Body odour, also known as bromhidrosis, is the unpleasant smell that can occur when you sweat.
The sweat itself does not smell. The unpleasant odour is produced by bacteria on the skin that break down the sweat into acids.
There are 3-4 million sweat glands on the human body. The two types of sweat gland are:
- eccrine glands - which are spread across the skin and regulate body temperature by cooling the skin with sweat when you get hot
- apocrine glands - mainly found in hairy areas of the body, such as the armpits and genital area; apocrine glands develop during puberty and release scented chemicals called pheromones
Sweat produced by the eccrine glands is usually odourless, although it can smell if bacteria start to break it down.
It can also take on an offensive odour if you consume certain food and drink, such as garlic, spices and alcohol, as well as some types of medication, such as antidepressants.
However, it is the apocrine glands that are mainly responsible for body odour because the sweat they produce contains high levels of protein, which bacteria find easy to break down.
People who sweat excessively from their apocrine glands, or have a lot of bacteria on their skin, tend to have worse body odour.
Who gets body odour?
Anyone who has reached puberty (when the apocrine sweat glands develop) can produce body odour. As men tend to sweat more than women, they are more likely to have body odour.
Things that can make body odour worse include:
- being overweight
- eating rich or spicy foods
- certain medical conditions, such as diabetes
Managing body odour
The best way to avoid getting body odour is to keep areas of your body prone to sweating clean and free of bacteria.
Use soap to wash every day, paying particular attention to areas that sweat most, such as armpits, genital area and feet. Washing removes sweat and reduces the number of bacteria on your skin.
Changing your clothes and socks on a regular basis will also help. You should wash your clothes regularly.
Using an antiperspirant or deodorant daily will also help prevent body odour. Antiperspirants work by reducing the amount of sweat your body produces. Deodorants use perfume to mask the smell of sweat.
Regularly shaving your armpits can also help reduce body odour. The hair in your armpits traps sweat and odour and provides ideal conditions for bacteria to multiply.
In severe cases of body odour, surgery or treatment with botulinum toxin may be possible options.
Read more about how to treat body odour.
Excessive sweating and body odour is an unpleasant problem that can affect a person's confidence and self-esteem.
A body odour problem can usually be managed by:
- getting rid of excess skin bacteria, which are responsible for the smell
- keeping the skin in the affected area (usually the armpits) clean and dry
Self care advice
Your armpits contain a large number of apocrine glands, which are responsible for producing body odour. Keeping your armpits clean and free of bacteria will help keep odour under control.
- Take a warm bath or shower once a day. This will help kill the bacteria on your skin. On hot days, you may need to bath or shower twice a day.
- Wash your armpits thoroughly using an antibacterial soap.
- Use a deodorant or an antiperspirant after bathing or showering.
- Regularly shaving your armpits will allow sweat to evaporate quicker, giving bacteria less time to break it down.
- Wear natural fibres, such as wool, silk or cotton. They allow your skin to breathe, which means your sweat will evaporate quicker.
- Wear clean clothes and make sure you wash your clothes regularly.
- Limit your consumption of spicy foods, such as curry or garlic, because they can make your sweat smell. Evidence also suggests that eating a lot of red meat tends to make body odour worse.
Aluminium chloride is the active ingredient in most antiperspirants. It helps prevent production of sweat.
If the above self care advice does not improve your body odour, you may need a stronger antiperspirant that contains more aluminium chloride.
Your doctor or pharmacist can recommend a suitable product and advise about how often you should use it.
Aluminium chloride solutions are usually applied every night before bed, and 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 aluminium chloride solution begins to take effect, you can use it less often (every other night or once or twice a week).
Surgery may be recommended for severe body odour that cannot be treated by self-care measures and over-the-counter products.
One type of surgery involves removing a small area of skin from your armpit and the tissue just below it. This will get rid of the most troublesome sweat glands.
It may also be possible for the sweat glands to be drawn out from the deeper skin layers using liposuction (a technique often used to remove unwanted body fat).
Another option is a type of surgery called endoscopic thoracic sympathectomy (ETS), which uses keyhole surgery to destroy the nerves that control sweating.
During ETS, the surgeon will make two or three small incisions under each arm. A tiny camera (endoscope) will be inserted through one of the incisions so the surgeon can see the inside of your armpit on a monitor.
The surgeon will insert small surgical tools through the other incisions, allowing them to cut the nerves. Alternatively, a thin electrode that emits an electrical current will be used to destroy the nerves.
Risks associated with ETS include damage to nearby arteries or nerves and compensatory sweating (increased sweating from other areas of the body). You should fully discuss the risks of the procedure with your surgeon.
Read more about how excessive sweating is treated.
[Botulinum toxin], often referred to as Botox, is another possible treatment for people with excessive underarm sweating.
Botulinum toxin is a powerful poison that can be used safely in minute doses. Between 12-20 injections of botulinum toxin are made in the affected area of the body, such as the armpits, hands, feet or face.
The toxin works by blocking signals from your brain to the sweat glands, reducing the amount of sweat produced. The procedure takes 30-45 minutes, and the effects of botulinum toxin usually last 2-8 months. After this time, further treatment will be needed. You may need to visit a private cosmetic clinic for treatment. Prices can vary, depending on the area of the body being treated. Make sure you find out the cost before you start treatment.