Androgenic hair loss
There are many conditions where hair loss is the primary symptom. Still, the number one cause of hair loss for men and women is androgenic genetic alopecia, with DHT playing a primary role.
What is DHT?
DHT (dihydrotestosterone) is a hormone belonging to a class known as androgens. Androgens function to regulate the development and maintenance of masculine characteristics. They are involved in growth, body development, and reproductive health.
Androgens are typically thought of as male hormones, but women also produce them in smaller amounts. Androgens are produced by the testicles in men, ovaries in women, and the adrenal glands of both sexes. These hormones influence muscle development, fat production, bone density, changes during puberty, as well as sexual desire and function.
DHT is derived from the conversion of testosterone by the action of the 5-alpha reductase enzymes. It is the most potent of the androgens and is considered pure androgen in that it cannot be converted to estrogen.
What does DHT do?
Although DHT has been given a bad reputation due to its role in male-patterned hair loss, it is an essential hormone from fetal development until puberty, after which it becomes implicated in certain medical conditions in males.
During fetal development, DHT plays an essential role in sexual differentiation in male fetuses because it promotes the development of male external genitalia. So, without the influence of DHT, the fetus would appear female.
During puberty, it is involved in the growth and maturation of the penis and scrotum, the deepening of the voice, and increasing muscle mass. It is the primary androgen responsible for facial hair, body hair, and prostate growth.
However, DHT has no significant role in normal male physiology during adulthood and is most notably implicated in prostatic enlargement and MPHL.
How does DHT cause hair loss?
DHT is formed primarily in the body’s peripheral tissues, where it exerts its effects. And for male pattern hair loss, this conversion occurs at the hair follicle.
Testosterone is converted to DHT at the hair follicle when it comes in contact with the 5-alpha reductase enzymes. DHT then binds to receptors on susceptible hair follicles, activating genes that start the cascade of reactions that lead to progressively shorter growth cycles causing the hairs to become shorter and thinner to a point where the follicle is incapable of sustaining healthy hair growth.
Men with male pattern hair loss have higher 5-alpha reductase enzyme levels and androgen receptor activity at the hair follicles of the balding scalp region, which leads to higher local DHT levels.
Genetics determines if the hair follicles will have DHT receptors, and the process of male pattern hair loss can take several months and even years. DHT only attacks scalp hair follicles that have DHT receptors. Hair follicles that do not have DHT receptors are unaffected.
What are the treatments for patterned hair loss?
There are two FDA-approved medications to treat androgenic alopecia: finasteride and minoxidil. These treatments are optimal for when hair loss is first beginning. Individuals will have varying responses to either of these treatments. It should be noted that neither of these treatments “regrow hair” or stop the hair loss process. Both of these medications require consistent daily use to be effective, and once the medicines are stopped, any benefit gained would eventually be lost. They work to “pump the brakes” to slow down the hair loss process and allow users to keep the hair they currently have for longer, but genetics eventually wins this tug of war.
Thankfully, there is a permanent solution to hair loss caused by DHT: surgical hair restoration. During this treatment, hairs that do not have DHT receptors and are therefore blind to the effects of DHT are moved to the balding areas. These hairs maintain their resistance to DHT even when transferred to regions of blading and will grow indefinitely.