miraDry is a microwave treatment for underarm sweating, the condition doctors call primary axillary hyperhidrosis. A handpiece held to the skin draws the underarm skin in by suction and sends microwave energy to the junction between the skin and the fat beneath it, which the manufacturer describes as where the sweat glands reside. The energy heats that layer enough to destroy the glands while a cooling plate protects the surface, and the manufacturer says the destroyed glands do not grow back. It has been FDA-cleared in the US for primary axillary hyperhidrosis since 2011, for underarm hair reduction since 2015 and, with the wording that it may reduce underarm odour, since 2016. One or two sessions of about an hour to ninety minutes, under local anaesthetic, at Sweat Hospital, 130 Harley Street.
Why heat, and why the underarm
Injections switch the glands off for months; miraDry destroys them. Microwave energy is absorbed by water, and the sweat glands and the tissue around them are water-rich, so the energy heats that layer selectively while the cooling keeps the skin surface itself below the temperature that would harm it. The underarm is the one area it is cleared for. The manufacturer says it is not indicated for any other body area or for generalised sweating, and we do not treat any other area.
The session
- Before: shave the underarms four to six days before, so a little regrowth shows the area to be treated.
- Marking: a temporary template transfers a grid onto each underarm, so each placement of the handpiece follows the grid.
- Anaesthetic: local anaesthetic is given in several small injections across each underarm, and the clinician waits at least ten minutes for it to work.
- Treatment: the handpiece is placed on each square of the grid in turn; suction draws the skin in, the energy runs, the cooling runs, and the handpiece moves on. Up to 20 minutes per underarm; about an hour to ninety minutes in all with the preparation.
- After: ice on the underarms for the first day or two, loose clothing, and no vigorous exercise for about three days. Most people are at work the next day in our experience.
The manufacturer's manual recommends its lowest energy setting for a first session; a second session, where the review shows it is needed, comes about three months later. The sessions page explains how that is decided.
What the studies measured
The randomised trial compared 120 adults with severe underarm sweating against a sham treatment. At 30 days 89% of the treated group rated their sweating never noticeable or tolerable, against 54% of the sham group; 74% did at three months and 69% at twelve. In a study of 31 adults without a comparison group, sweat collected and weighed was 83% lower at 30 days and 82% lower on average at twelve months. Two follow-up surveys found the improvement still there at about three years, and a 2024 trial that treated one underarm with each found the microwave treatment matched botulinum toxin injections on weighed sweat at one year. The how long it lasts page sets out each study.
Hair and odour
The manufacturer says the treatment also destroys the hair follicles in the underarm, so it reduces underarm hair as well: in the US clearance study of 56 adults, the hair count was 75% lower on average at twelve months and stable from six months on, on fair to olive skin (types I to IV). The heat also reaches the odour-producing glands, which sit in the same layer as the sweat glands, and in the 31-adult study the share of patients who said their odour was not noticeable rose from 13% to between 61% and 74%; a separate odour trial did not reach its main goal, which is why the clearance wording is only that it may reduce odour.
Who it is for, and who it is not for
Adults with underarm sweating that antiperspirants have not controlled, whether it soaks shirts, embarrasses or simply will not stop. It is not for anyone with a pacemaker or another electronic implant, anyone on supplemental oxygen, or anyone who cannot have local anaesthetic. Pregnancy and the darkest skin type have not been tested. The manual also discourages treatment in pregnancy and after surgery in the armpit, asks for specialist medical advice before treating anyone with a metal implant, and calls for caution with very little fat under the skin and in anyone who is immunocompromised or heals poorly. Hands, feet, face, back and chest are not cleared areas and are not treated. The downsides page gives the risks with their figures. NICE's 2017 guidance asks clinics to tell patients about the nerve risk, and we do that in writing.
Book a free consultation
Call Sweat Hospital on 0207 043 1116 or use the form below. The clinician scores your sweating on the standard four-point scale, checks the list above, and gives you the plan and the price in writing. The full miraDry guide covers the rest.
