Hyperhidrosis (excessive sweating)

The AAD reports results lasting 3 to 10 months in the underarms or hands, 3 to 6 months for the feet and around four and a half months for the face. Most people notice the effect within 7 to 10 days. It is repeated when the clinical effect diminishes, not on a fixed calendar.

Increased sweating at untreated sites is listed as an adverse reaction on the axillary botulinum toxin label, but it is usually minor. It is a far larger problem after endoscopic thoracic sympathectomy, where a 2025 meta-analysis of 3,117 patients found compensatory hyperhidrosis in 62% and severe compensatory hyperhidrosis in 23%. That is the main reason surgery is kept for refractory cases.

Microwave thermolysis destroys sweat glands rather than blocking them, so the reduction is long-lasting. In the randomised sham-controlled trial, responder rates held from 74% at three months to 69% at twelve months, where follow-up ended. Most protocols use one or two sessions, and a 2024 randomised trial found it matched botulinum toxin for sweat reduction at one year while also reducing underarm odour and hair.

Yes, but the evidence and the licence differ. Botulinum toxin approval covers severe primary axillary hyperhidrosis only, and safety and effectiveness in other body areas have not been established, so palmar and plantar injection is off-label and we consent it as such. For hands and feet, iontophoresis — a weak electric current passed through water — is a well-established first-line option, usually 20-30 minute sessions repeated over 5 to 10 treatments with weekly or fortnightly maintenance.

Underarm injections are brief stinging across 10-15 shallow points, and injection-site pain with small bleeding points is the most commonly reported reaction. Palmar and plantar injections are more uncomfortable and are done with topical anaesthetic, ice or a nerve block. Microwave thermolysis is performed under local anaesthetic infiltrated into the underarm. The sting lasts only as long as each injection; what follows is mild tenderness at the injection points over the first 24 to 48 hours, and it settles on its own — there is no dressing and no recovery to manage.

It is excluded in neuromuscular disorders such as myasthenia gravis or ALS, where the effect at the neuromuscular junction is unpredictable and can be amplified. It is deferred through pregnancy and breastfeeding, in line with international guidance on cosmetic injectables. And it is not injected through active skin infection, open wounds or an eczema flare in the treatment area — that waits until the skin has healed.

Hyperhidrosis is sweating in excess of what the body needs to cool down, and it can happen at rest or in cold conditions. The NHS suggests seeing a doctor when excessive sweating has lasted at least six months, occurs at least weekly, interferes with daily life, or when there is night sweating or a family history. A clinician can confirm the pattern and rule out an underlying cause.

Volume alone does not settle it — in heat or hard exercise, losses of roughly half a litre to two litres an hour are ordinary. Hyperhidrosis is defined by the mismatch rather than the amount: sweating at rest, in cool conditions, or far beyond what cooling requires, in a fixed focal pattern. That is why severity is graded on the Hyperhidrosis Disease Severity Scale and the sweat weighed gravimetrically where that is used, instead of asking you to estimate.

Prescription-strength aluminium chloride antiperspirant applied at night to dry skin is the standard first step. Topical anticholinergics — glycopyrronium cloth 2.4%, approved for primary axillary hyperhidrosis from age 9, and sofpironium gel — are applied once daily. Oral glycopyrronium or oxybutynin reduce sweating body-wide, and propranolol is used for situational, anxiety-driven sweating. Simple measures help alongside any of these: breathable natural fabrics such as cotton, silk or wool, frequent showering, changing socks once or twice a day to keep the feet dry, and staying hydrated so body temperature is easier to regulate.

Not in the way the question hopes. Staying hydrated helps the body regulate its temperature, so it is less likely to climb to the point where thermal sweating is triggered — which is why it sits on the list of simple measures alongside breathable fabrics and changing socks. But primary focal hyperhidrosis is sweating that happens at rest and in cool conditions, independent of what cooling actually requires, so no amount of water switches it off. Hydration supports the treatment; it does not replace it.

Honestly, that depends on what it costs you at home. This is sold per session, not as a cure — in a 15-year cohort of 117 patients, median duration was 6 months after the first injection and 8 months after later ones, so it means roughly one to two trips a year unless you arrange maintenance with a physician near you. Combining it with another reason to travel usually makes more sense than flying for the injection alone.

Sweating that arrives together with chest pain, nausea or lightheadedness is not a hyperhidrosis question — that combination can signal an acute cardiac or other medical problem and needs immediate attention, not a clinic appointment. Hyperhidrosis itself is diagnosed around a chronic pattern; anything sudden and systemic should be assessed urgently first.

Constantly damp skin softens and breaks down — cracked or wrinkled (macerated) skin — and becomes more prone to bacterial and fungal infection, itching and persistent odour. None of these are dangerous in themselves, but together with the effect on work, grip and social life they are the practical reasons the condition is treated rather than tolerated.

Usually, indirectly. Underarm odour comes from skin bacteria breaking down secretion on damp skin, so taking away the moisture they work in reduces it, and people tend to notice the smell easing alongside the wetness. It is not a deodorising treatment, though — if odour rather than sweat is the main complaint, say so at consultation, because it changes which option makes sense.

Yes. Local sweat gland removal — surgical excision, suction curettage through a small incision, or laser ablation — physically destroys underarm glands, so the effect on the treated glands is permanent. These techniques sit alongside microwave thermolysis as gland-destroying options, but they involve incisions, possible scarring and a longer recovery, so they are discussed case by case rather than offered as a first-line step.