Is Hair Restoration Worth the Risk of Potential Persistent Sexual Side Effects?

Hair loss, whether it’s partial or complete, is troubling to many people. By age 50, 35 to 50 percent of American men have significant hair loss, and hair thinning and loss increases with age. Many people associate hair loss with premature aging, making pharmaceuticals that arrest hair loss quite popular.

Recent findings indicate that the 5α-reductase inhibitors (available since the late 1990s, with finasteride the most effective and most commonly used product for male pattern balding) may produce persistent adverse effects. Michael Irwig from The George Washington University in Washington, DC, recently published a paper that assembled current findings on this topic in Current Opinion in Endocrinology, Diabetes and Obesity.

Reports of persistent sexual and nonsexual side effects emanate from the Food and Drug Administration’s analysis of post-marketing surveillance. They indicate that these side effects—erectile dysfunction, low libido and orgasm difficulties—are uncommon, and most likely to occur in younger men who have taken finasteride 1 mg for androgenic alopecia. Former finasteride users who experience these effects also have higher rates of depressive symptoms and suicidal thoughts compared to untreated men with androgenic alopecia.

Causative mechanisms for sexual side effects in humans are unknown at this time, but one study found that men who had taken finasteride had low cerebrospinal fluid concentrations of dihydrotestosterone, progesterone, dihydroprogesterone and allopregnanolone. Their CNS levels of testosterone and other steroid precursors were also depressed.

Irwig noted that one randomized controlled study found that healthy men age 18—55 years who took finasteride 5 mg daily experienced reductions in sperm count, semen volume, sperm concentration, and sperm motility. For roughly 5% of study participants, the decline in sperm count was greater than 90%. Most sperm counts recovered after medication cessation.

Animal studies also show hormone aberrations. Finasteride-treated rats experience changes in the anatomical structure and composition of the penis, with more collagen deposition and less smooth muscle.

In addition, many men report reduced decreased alcohol tolerance while taking finasteride. Many men spontaneously decrease their alcohol consumption or abstain altogether.

Irwig indicated a subset of men is genetically more susceptible to adverse effects from 5α-reductase inhibitors; polymorphisms in the coding region of the 5α-reductase type 2 gene appear related to sperm alterations. He urged prescribers to counsel patients seeking treatment for androgenic alopecia that the full safety profile for these drugs is still incomplete, and warn them about potential risks.