Male pattern baldness (named also androgenetic alopecia, alopecia androgenetica, androgenic alopecia) is loosing hair because of a phenomenon named miniaturization: under the influence of one’s own hormones the hair follicles become progressively smaller and eventually disappear. The culprit is DHT, or Dihydrotestosterone, which is a sex steroid and androgen hormone. DHT miniaturizes hair follicles by shortening the anagen (growth) phase and/or lengthening the telogen (resting) phase – see more about hair growing cycles.
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.
It is the most common cause of hair loss and will affect up to 70% of men and 40% of women at some point in their lifetime. Men pattern baldness typically begin with hairline recession at the temples and continue with vertex balding, while women normally diffusely thin over the top of their scalps. Some other factors playing a role in this type of alopecia are genetics, environmental, health and even some life-style factors. Some clinical studies have found an association between early androgenic alopecia, insulin resistance and metabolic syndrome.
Androgenic hair loss in males follows usually a well known pattern (hence the name). Look at the photos: it begins above the temples and vertex, the hair line recedes gradually. In the later stages, a rim of hair at the sides and rear of the head remains – the ‘Hippocratic wreath’, and rarely progresses to complete baldness. The Hamilton-Norwood scale has been developed to grade androgenic alopecia in males.
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.