Androgenetic alopecia is the most common form of hair loss in men (may occur in women too), and is also called male pattern baldness, male pattern alopecia, androgen-dependent alopecia or balding. It happens through gradual regression of the frontal hairline and thinning on the vertex, and eventually hair remains only around the back and sides of the head. The culture of the industrialised nations is youth-orientated, so balding often causes psychological distress and may reduce the quality of life.
What changes happen during male pattern baldness? While terminal hair follicles of a young adult produce long, thick, pigmented hairs, balding person’s follicles are smaller and form short, colourless, virtually invisible vellus hairs. These miniaturisation processes occur over many years with hair follicles reducing in size and depth in the skin. Each follicle grows hair in cycles of three phases: the growth phase is anagen, the regression phase is catagen and the resting phase is telogen. While androgenetic alopecia develops, anagen shortens, and the proportion of telogen hairs increases.
What is essential for the development of androgenetic alopecia? Let’s see what is in “The Shiny Bald Head Kit”:
- Androgens. They pass through the plasma membrane and bind to specific androgen receptors, enabling them to bind to specific hormone-responsive elements in the DNA. This results in the initiation of translation of specific androgen-regulated genes and synthesis of their proteins. The main circulating androgen in men – testosterone – is often metabolised intracellularly to the more potent androgen 5α-dihydrotestosterone (by the enzyme 5α-reductase). Androgen receptors can be activated by both testosterone and 5α-dihydrotestosterone. It is interesting to note that men without functional androgen receptors do not develop androgenetic alopecia!
- Genetic predisposition. A strong correlation in incidence of male pattern baldness was found in more than 50 sets of sons and fathers, with around 82% of balding sons having balding fathers. The genetic involvement in androgenetic alopecia is still not fully clear, but I should probably mention the EDA2R gene on the X-chromosome and a locus on chromosome 20, as they are usually associated with male pattern baldness.
The aforementioned factors are must-haves for the development of male pattern baldness, but other notable agents can also supplement the “kit”.
Soon I will tell you about the available remedies for androgenetic alopecia and their limited success.