Update March 10, 2017
Hands up all those who’ve assumed over the years that Donald Trump is not simply the victim of a bad hairdo but does in fact wear a toupee. I’m betting that’s most of you! As it turns out, we’re all wrong because, according to Trump’s doctor, the infamous postiche look-alike hairstyle is indeed just a case of life imitating a hairpiece. His hair really is his own! Apparently grown with the help of a drug called finasteride and clearly styled to keep his detractors believing in the wig theory.
So what is finasteride? Being keenly interested in all things supplement related, we made it our mission to find out just what this wonder hair growth drug is, and does.
First and foremost, finasteride is a drug that inhibits the actions of an enzyme called 5α-reductase. 5α-reductase is responsible for converting testosterone to dihydrotestosterone, or DHT, in certain types of body tissues. Notably the skin, hair follicles, liver, brain, prostate gland, epididymides and seminal vesicles.
DHT and testosterone are both agonists. Their job is to bind with specific receptor molecules in cell membranes to initiate a particular physiological response within the cell. As DHT and testosterone are androgen (male sex characteristic) agonists the cellular responses they trigger are the development and maintenance of male traits and characteristics.
DHT itself is pivotal in the foetal development of external male genitalia. In adult males, it controls cellular activities in the seminal vesicles, prostate gland, skin and hair follicles. It’s also a more powerful agonist than testosterone.
The effects and side effects of DHT abnormalities were first formally noted in a small group of pseudohermaphrodite children in the Caribbean. These children were born without fully formed male genitalia and were raised as females up until puberty, when their testosterone kicked in and they began developing male characteristics, including male genitalia. The researchers discovered that the children all had a common genetic mutation that caused them to have low levels of 5α-reductase. They also had correspondingly low levels of DHT and that was found to have been responsible for the abnormal foetal development of their male genitalia.
Researchers also noted that as these individuals matured, even though they developed male genitalia and some other male characteristics, they still had underdeveloped prostates. It was further documented that they had no incidences of benign prostatic hyperplasia (BPH), prostate cancer, or male pattern baldness. They also had less body hair.
A researcher at Merck read the final presentation notes and became interested in the apparent link between low levels of DHT and small prostates. He figured that if he could develop a drug that blocked the actions of 5α-reductase and lowered DHT levels, it could conceivably be an effective treatment for men suffering from BPH. He was right! The result was the development of a drug called finasteride, marketed by Merck as Proscar. Finasteride was subsequently also approved for use in the treatment of male pattern baldness and marketed as Propecia.
How does DHT affect hair growth?
There are many reasons why men lose hair but androgenic alopecia, also known as male pattern baldness or MPB, is the main one. MPB is a genetic condition that makes some hair follicles sensitive to DHT.
As we mentioned earlier, skin and hair follicle cells are part of the specialised group of cells in which DHT is produced. Oil glands in hair follicles store the 5α-reductase enzyme that produces DHT from testosterone. Amongst other things, DHT is responsible for signalling the skin and hair follicle cells to produce the heavier, coarser and denser hair growth that is a typical male characteristic.
But in someone who has inherited genetically DHT sensitive hair follicles, DHT causes those hair follicles to shrink over time so they produce progressively less viable hairs until eventually the follicle itself dies. However, when the level of DHT in the hair follicles is reduced undamaged hair follicles continue to function normally, particularly if treatment is started early enough. For men who have already started losing hair, finasteride slows down their hair loss and in some cases they may even start to grow their hair back. However, if treatment is discontinued, hair loss resumes as DHT levels increase again.
Whilst finasteride has not been effective in treating pattern hair loss in women, it has successfully been used to treat excessive body and facial hair growth, a condition called hirsutism.
And as for side effects…. During the first year of treatment with finasteride there is a greater risk of erectile dysfunction, impotence, ejaculation disorder and decreased libido. However, in most cases this subsides over time. Probably the biggest concern with finasteride is the fact that it also lowers levels of prostate-specific antigen (PSA), which may mask prostate cancer. Under normal circumstances, a significant rise in PSA levels is considered a marker for prostate cancer. But when PSA levels are being kept artificially low by finasteride, a prostate cancer screening PSA test, which measure blood levels of PSA, will obviously still register low to normal PSA levels even if prostate cancer is present.