Hyperhidrosis: A GP’s Guide to Excessive Sweating and How It Is Treated

By Dr Amber Halliday, MRCGP MBBS BSc (Hons) | Blue Bird Aesthetics, Worthing
✓ Medically reviewed by Dr Amber Halliday, MRCGP MBBS BSc (Hons)

This is a medical condition, not a personal failing

Most people I treat for excessive underarm sweating have been managing it privately for years. They have built routines around it — the spare shirt, the specific fabrics, the seat at the end of the row, the avoidance of light colours and of raising their arms. Many have never raised it with a doctor because they assumed it was simply how they are.

Primary focal hyperhidrosis is a recognised condition in which the sweat glands are overstimulated by the sympathetic nervous system, producing sweat far in excess of what thermoregulation requires. It happens regardless of temperature, exertion or anxiety, although anxiety about it understandably makes it worse. It commonly begins in adolescence and it runs in families.

It is underdiagnosed because people rarely present with it. That is the main barrier — not the availability of effective treatment.

Primary or secondary — the assessment that comes first

Before treating anyone for excessive sweating I need to establish which type it is, because the answer changes what should happen next.

Primary focal hyperhidrosis is localised — underarms, palms, soles, sometimes the face — typically symmetrical, present since adolescence or early adulthood, and absent during sleep. This is the type that responds well to injectable treatment.

Secondary hyperhidrosis is generalised, may occur at night, and has an underlying cause. Possible causes include thyroid overactivity, diabetes and hypoglycaemic episodes, menopause, infection, certain medications including some antidepressants, and less commonly some haematological conditions. Treating the sweating cosmetically without investigating the cause would be poor medicine.

What treatment involves

Treatment uses a prescription medicine injected into the skin of the underarm. It works by blocking the chemical signal travelling from the nerve endings to the sweat glands. The glands themselves are unaffected and undamaged; they simply stop receiving the instruction to produce sweat.

Practically: the area is mapped, topical numbing is applied, and a grid of small superficial injections is administered across each underarm. The injections are shallow and most people find them very manageable. The appointment takes around 45 minutes including assessment.

What to expect afterwards

• Onset: a reduction begins within three to seven days and reaches full effect at around two weeks.
• Downtime: none. Mild tenderness or small bumps at the injection sites settle within hours.
• Aftercare: avoid antiperspirant, hot baths, saunas and heavy exercise for 24 hours. Shaving is best avoided for a couple of days.
• Duration: typically six to twelve months. Most patients settle into a pattern of one treatment a year, sometimes timed ahead of summer.

That duration is notably longer than the three to four months the same class of treatment gives when used cosmetically on the face. The reason is that the target here is a different type of nerve ending supplying a gland, rather than a large, constantly contracting muscle.

Does it stop you sweating elsewhere?

No. The effect is entirely local to the treated area. Your body continues to thermoregulate normally through the millions of sweat glands elsewhere. There is no evidence of compensatory excessive sweating developing elsewhere after underarm treatment — that phenomenon is associated with surgical sympathectomy, which is a very different intervention.

Who it is not for

• Suspected secondary hyperhidrosis where the underlying cause has not been investigated
• Pregnancy or breastfeeding
• Certain neuromuscular conditions, including myasthenia gravis and Lambert-Eaton syndrome
• Active infection or skin disease in the treatment area
• Known sensitivity to the medicine or its components

Palms and soles can also be treated but are more complex, more uncomfortable and carry a risk of transient grip weakness. That is a separate conversation and I assess it individually.

What to try before injectable treatment

I would rather you had tried the simpler options first, both because they sometimes work and because it strengthens the case if you later pursue NHS funding.

• A proper antiperspirant containing aluminium chloride — not a deodorant. Applied at night to completely dry skin, not in the morning after a shower. This is the single most common mistake and it makes the difference between the product working and not.
• Clothing choices — natural fibres and underarm shields help manage the consequences even though they do nothing for the cause.
• Reviewing your medications with your GP if you take anything that could contribute.

If those have genuinely been tried and have not worked, injectable treatment is a reasonable and evidence-supported next step.

Frequently Asked Questions

Ready to look at pricing and book? The underarm sweating treatment page has the detail. The consultation and safety page explains how suitability is assessed before any injectable treatment.

Related reading: Underarm Sweating — treatment page  ·  Excessive Sweating — Skin Concerns  ·  How Anti-Wrinkle Injections Work  ·  Why a Prescriber Matters in Aesthetics  ·  Aesthetic Treatments for Men  ·  What Happens at Your First Consultation

This article is for information only and does not constitute medical advice. Individual suitability can only be assessed in person. All treatments at Blue Bird Aesthetics are subject to medical consultation and go ahead only when clinically appropriate.