Dihydrotestosterone (DHT) is a byproduct of the hormone testosterone, which is formed in different areas such as the prostate gland and hair follicles. Hair follicles which are susceptible to genetic male patterned baldness contain DHT receptors. Over time as males produce more and more DHT the molecules affect hair follicles and cause them to become decrease in size, and eventually fall out permanently.
DHT and having the gene of male pattern baldness are the primary contributing factors for male pattern baldness. Women with female-pattern baldness, unlike men with male-pattern baldness, are usually not characterized by increased production rates of DHT due to their low levels of testosterone. However if for any reason a woman has increased testosterone, she may develop female patterned baldness just like a man does with the same mechanism.
Hair in the areas that are prone to male patterned baldness such as corners, top and crown areas are loaded with DHT receptors in men with Androgenetic Alopecia. However, the hair on donor areas such as back and sides do not have as much DHT receptors. This is why hair is more permanent on the sides and back as opposed to the top and front.
The distinction in hair quality on different areas (donor vs. recipient) allows a hair transplant surgeon to remove hair from one area and transplant it to the balding portions of the scalp. These transplanted hairs are permanent and won’t be affected by circulating DHT. Finasteride (Propecia) is a drug that blocks the conversion of testosterone to DHT by blocking the enzyme alpha reductase. DHT levels in hair loss patients decrease when they are on Propecia and this helps maintain healthy hair, and this helps some of the miniaturized hair become stronger.
We recommend medical treatment with DHT blockers in many of our patients who undergo a hair transplant procedure to help maintaining their own hair in addition to restoring the balding areas with hair restoration surgery.