Testosterone Related Diseases Baldness

Baldness is quite common in men, but men who do not produce testosterone (as the result of a medical condition or castration) do not go bald. This observation was an early clue to medical researchers that testosterone had something to do with male baldness.

How Testosterone Affects Hair Growth

As boys reach adolescence, testosterone levels rise, setting off a series of physical changes that includes the growth of hair on the face and body. Women who experience a rise in testosterone levels also often see increased facial and body hair. However, testosterone affects hair growth on the head very differently than it does hair growth elsewhere on the body.

When testosterone comes into contact with the enzyme 5-alpha-reductase, an enzyme found in the cells of hair follicles of the scalp, it is converted into dihydrotestosterone (DHT). This testosterone derivative affects hair growth by binding to receptors within the hair follicle cells. When this occurs, the hair follicle is induced to produce hairs that are thinner and more prone to falling out than normal hairs.

Male Pattern Baldness and Testosterone - Testosterone and Baldness

Male Pattern Baldness

The most common type of genetic baldness is “androgenetic alopecia,” also known in men as “male pattern baldness.” A receding hairline and thinning hair at the crown characterizes this type of baldness. Around 25 percent of all men start to show signs of male pattern baldness by age 30, and this number more than doubles by age 60. However, although age is a major factor in the progression of androgenetic alopecia, the primary cause is genetic. That is, the condition is inherited at birth and eventually expressed later in life.

The gene that confers pattern baldness causes the hair follicles at the hairline and crown to be especially sensitive to DHT. Thus, even a normal level of DHT production will cause baldness in a man who carries the male pattern baldness gene. The result is the production of fine hairs that quickly fall out.

A misconception about pattern baldness is that it can only be passed from mother to son. In fact, it can be inherited from either parent, although the mother’s genetic contribution may play a slightly more significant role.

Baldness in Women

Women can also develop pattern baldness. The hair loss tends to be a more uniform hair loss across the scalp, rather than a receding hairline or thinning that is confined to the crown. Because women have lower levels of testosterone than men, female pattern baldness is less common than male baldness.

For women, non-genetic causes of baldness are probably more common than female pattern baldness. Pregnancy, child birth and oral contraceptives have all been known to promote temporary hair loss in some women.


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