Hair loss is genetic, driven by hormones and the scalp's response.
Proposed fixes like BPC-157, rosemary oil, and egg yolks won't help, unfortunately.
See what really causes hair loss and how to treat it safely.
Start with the genes.
Male pattern baldness is up to ~80% heritable (Yap 2018, 205,327 men). It is not one gene. The largest study found 624 independent genetic signals.
The strongest one is the androgen receptor, on the X chromosome from your mother (Pirastu 2017). The androgen receptor is the part of the cell that DHT binds to.
Cells from balding scalp carry more androgen receptors than cells from the non-balding parts of the same head (Hibberts 1998). The androgen receptor gene mostly decides one thing: how much your follicles respond to DHT.
Men born unable to make DHT have normal to high testosterone. Balding has never been reported in them (Imperato-McGinley 2002). Testosterone binds the androgen receptor about half as tightly as DHT, and comes off it about 5 times faster (Grino 1990).
DHT holds on to the receptor. Testosterone keeps letting go. Bald men do not have more testosterone. Their follicles are more sensitive to DHT.
That is lever one. Finasteride and dutasteride block the enzyme that turns testosterone into DHT, so less of the signal reaches the follicle.
DHT does not kill follicles. It shrinks them, a little each cycle, until the hair is too fine to see.
The follicle is smaller, not gone. It can still be regrown.
Finasteride and dutasteride work on the signal that reaches the first gene on that list. You only need to lower DHT in your scalp. That’s why we launched Precision Dutasteride and several combinations of 0.005% Finasteride.
But the androgen receptor is only one gene.
The most prominent genes found so far, ordered by p-value are (Pirastu 2017):
1. AR (androgen receptor): X chromosome, from your mother
2. PAX1: autosomal, both parents
3. TWIST1: autosomal, both parents
4. IRF4: autosomal, both parents
5. EBF1: autosomal, both parents
6. AUTS2: autosomal, both parents
7. TWIST2: autosomal, both parents
8. WNT3: autosomal, both parents
9. FGF5: autosomal, both parents
10. SETBP1: autosomal, both parents
Model all of it, the X-linked risk (mother only) plus half of the autosomal risk (shared), and split it by parent:
> About 56% of your genetic risk traces to your mother, and about 44% to your father.
> And the entire reason your mother edges ahead is one chromosome: the Xq12, carrying AR.
Hair loss is genetic, from both parents. Your hairline is close to a coin flip between which one, your mom or dad.
The genes that decide your hairline are part of the map we have to the next set of treatments, to turn a slick bald scalp fully hairy.