5 alpha-reductase (also known as 5aR) is a special type of enzyme that helps the body perform a wide variety of important functions. 5a-reductase is necessary to create essential changes within the body’s natural chemistry, and acts as a catalyst to help define important characteristics such as gender. The general role of 5aR is the same in both men and women.
One of the most important functions of 5a-reductase is the way it metabolizes with other chemicals in the body, particular steroids. 5aR interacts with male sex hormones (usually testosterone) to create 5 alpha-dihydrotestosterone (DHT). DHT is much stronger than regular testosterone, and carries out a wide variety of crucial functions that regulate everything from brain health to sex drive.
As important as DHT is to our body’s wellbeing, and 5aR by extension, some people also have a genetic sensitivity to DHT that can cause baldness. For these people, DHT becomes counterproductive to hair growth because it gathers in the scalp tissue and shrinks the hair follicles, in men especially. When the hair follicles shrink enough, important proteins, minerals and vitamins can no longer reach the hair, the hair cannot go through its three growth stages, and thinning or loss occurs.
DHT is also what regulates gene expression, which signifies when dormant genes should become active and reveal themselves. This is why, if your hair has a genetic sensitivity to DHT, it can take a long period of time for this latent characteristic to go into effect.
In this regard, 5aR, being a precursor for producing DHT, can also be thought of as a precursor for baldness. Therefore, if the amount of 5a-reductase can be successfully controlled through medication, then the production of DHT can be regulated as a method to control balding.
Women have testosterone and other androgens (male sex hormones) in their bodies, albeit in much lower amounts than males. As such, they typically can produce DHT using 5aR with absolutely no hair loss. Some women’s hair follicles, however, are extremely sensitive to androgen-based DHT, and even a small concentration of DHT in the scalp is enough to make their hair follicles shrink as a result. As with men, this genetic trait can lay dormant for a long time before being activated by DHT.
5a-reductase also delivers vital nutrients such as vitamins, healthy fats, and cholesterol by allowing them to dissolve into the liver for processing. It also acts as a catalyst for bile acid synthesis, a process in which excess cholesterol is excreted by the liver.
There are three different types of 5 a-reductase deficiencies, each with their distinctive associated characteristics. The first type causes a lack of muscle and bone mass. The second type causes a rare birth defect where little to no 5aR enzyme results in males being born with genitalia deformations that appear effeminate. Sufferers of this deficiency actually switch sex to males during puberty, when a surge of testosterone causes a medical metamorphosis. The third type is a metabolic problem that does not allow 5aR to properly convert sex steroids, resulting in severe hormonal balances.