Male hair loss is a pretty common problem. (Did you just touch your head?) By age 35, two-thirds of American men will experience some degree of hair loss, according to the American Hair Loss Association. By age 50, up to 85 percent of men will have significantly thinning hair. For more than 95 percent of men, androgenetic alopecia, or common male pattern baldness, is the leading cause of this problem.

Thankfully, drugs such as minoxidil (Rogaine) and finasteride (Propecia) are available to help mitigate the dwindling follicles. But did you know finasteride can affect prostate cancer screening tests? That's an important detail to know if you are taking drugs for hair loss.

What is finasteride?

Dihydrotestosterone (DHT) is an androgen, a sex hormone involved in the development of male sex characteristics. However, high levels of DHT can also shrink the hair follicle and lead to baldness.

Finasteride, which is approved by the Food and Drug Administration (FDA), is a first-line drug for male pattern baldness that effectively lowers DHT levels in the scalp by as much as 60 percent when taken daily. It