Body odour, also known as bromhidrosis, is the unpleasant smell that can occur when you sweat. Human sweat is mostly odourless, but when bacteria on the skin break down the sweat into acids, it produces an unpleasant smell.

Sweat glands

The human body contains 3-4 million sweat glands. There are two types of gland:

• eccrine glands – spread across your skin, these are responsible for regulating your body's temperature by cooling your skin with sweat when you get hot
• apocrine glands – concentrated in your armpits, genital area and breasts, these glands develop during puberty and release scented chemicals known as pheromones

Eccrine sweat is usually odourless but can start to smell if bacteria get a chance to break down the stale sweat. It can also take on an offensive odour if you consume certain things, such as garlic, spices, alcohol and certain medications, such as some antidepressants.

But it is the apocrine glands that are mostly responsible for body odour because the sweat that they produce contains a high level of protein, which bacteria find easy to break down. Body odour is worse if you have a high level of apocrine sweat production, or there is lots of bacteria on your skin.

Who is affected

Everyone who has passed the age of puberty (and therefore developed apocrine glands) can produce body odour.

Factors that can make body odour worse include:

• being overweight
• eating a diet rich in spicy foods
• having certain medical conditions, such as diabetes (see the Body odour warning sign box in Body odour - treatment)

Men tend to sweat more than women and are more likely to have body odour.

Managing body odour

You can manage a body odour problem by getting rid of any excess skin bacteria and keeping the affected skin as dry as possible. This can often be achieved through simple hygiene measures.

Surgery is available for more severe sweating that cannot be treated by self-care measures and over-the-counter products. See Body odour – treatment for more information.

A body odour problem can be managed by:

• getting rid of any excess skin bacteria, which are responsible for the smell
• keeping the skin in the affected area (often the armpits) as dry as possible

The below advice focuses on managing armpit odour, the most common problem.

Self-care advice

Your armpits contain a large concentration of apocrine glands. Keeping them clean and free of bacteria can help to keep odour under control.

• Take a bath or shower once a day. The warm water will help to kill the bacteria on your skin. On hot days, you may want to consider bathing or showering twice a day.
• Wash your armpits thoroughly with an antibacterial soap.
• Use a deodorant or an antiperspirant after bathing or showering (see box).
• Shave your armpits regularly so that the sweat evaporates quicker, giving the bacteria less time to break it down.
• Wear natural-made fibres, such as wool, silk or cotton. They will allow your skin to breathe, which means your sweat will evaporate quicker.
• Limit your consumption of spicy foods, such as curry or garlic, because they can make your sweat smell. There is also evidence that people who eat a lot of red meat tend to have worse body odour.

Aluminium chloride

Aluminium chloride is the active ingredient in most antiperspirants. It helps to prevent the production of sweat (see box, above right).

If the above self-care advice does not improve your body odour, you may need to use a stronger antiperspirant that contains more aluminium chloride.

Examples of aluminium chloride solutions include Anhydrol Forte and Driclor. These are usually applied every night before you go to bed, then washed off in the morning. This is because you stop sweating in your sleep, so the solution can seep into your sweat glands and block them. This reduces how much you sweat the next day.

As the product starts to take effect, you can use it less often – every other night or once or twice a week. Your GP or pharmacist will recommend a suitable product and how often you should use it.

Surgery

There are surgical options for severe sweating that cannot be treated by self-care measures and over-the-counter products.

A small area of skin and the tissue just below it can be removed from the armpit. This destroys the most troublesome sweat glands. Sometimes, the sweat glands can be drawn out from the deeper layers of skin using liposuction.

Another option is a type of surgery called endoscopic thoracic sympathectomy, which uses keyhole surgery to destroy the nerves that control sweating. A tiny incision (cut) is made into your underarm, through which a thin electrode is passed and electrical current used to kill off the nerves.

For more information on surgical treatments for excessive sweating, see the Health A-Z page on treating hyperhidrosis.

Botulinum toxin

Botulinum toxin, commonly known as Botox, is a relatively new treatment for people with excessive underarm sweating.

Botulinum toxin is a powerful poison that can be used safely in minute doses. Around 12 injections of botulinum toxin are given in the affected areas of the body, such as the armpits, hands, feet or face. The procedure takes about 30 to 45 minutes. The toxin works by blocking the signals from the brain to the sweat glands, reducing the amount of sweat produced.

The effects of botulinum toxin usually last from two to eight months. After this time, further treatment is needed.

Treatment with botulinum toxin is not usually available on the NHS. You may need to visit a private cosmetic clinic. Prices can vary, so make sure you find out the cost before you start treatment.