Male pattern baldness (MPB) is an ailment that affects the hair count of men in the UK and leads to mild or moderate hair loss. The cause of MPB is due to the miniaturization of the hair follicles, which is the reason hair recedes and drops from the head. Male pattern baldness is the most common cause of hair loss and will affect almost 70% of men at some point in their lives. The initial symptoms of MPB are hairline recession at the temples and front of the head. The causes of male pattern baldness, though, are not fully known and are presumed to be based on both genetic and environmental factors. However, there are two main treatments to slow or even reverse the effects of male pattern baldness. Two FDA approved drugs, Minoxidil (Rogaine) and Finasteride (Propecia).
Minoxidil is a topical treatment, while Finasteride is an oral pill. Propecia is the brand name version of Finasteride that is produced by Merck. Propecia is a type 2 5a-reductase inhibitor, which means that the drug inhibits the 5a-reductase enzyme in men. This enzyme is responsible for the conversion of testosterone to dihydrotestosterone. Initially Propecia (and similar chemical drugs), were not used to treat male pattern baldness, and were in fact used to treat benign prostate hyperplasia (more commonly known as enlarged prostate). Off-label uses of Propecia included male-to-female transsexual hormone replacement therapy because of its inhibiting effect on converting testosterone to dihydrotestosterone.
The use of Propecia for male pattern baldness was not discovered until some men (who were bald or balding) that were taking Propecia for enlarged prostate started to regrow hair. Clinical studies testing this hypothesis were completed and Propecia was shown to have a significant effect on reversing or stopping male pattern baldness. However, the exact mechanism as to why it works is murky because the exact causes of baldness are not known. More importantly, although Propecia may reverse hair loss and actually regrow hair, it is not a permanent solution. Once a patient stops taking Propecia any hair grown will inevitably be lost, and after 6-12 months of stopping Propecia the patient will begin balding. In other words, Propecia is a temporary solution to male pattern baldness.
Taking Propecia is not without its side effects. Serious complications from taking Propecia include an increased risk of prostate cancer, diminished libido, anxiety and depression (and other mood disorders), and male breast cancer. Professional athletes who are trying to beat doping control tests also take Propecia because its testosterone inhibitor enzyme can mask the use of steroids and other testosterone boosters.