Dihydrotestosterone | DHT Hair Loss

DHT Hair Loss

This is the most common cause of thinning and affects both men and women. Men generally have hair loss concentrated in a specific pattern from the front through to the crown. Women tend to have thinning throughout their head without being in any specific pattern. This type of hair loss is caused by the androgen DHT, or Dihydrotestosterone. Since everyone has DHT that is produced by their bodies and only some people suffer from hair loss there has to be another factor involved. This other factor is having follicles that have a greater number of Androgen receptors for the DHT to attach to. This is the component that is inherited through the genes. To date the most effective preventative treatments are anti androgens, drugs that prevent the creation of DHT. In the future gene therapy will one day be able to alter the genes to prevent the follicles from being affected by DHT.

While the precise mechanism which underlies androgenic alopecia is unknown, a high level of dihydrotestosterone (DHT) is crucial in initiating the process. DHT is, ironically, a hair growth stimulator. DHT is formed from testosterone with the conversion from testosterone to DHT being mediated by 5-alpha reductase. There are two subtypes of 5-alpha reductase and drugs which block one type may not block the other.

While it's possible to find balding men who have similar androgen profiles to men with a full head of hair, people with more 5-alpha reductase or a greater density of DHT receptors may be more likely to have higher levels of DHT in their scalp, and be more affected by comparable levels of hormone there. Men with androgenic alopecia typically have lower levels of total testosterone, higher levels of unbound/free testosterone, and higher levels of total free androgens including DHT.

Spiking androgen levels, caused by intense weight training, sudden weight loss, taking anabolic steroids or other synthetic androgens and other causes can promote the balding process. The vast majority of anabolic steroids contribute to hair loss, since most anabolic compounds break down to form DHT at some point.

How DHT causes hair loss is hotly debated.

American research tends to focus on DHT, DHT receptor density in the scalp and 5-alpha reductase levels in the scalp as causes of baldness though the precise mechanism by which DHT causes baldness is not clear.

Japanese research may cover these topics but also is more likely to cover the increase in sebum (scalp oil) production caused by DHT in the scalp, and the increase of Pityrosporon ovale, a pathogenic yeast which has been linked to dandruff and eczema, and which feeds on sebum. Issues related to diet are also more likely to be covered. Possibly this is because male pattern baldness has increased very sharply in Japan since the end of World War II along with an increase in fatty foods and average height, focusing public attention on various lifestyle differences.

Most pharmaceutical treatments which stop or slow the balding process work by limiting the creation of DHT. In ideal situations this may cause a person's hairline to revert to what it was a year ago (since follicles which were resting but healthy will be active again), though it is difficult to reverse more than a year of hair loss without surgery.