The male hormones involved in the mechanism of androgenetic hair loss are called androgens. The answer to the question “How do androgens cause baldness?” will need explaining in more than the space of a few lines.
There are a number of reasons behind the cause:
- Androgens act by interacting with specific receptors found on cell membranes or inside cells, as all other hormones do.
- Several forms of the androgen hormone can affect the hair follicles and different areas of the skin respond to the same androgen in various ways.
- For example, hairs located on the armpit respond to androgens by growing, whereas hairs in the scalp fall out in response to them.
The two types of androgens involved in male pattern hair loss are testosterone and dihydrotestosterone (DHT hormone).
- The enzyme- 5-alpha reductase turns inactive testosterone into a more power form which is called dihydrotestosterone.
- 5-alpha reductase is the key enzyme involved in androgenetic hair loss.
- Once dihydrotestosterone is formed it has the ability to overpower any androgen molecule present on a hair follicle, leading to hair loss.
- Plain testosterone can also act on the follicles, but its effect of causing hair loss is weaker.
THE IMPACT OF TESTOSTERONE AND DIHYDROTESTOTERONE
The combination of testosterone and dihydrotestoterone, result in enduring changes to hairs covering the scalp and ends with hair loss.
- The power of these two hormones grouped together break down the hair growth cycle by making the anagen (growth) phase progressively shorter.
- The catagen (intermediate) and telogen (shedding or resting) phases remain the same resulting in an increased number of resting hair follicles within the hair growth process.
- The more hairs that enter the resting phase increase the number of shedding hairs.
- The shedding process starts with a decrease in length and fullness. Hairs grow thinner and shorter leading to brittle hairs that are prone to fall out.
You may wonder why some males develop male pattern baldness and others do not. All men and women have the hormones that cause hair loss within their bodies so you would think that everyone would develop baldness.
There isn’t a straight answer as to why some of us develop baldness over others, however there are speculations listed below:
- The number of androgen receptors in a single hair follicle is higher in patients that have androgenetic hair loss compared with those that do not.
- Balding persons’ hair follicles have a higher sensitivity to androgens than normal, which results in a more pronounced effect of hair loss.
- The enzyme 5-alpha reductase is higher in the balding area, which converts more testosterone to dihydrotestosterone. The higher the proportion of the DHT hormone to testosterone, the faster the hair loss process.