What is smegma?

Smegma is a whitish substance that may be present on the genitalia. It is caused by the shedding of skin cells and it is harmless, although it may become problematic if it is allowed to build up. (1, 2, 9)

Smegma in males: where does it occur?

Smegma occurs on the head of the penis, also known as the penis glans, and under the foreskin. (3)

Smegma in females: where does it occur?

In females, smegma is found between the labia, the lips which protect the vagina, and around the clitoral hood, which is at the top of the labia minora. (4, 5)

What causes smegma?

Smegma is caused by shredded skin cells, largely dead epithelial cells, mixing with skin oil secretions, such as sweat and naturally-produced lubricants. (4, 8, 10)

Smegma may build up if it is not washed away. This may cause problems, thus good personal hygiene is necessary to avoid such problems. (8)

Problems with smegma build up

If smegma is allowed to build up it may begin to smell. It also may provide a place where bacteria can breed. (6)

In males, smegma can also cause the foreskin to stick to the head of the penis. This may make erections painful as the foreskin cannot be easily rolled back. (6, 7)

A similar problem may occur in females. If there is a build-up of smegma, the clitoral hood may stick to the shaft and glans of the clitoris. This also may be painful. (13)

Furthermore, a build-up of smegma in males may cause a condition called balanitis. This is where the head of the penis becomes inflamed. (3) Other symptoms of balanitis include an unpleasant -smelling discharge. (15) Balanitis is common and is, in fact, the reason why 1 in 10 men attend a sexual health clinic. (11)

Prevention of smegma build up

Smegma can be prevented by washing the genitals with warm water at least once a day. This applies to both males and females. (4, 8)

It is particularly important for uncircumcised males to wash underneath their foreskin, as this is where smegma can build up. (8)

Despite the advice of regular washing, the NHS advise that you do not wash your genitals with strongly-perfumed soap or shower gel, or use deodorants or other such products, as this may lead to irritation. (8)

Smegma and cancer

Some studies have indicated a possibility that smegma may contain cancer-causing substances. They do state, however, that this link has not been proven. (12)

According to the American Cancer Society it is now mainly believed that smegma itself is probably not responsible for penile cancer, but that it could potentially increase the risk of cancer by causing irritation of the penis. (14)

Smegma in children

Smegma is found particularly in young boys. This is because the penis undergoes a change where the foreskin detaches from the head of the penis. This change requires skin cells to be shed. These skin cells may form smegma.

This change can occur at various ages; however, it tends to occur before the age of 5. The change may, however, occur earlier – even before birth or shortly after – or later – around the teenage years.

It is important not to force the foreskin back in order to remove smegma. This can damage the penis in the following ways:

• It may cause pain
• It may cause bleeding
• It may cause tears in the skin
• It may lead to scars (16, 17)