Botox for excessive sweating (hyperhidrosis): how it works, cost, and how long it lasts

Excessive sweating (hyperhidrosis) is one of the most underrecognized medical conditions that Botox treats highly effectively. It's FDA-approved for axillary (underarm) hyperhidrosis and used off-label for palms, feet, scalp, and forehead. For many patients, it's genuinely life-changing.

What hyperhidrosis is

Hyperhidrosis is sweating significantly in excess of what the body needs for temperature regulation. It affects approximately 3–5% of the population. Primary hyperhidrosis (not caused by another medical condition) is the most common form and typically affects the underarms, palms, feet, and/or scalp in focal, bilateral patterns.

Hyperhidrosis often begins in adolescence or young adulthood and can be triggered or worsened by stress, heat, and activity — but primary hyperhidrosis occurs even at rest and in cool environments, which distinguishes it from normal thermoregulatory sweating.

How Botox stops sweating

Botulinum toxin blocks the neurotransmitter acetylcholine at the neuromuscular junction. The same mechanism that relaxes muscles also blocks the cholinergic signals to sweat glands. When injected into the dermis (skin) rather than muscle, Botox prevents the sweat gland from receiving the signal to activate.

The sweat glands are physically intact — they simply don't receive the signal to produce sweat.

FDA clearance

Botox is FDA-approved for severe primary axillary hyperhidrosis in patients who fail topical treatments (prescription aluminum chloride, Drysol). This is a medical indication — covered by some insurance plans. Off-label uses for palms, feet, scalp, and face are not FDA-approved for this specific indication but are widely practiced with strong evidence.

Treatment areas and dosing

Underarms (axillary hyperhidrosis)

Most common and most evidence-supported use.

Procedure: A starch-iodine test maps the active sweat zones. Botox is injected via a grid pattern across the entire axilla — typically 10–20 injection points per side.

Dose: 50 units per underarm (100 units total) is the standard FDA-studied dose for Botox. Dysport equivalent: ~125 units per side.

Results: 80–90% reduction in sweating within 2 weeks. Results are often dramatic — patients describe it as life-changing for embarrassment from visible sweat marks.

Duration: 6–12 months (significantly longer than cosmetic Botox, because sweat glands are more susceptible to long-term effect than muscles).

Cost: $800–$1,500 for both underarms. Some insurance plans cover this treatment with prior authorization for medically severe cases.

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Palms (palmar hyperhidrosis)

Dose: 100 units per palm (200 units total). More units required because the thenar and hypothenar eminences are dense with sweat glands and the muscle tissue is extensive.

Procedure: Numbing is important here — the palms are very sensitive. Most providers offer nerve blocks (median and ulnar), topical anesthetic, or ice-based cooling. Ice alone is inadequate for most patients.

Important: Palmar Botox can cause temporary weakness in the intrinsic hand muscles (the small muscles that allow fine motor control). Patients should be counseled about this and avoid activities requiring fine motor work (surgery, certain instruments, detailed craft work) for 2–4 weeks post-treatment.

Duration: 3–6 months for palms (shorter than underarms; higher sweat gland density and more mechanical disruption).

Cost: $1,200–$2,500 for both palms (high unit count drives cost).

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Feet (plantar hyperhidrosis)

Similar to palms — extremely sensitive. Nerve blocks are essential. Doses are comparable.

Cost: $1,000–$2,000 for both feet.

Note: Foot sweat is a common cause of athlete's foot and secondary skin issues. Patients with recurrent fungal infections may see improvement with hyperhidrosis treatment.

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Scalp and forehead (craniofacial hyperhidrosis)

For patients who sweat heavily from the scalp or forehead — often disrupting hairstyles or causing visible dripping.

Dose: 50–100 units distributed across the target zone.

Duration: Similar to underarms, 6–12 months.

Cost: $600–$1,200.

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What the treatment experience is like

Underarms: The injection pattern is a grid approximately 1–2 cm apart across the sweating zone. Each injection is a small prick — the axilla is moderately sensitive. Most patients find it very tolerable, particularly with topical numbing cream applied beforehand. Total treatment time: 10–20 minutes per side.

Palms and feet: Significantly more uncomfortable without adequate anesthesia. Recommend asking specifically for nerve blocks if you're sensitive to pain.

After treatment: No restriction on activity. Some tenderness at injection sites for 1–3 days. You can use deodorant and shower normally.

When results appear

Underarm hyperhidrosis typically shows significant reduction at 1–2 weeks. Full effect at 2 weeks. Some patients notice improvement within days.

Palmar hyperhidrosis: similar timeline.

How long results last

| Area | Typical duration |
|---|---|
| Underarms | 6–12 months |
| Palms | 3–6 months |
| Feet | 3–6 months |
| Scalp/forehead | 6–12 months |

Sweat glands appear to respond more durably to repeated treatment than muscles do — some patients report increasing duration with each treatment over 2–3 years.

Insurance coverage

Severe primary axillary hyperhidrosis often qualifies for insurance coverage when:
The patient has failed topical treatments (documented trial of prescription aluminum chloride for at least 4 weeks)
The condition significantly impacts daily activities
A dermatologist or other qualified provider documents severity

If your provider is in-network and can document the above, prior authorization is often successful. Palmar and plantar hyperhidrosis coverage is more variable.

If pursuing insurance: Ask your provider if they bill insurance for this indication, and what documentation they need to submit.

Alternatives to Botox for hyperhidrosis

Topical treatments:
Prescription aluminum chloride (Drysol) — first-line treatment; effective for mild-moderate cases; needs to be the right concentration and application technique
Qbrexza (glycopyrronium cloth) — prescription topical anticholinergic; FDA-approved for primary axillary hyperhidrosis; once-daily wipe

Iontophoresis: A device that passes low-level electrical current through water into the skin — disrupts sweat gland function temporarily. Effective for palmar and plantar hyperhidrosis; requires daily sessions initially. Can rent or purchase device for at-home use.

miraDry: A permanent microwave energy device that destroys underarm sweat glands and hair follicles. Single treatment; permanent reduction. Cost: $2,000–$3,500. Only for underarms; not available for palms or feet.

Oral medications: Anticholinergics (glycopyrrolate, oxybutynin) reduce sweating systemically but have side effects (dry mouth, blurred vision, constipation).

Questions to ask before booking

Do you offer nerve blocks for palmar/plantar treatment, and what's the numbing protocol?
Do you accept insurance for axillary hyperhidrosis, and can you help with prior authorization?
What dose do you typically use for my treatment area, and is that the evidence-based dose?
How will you measure success — is there a follow-up assessment planned?
What do I do if I have only partial reduction at 2 weeks?

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