Androgenetic alopecia
From Wigipedia, the free hair encyclopedia
Androgenetic alopecia — pattern baldness — is the most common form of hair loss, eventually affecting up to roughly half of all men and women.1 It is the baldness behind the whole war against baldness: the comb-over, the toupée, and the modern hair-loss drug aisle.
How it works
The “androgenetic” name packs in both causes: androgens (male sex hormones) and genetics. In affected scalps, follicles are unusually sensitive to dihydrotestosterone (DHT), a potent androgen made from testosterone by an enzyme called 5-alpha-reductase. Over years, DHT drives a process called miniaturisation: each growth cycle produces a slightly finer, shorter, lighter hair, until the follicle yields only near-invisible “peach fuzz” — or nothing.1
Crucially, the follicles are shrinking, not dying outright, which is why treatments that shift the balance can coax some of them back.
The pattern
The reason it is called pattern baldness is that it follows predictable maps. In men, loss usually starts at the temples and the crown (the vertex). In women, the frontal hairline is typically spared while the hair thins diffusely over the top of the head, often first noticed as a widening center part.1
What helps
Two drugs dominate. Minoxidil prolongs the growth phase of the follicle, and finasteride blocks the enzyme that makes DHT. Both can slow loss and partly regrow hair, but both work only while you keep taking them — stop, and the original trajectory resumes.
See also
- Alopecia and alopecia areata
- Minoxidil and finasteride
- The comb-over