What happens in
hair loss depends on its cause.
Inherited hair loss (androgenetic alopecia) is also called male-pattern hair loss or female-pattern hair loss. About half the population have some hair loss by about 50
years of age. Men may start losing hair between the ages of 15 and 25, and women are more likely to start losing hair between the ages of 25 and 30, or in some cases, after menopause.4
Men tend to lose hair on the front hairline and temples
and on top of the head. Eventually, they may go completely bald.
Women generally lose less hair than men, but they have a similar pattern of hair loss. Women may have slight, moderate, or even severe hair loss, but they don't usually lose all their hair.
For both men and women, this type of hair loss must be treated early for
hair to regrow.
See a picture of typical
inherited hair loss .
Other causes of hair loss
Alopecia areata is
hair loss caused when the immune system attacks
hair follicles , where hair growth begins. It usually starts with one or more
small, round, smooth bald patches on the scalp and can progress to total scalp
hair loss or complete body hair loss. It often begins in childhood. The hair
usually grows back within 1 year. But hair loss in alopecia areata often comes
and goes-the hair will grow back over several months in one area but will fall
out in another area.
Hair loss also may be caused by stress,
medicines or medical treatments. In these cases,
clumps of hair may fall out. But after the cause is stopped, the hair usually
grows back, although sometimes treatment may be needed.
Treatment to regrow hair does not work for everyone.
If your hair loss is inherited, treatment may not permanently restore your
hair. If your hair loss is caused by medicine, stress, or damage, hair often
grows back after the cause is removed, although sometimes you will need
For both men and women, hair thinning and baldness
increase the risk of sunburn and skin cancer on the scalp. When in the sun, it
is important to wear a hat or use a sunscreen with an SPF of 30 or more to
prevent sun damage to the scalp.