Hormones are very effective and efficient biochemical messengers that are produced by the body’s various glands. Glands secret hormones directly into the blood to ensure the message is clearly received. Hormones are very powerful, meaning that only a very small amount of hormones can produce dramatic effects.
Testicles are glands and they secrete testosterone, the major male sex hormone, and the basis of the hormone that triggers hair loss. Only after the testicles develop during puberty do they produce enough testosterone to trigger hair loss in men. In addition to the testicles, the adrenal glands, located above each kidney in men and women, produce androgenic hormones.
We know that it is the testosterone derivative dihydrotestosterone (DHT) that causes androgenetic alopecia. DHT forms when testosterone comes into contact with the enzyme 5-alpha reductase. This enzyme is found only in areas near the prostate gland, testes, and adrenal glands and… You guessed it… In hair follicles. It is then DHT binds to genetically susceptible hair follicles, causing longer hair growth rest periods and hair shaft miniaturization, and baldness.
The hair loss medication finasteride (Propecia) works by binding to 5-alpha reductase molecules, preventing them from converting testosterone into DHT. The results are a decrease in the concentration of DHT, which will halt and sometimes even reverse the miniaturization process.