Dihydrotestosterone (DHT, 5α-dihydrotestosterone, 5α-DHT, androstanolone or stanolone) is an endogenous androgen sex steroid and hormone.
The enzyme 5α-reductase catalyzes the formation of DHT from testosterone in certain tissues including the prostate gland, seminal vesicles, epididymides, skin, hair follicles, liver, and brain.
This enzyme mediates reduction of the C4-5 double bond of testosterone. Relative to testosterone, DHT is considerably more potent as an agonist of the androgen receptor (AR).
DHT has many roles. Apart from hair production, it is linked to benign prostatic hyperplasia, or enlarged prostate, and prostate cancer too.
DHT is a sex steroid, meaning it is produced in the gonads. It is also an androgen hormone.
Androgens are responsible for the biological characteristics of males, including a deeper voice, body hair, and increased muscle mass. During fetal development, DHT plays a vital role in the development of the penis and prostate gland.
DHT is more powerful than testosterone. It attaches to the same sites as testosterone, but more easily. Once there, it remains bound for longer.
Male pattern hair loss is the most common type of hair loss in men. Hair at the temples and on the crown slowly thin and eventually disappear.
The exact reason why this happens is unknown, but genetic, hormonal, and environmental factors are all thought to play a role. DHT is believed to be a major factor.
Male pattern hair loss, or androgenetic alopecia, is the most common type of hair loss among males.
Hormonal factors appear to play a role, and especially a male sex hormone known as dihydrotestosterone (DHT).
DHT has also been linked to hair loss in women.
Fast facts on dihydrotestosterone
- DHT is an androgen and helps give males their male characteristics.
- DHT is thought to cause hair follicles to miniaturize, and this contributes to male pattern hair loss.
- By the age of 50 years, over half of the men in the U.S. will probably experience hair loss mediated by DHT.
- Treatments that block DHT may help prevent hair loss.
Three phases of hair growth
To understand male pattern hair loss, we need to understand hair growth.
Hair growth is split into three phases: anagen, catagen, and telogen:
Anagen is the growth phase. Hairs remain in this phase for 2 to 6 years. The longer it lasts, the longer the hair grows. Normally, around 80 to 85 percent percent of the hairs on the head are in this phase.
Catagen lasts only 2 weeks. It allows the hair follicle to renew itself.
Telogen is the resting phase. The follicle lies dormant for 1 to 4 months. Normally between 12 and 20 percent of hairs are in this phase.
After this, anagen begins again. The existing hair is pushed out of the pore by the new growth and naturally sheds.
Male pattern hair loss happens when the follicles slowly become miniaturized, the anagen phase is reduced, and the telogen phase becomes longer.
The shortened growing phase means the hair cannot grow as long as before.
Over time, the anagen phase becomes so short that the new hairs do not even peek through the surface of the skin. Telogen hair growth is less well-anchored to the scalp, making it easier to fall out.
As the follicles become smaller, the shaft of the hair becomes thinner with each cycle of growth. Eventually, hairs are reduced to vellus hairs, the type of soft, light hairs that cover an infant and mostly disappear during puberty in response to androgens.
Users of anabolic steroid drugs, including bodybuilders, have higher levels of DHT. However, they often experience hair loss.
There are plenty of medications for DHT-related hair loss, and many of them have been proven to workTrusted Source by specifically targeting DHT production and receptor binding. There are two main types:
- Blockers. These prevent DHT from binding to 5-AR receptors, including those in your hair follicles that can allow DHT to shrink follicles
- Inhibitors. These reduce your body’s production of DHT.
But talk to a doctor first, as not all treatments may be safe or effective for you.