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NHS Choices Condition

Content supplied by NHS Choices

The human head has on average 100,000 hairs. Hair is made in hair follicles, the roots of the hair. Each hair grows for about three years, then it drops out and a new one grows. We lose 40-120 hairs a day.


Male-pattern and female-pattern baldness is caused by oversensitive hair follicles. This is linked to the hormone dihydrotestosterone (DHT), which is made from the male hormone testosterone. If there is too much DHT, the follicles react to it and the hair becomes thinner and grows for less time than normal. The balding process is gradual because different follicles are affected at different times.

Immune system imbalance

Alopecia areata is linked to an imbalance in the immune system. The hair follicles are not permanently damaged, and in many cases the hair grows back in a few months. It runs in the family in one in five cases.

Other causes

Some conditions such as anaemia (disorder of the blood), illness, stress (including bereavement), fungal infections and thyroid problems can make you lose some of your hair, as well as drug treatment for cancer. Women who are pregnant or have recently given birth may also experience some hair loss.

view information about Hair loss on www.nhs.co.uk »

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