This is also known as alopecia androgenetica or androgenetic alopecia and is the commonest cause for hair loss in humans. There are variations in men and women. This condition is also found in orangutans and chimpanzees. The usual pattern is loss of hair in a distinct pattern starting above each temple.
The hair simultaneously begins to thin at the crown of the head and the hair may form a rim around the sides and the back of the head. Androgenic hair loss is also known as “Hippocratic balding”. Women suffer a different pattern which is never complete baldness but manifests itself in the form of thinning of the hair over the entire scalp. It is known as “female pattern baldness” and rarely results in complete baldness.
There are several genetic and also environmental causes for androgenic hair loss. Much research has been carried out in an attempt to understand the causes of androgenic hair loss. One of the causes is believed to be the presence of hormones known as androgens.
One particular category of such hormones is dihydrotestosterone (DHT). This hormone is particularly prevalent during the prenatal stage in the life of a male and also during puberty. DHT has an adverse effect on the hair follicles causing them to shrink. This in turn inhibits the growth of new hair and eventually, the old hair begins to fall out.
There is a lot of research going on concerning the genetic aspect of androgenic hair loss. It is believed that this is largely linked to X-chromosomes. The conclusion of this research is that men who had fathers who had experienced hair loss have two-and-a-half times more chance of experiencing hair loss than others, with no reference to their mother’s family. Several genes have been identified which have association with baldness. Some of them are EDA2R, P2RY5 and SOX21.
Androgenic hair loss has a direct relationship with hormone levels in the human body. Therefore when there is a hormone balance such as during puberty, pregnancy and menopause, there is a likelihood of developing this type of hair loss or one of its many manifestations. As mentioned above, hormones like DHT contribute a lot to androgenic hair loss.
Hormones and genetics play a major role in the process of androgenic hair loss. However, lifestyle also has a considerable role to play. One of the most popular examples is the occurrence of female and male pattern baldness in post-World War II Japan. This form of baldness was not known in such societies previously but it is believed that changes in the lifestyle in post-war Japan were largely the cause of hair loss in both men and women.
As a result of the above discussion on the causes of androgenic hair loss, one should be able to understand it better and tackle the problem in the early stages.