How Does DHT Promote Hair Loss?

• Age and DHT
• Gender Differences
• Scalp Region and DHT

DHT binds to the androgen hormone receptors in the dermal papilla cells at the base of hair follicles. Its binding strength is five times that of testosterone and triggers certain genes that promote hair loss. Studies indicate DHT is also three to seven times more potent than testosterone.^{(16, 77, 81)}

One of the effects of DHT is miniaturization of hair follicles. Normal scalp hair follicles are the large terminal type, but in men and women with androgenetic hair loss scalp follicles shrink, the growth phase of the hair cycle is shortened, and the replacement hairs become fine and shorter.⁽¹⁶⁾

The increased transformation of testosterone to DHT by the enzyme 5α-reductase at the base of scalp follicles is variable. Some of the factors that influence DHT metabolism include the area of the scalp, gender, and age of onset.⁽¹⁶⁾

The DHT Effect in Hair Loss

Both men and women produce the androgen testosterone, a steroidal sex hormone. In men, testosterone is primarily produced by the testis, and in women mostly from the ovaries. Some testosterone is synthesized from androgens secreted by the adrenal glands. DHT is a metabolite of testosterone that behaves similarly, except with far greater potency.^{(77, 82, 83)}

How Does Age Affect DHT Hormone Levels?

In both men and women, AGA hair loss at a young age is linked to substantial amounts of follicular DHT.⁽¹⁶⁾

Do Men and Women Have Different DHT Hormone Levels?

Women with AGA may be less susceptible to DHT because of higher levels of aromatase enzymes overall, and specifically in the frontal region of the scalp. Aromatase enzymes transform testosterone into estrogen, leaving less of testosterone free to metabolize into DHT. In addition, gender-based differences in estrogen and testosterone/DHT receptors on hair follicles may also modulate the effect of DHT.^(16, 30)

Do Different Areas of the Scalp Have Different DHT Levels?

Different areas of the scalp are less responsive to the transformation of testosterone to DHT. In both men and women with AGA, typically the hair follicles in the occipital scalp region is androgen-insensitive and less likely to become miniaturized:⁽¹⁶⁾