affects specific areas: underarms (axillary), palms (palmar), soles (plantar), and face (craniofacial). Secondary hyperhidrosis is caused by an underlying condition — thyroid disorders, diabetes, menopause, medications — and is treated by addressing the cause.

Botox is approved for and most useful in primary focal hyperhidrosis. If your sweating is generalized (whole body), worse at night, or accompanied by weight loss, fever, or palpitations, that’s a flag for secondary hyperhidrosis and warrants a medical workup before considering injection therapy. For broader context on neurotoxin uses, see our neurotoxins guide.

How does Botox work for sweating?

Sweating is controlled by the sympathetic nervous system. When the brain signals a sweat response, nerve fibers release acetylcholine, which binds to receptors on eccrine sweat glands and triggers sweat production. Botox temporarily blocks the release of acetylcholine at those nerve terminals, which silences the signal and stops the gland from producing sweat.

The blockade is local — only the glands under the injected skin are affected. The body’s other sweat glands continue to function normally, which is why Botox for hyperhidrosis rarely causes problematic compensatory sweating elsewhere, despite the common misconception. Compensatory sweating is a known side effect of endoscopic thoracic sympathectomy (a surgical option for hyperhidrosis), not of Botox.

Where on the body does Botox work for hyperhidrosis?

The four primary treatment zones and their typical dosing:

• Underarms (axillary): 50 units per underarm. FDA-approved. Most common request.
• Palms (palmar): 50–100 units per palm. Off-label but well-established. More painful — requires regional nerve block or ice/topical anesthetic.
• Soles (plantar): 100 units per foot. Off-label. Painful; pre-treatment anesthesia is standard.
• Forehead / scalp (craniofacial): 50–100 units across the affected area. Off-label. Used selectively because of risk of brow drop if injection lines wander.

Axillary hyperhidrosis is the most predictable case — well-defined anatomy, FDA approval, insurance coverage, and the lowest discomfort during injection. Palmar and plantar treatments are effective but require more planning around pain control.

How is the treatment performed?

The injection workflow for axillary hyperhidrosis:

1. Mapping (optional but common): Some clinicians use the Minor’s starch-iodine test. Iodine is painted on the underarm, then dusted with starch; the starch turns dark blue-black where sweat is present. This maps the sweating zone precisely.
2. Skin marking: The injector divides the treatment zone into a grid of 10 to 15 points spaced about 1.5 to 2 cm apart.
3. Topical anesthesia: Underarm skin is fairly tolerant of injection, but some patients prefer a numbing cream applied 20–30 minutes beforehand.
4. Injection: 50 units of reconstituted Botox is delivered intradermally — just under the skin — across the marked grid, 2–5 units per injection point.
5. Post-care: A clean dressing if needed, normal activity afterward. No restrictions on showering or daily routine after a few hours.

The whole appointment for axillary treatment runs 30 to 45 minutes including consultation, mapping, and injection.

How long until you see results?

Most patients notice a clear reduction in sweating by day 2 to 4 after injection. Peak effect is at 2 weeks, with full assessment recommended at the 2-week mark before any touch-ups. Patients often describe the underarms going from “soaked through every shirt” to “essentially dry” — the result tends to be near-complete rather than partial when dosing is on target.

Duration of effect for hyperhidrosis is notably longer than for cosmetic facial Botox. In axillary hyperhidrosis, the median duration is 4 to 6 months, with some patients holding effect at 8 to 9 months. Palmar and plantar treatments tend to wear off faster — closer to 3 to 4 months — likely because of higher local metabolic activity and the larger sweat gland density in those areas.

If you’re used to the 3-to-4-month duration of forehead Botox, the longer hyperhidrosis effect is a real bonus. Many patients only need two treatments per year. For comparison with how facial dosing performs, see our guide to how long Botox lasts.

What does the research show?

Botox was FDA-approved for severe primary axillary hyperhidrosis in 2004 based on two phase 3 randomized controlled trials. In the pivotal trial, 81% of patients achieved at least a 50% reduction in sweat production at week 4, compared to 41% in the placebo group. Effect was maintained at 16 weeks in the majority of treated patients (Naumann et al., BMJ 2003).

Long-term safety data through multiple retreatment cycles is reassuring. A 16-month follow-up study of patients receiving repeated axillary injections found no decline in efficacy over multiple cycles and no significant safety signals. The current FDA prescribing information reflects more than two decades of cumulative experience with this indication (Botox prescribing information, FDA).

For palmar hyperhidrosis, evidence is strong but off-label. A 2012 systematic review confirmed that intradermal Botox is effective and well-tolerated for palmar sweating, though hand grip strength may decrease modestly in the first 2 to 3 weeks after injection.

Will insurance cover it?

For axillary hyperhidrosis, most commercial insurers and Medicare cover Botox with prior authorization. The standard requirements:

• Diagnosis of severe primary axillary hyperhidrosis (ICD-10 R61 or L74.5)
• Documented failure of, intolerance to, or contraindication to prescription-strength antiperspirants — typically aluminum chloride hexahydrate 20% (Drysol) used for at least 2 to 4 weeks
• Some plans also require failure of a trial of oral anticholinergic medication (glycopyrrolate, oxybutynin) or iontophoresis
• Treatment by a qualified provider — dermatologist or trained clinician familiar with the indication

Out-of-pocket cost without insurance is roughly $900 to $1,400 per session covering both underarms. Palmar treatment runs $1,200 to $1,800 because of the higher dose and added anesthesia time.

Palmar and plantar treatments are off-label and rarely covered by insurance, even when documentation of treatment failure is strong. Patients pay out of pocket in the majority of cases.

What are the side effects?

For axillary treatment, side effects are mostly mild and local:

• Injection-site soreness or bruising — usually fades in 24 to 72 hours
• Mild compensatory sweating on the trunk or face — uncommon, generally not problematic
• Brief flu-like symptoms in the first 24 hours — rare
• Itching in the treated area as effect kicks in — rare

For palmar treatment, the most reported adverse effect is temporary hand muscle weakness — patients may notice reduced grip strength or fine motor difficulty (buttoning a shirt, opening a jar) for 2 to 3 weeks. This resolves on its own and is usually not severe enough to interfere with daily life.

Contraindications are the same as for any Botox indication: known hypersensitivity, neuromuscular disorders (myasthenia gravis, Lambert-Eaton, ALS), pregnancy or breastfeeding, and active skin infection at the injection site. Patients on aminoglycoside antibiotics, anticholinergic medications, or muscle relaxants should disclose those — they can theoretically potentiate the effect.

For more on what to avoid before and after injection, see our masseter Botox guide — the post-procedure precautions are similar across all medical Botox uses.

Who is a good candidate?

Botox for hyperhidrosis is a good fit when:

• You have severe focal sweating — clothing damage, daily interference with work or social activities, anxiety around handshakes or presentations
• You’ve tried prescription antiperspirants without sufficient relief
• You want a non-permanent option — Botox is reversible and reassesses every 4 to 6 months
• You want to avoid the systemic side effects of oral anticholinergics (dry mouth, blurred vision, urinary retention)
• You’re not a candidate for or don’t want to consider miraDry, sympathectomy, or other more permanent procedures

FAQ

Talk to a clinician at OC Weight Loss and Medspa

If excessive sweating is interfering with your work, social life, or confidence, Botox is one of the most predictable treatments available — particularly for the underarms. Our team can walk you through dosing, pricing, what your insurance is likely to cover, and what realistic results look like. Review our Botox service page for more on indications and options.

Book a free consultation

Sources: Naumann M, Lowe NJ, BMJ 2003 (pivotal axillary hyperhidrosis trial); Botox (onabotulinumtoxinA) FDA prescribing information; International Hyperhidrosis Society clinical guidelines. Reviewed for clinical accuracy by the OC Weight Loss and Medspa injection team.