Excessive underarm sweating is more common than most people realize, and it can affect far more than clothing choices. People with it often avoid light colors, change shirts during the day, keep their arms close to their sides and worry about handshakes and hugs. Botox is one of the most effective treatments available for it, and it uses the same purified protein that softens frown lines, placed in a very different spot.

What causes heavy underarm sweating

Sweat glands are switched on by nerve signals. In most people they respond to heat, exercise and stress, and then settle. In people with primary hyperhidrosis, the nerves that drive the glands are overactive, so the glands produce far more sweat than the body needs to stay cool, often in a cool room while sitting still.

Primary hyperhidrosis tends to start in the teens or early adulthood, affects both sides evenly and often runs in families. Secondary hyperhidrosis is different: it is caused by something else, such as a medication, a hormonal change or a medical condition, and it is more likely to start later in life, affect the whole body or happen at night. That kind needs a medical assessment before any cosmetic treatment.

How underarm Botox works

Botox blocks the chemical message that nerves use to switch sweat glands on. Placed just under the skin of the underarm, it quietens the glands in that area, so they produce much less sweat. The glands themselves are not removed or damaged. They simply stop receiving the signal until the effect wears off and the nerve endings recover.

Botox is approved by the FDA for severe underarm sweating in adults when topical treatments have not worked well enough. Unlike Botox for lines, the injections are not placed into a muscle, which is part of why the effect behaves differently.

Who it suits

Good candidates are adults whose underarm sweating is heavy enough to soak through clothes or change how they live, and who have already tried a strong antiperspirant without enough success. It suits people who want a reliable result without surgery and without daily effort.

It is a poorer fit for someone whose sweating is mainly on the hands, feet or face, which need different approaches, or for anyone whose sweating has an underlying cause that has not been looked into.

Try these first

Most people start with a clinical strength antiperspirant containing aluminum chloride, applied to dry skin at night. Prescription wipes and creams are also available. If those do not control the sweating, or the skin becomes too irritated to keep using them, Botox is the usual next step. Some energy based devices are also used for underarm sweating, including fractional radiofrequency microneedling, which is discussed in the Morpheus8 cost guide.

The treatment

Underarm Botox is an office procedure. The area that sweats most is sometimes mapped first with a simple starch and iodine test, which turns dark where sweat appears. The skin is then treated with a grid of very fine, shallow injections across each underarm. The appointment is short, most people find it easy to tolerate, and you can return to normal activities the same day.

Arrive without antiperspirant or deodorant on, and avoid shaving the area for a day or two beforehand to reduce irritation. Afterwards, skip hot baths, saunas and hard exercise for the rest of the day. The Botox aftercare guide covers the general advice.

Results and how long they last

Most people notice a clear drop in sweating within a few days to two weeks. The effect usually lasts longer than Botox for lines, which typically wears off in three to four months. For sweating, many people stay noticeably drier for around six months, and some for longer. When sweating begins to return, the treatment is repeated. The guide to how long Botox lasts explains the factors that affect duration in general.

Safety and side effects

The most common effects are brief stinging during the injections, small bruises and mild tenderness, which settle within days. Some people notice slightly more sweating in other areas, though this is less common with Botox than after surgery to the sweat nerves. Because the injections are shallow and placed in the skin rather than a working muscle, arm strength is not affected. The underarms contain many sweat glands but only a small share of the body's total, so reducing them does not stop the body from cooling itself.

Anyone who is pregnant, breastfeeding or has a neuromuscular condition should not have Botox. A consultation also checks for signs that the sweating has another cause.

The short version

Underarm Botox reduces excessive sweating by blocking the nerve signal to the sweat glands in the treated skin. It is approved for severe underarm sweating, takes a short appointment, starts working within days to two weeks and often keeps the area drier for around six months. It works best after antiperspirants have been tried, and sweating that is new or widespread should be checked by a doctor first.

Tired of planning your clothes around sweat marks?

A consultation looks at how much you sweat, what you have already tried and whether anything else could be behind it, so you know whether underarm Botox is the right next step.

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It greatly reduces it for most people. Botox blocks the signal from the nerves to the sweat glands in the treated skin, so those glands produce much less sweat until the effect wears off. It treats the area that is injected, not the whole body.
Usually longer than Botox for lines. Many people stay noticeably drier for around six months, and some for longer. When sweating starts to return, the treatment can be repeated.
Botox is approved by the FDA for severe underarm sweating that has not responded to topical treatment. The underarm has many sweat glands but only accounts for a small share of the body's total, so it does not affect the body's ability to cool itself.
It involves a series of very fine injections just under the skin. Most people describe it as quick stings that are easy to tolerate, and the whole treatment takes only a short appointment.
Odor comes from bacteria breaking down sweat, so less sweat often means less odor. It is not a direct treatment for odor, though, and results vary from person to person.
Anyone pregnant, breastfeeding or with a neuromuscular condition should not have it. Sweating that is new, happens all over or comes with other symptoms should be checked by a doctor first.

Related reading: Botox in Beverly Hills, Botox aftercare, trap Botox, baby Botox, and how long Botox lasts.