I got lucky and found some article about it, if anyone else interested..
Q. Propecia and Running
I am a 53-year-old male recreational runner (20 to 25 miles per week), I supplement my running with strength training. I would like to try Propecia, the new prescription treatment for male pattern baldness. I understand that this drug has some antiandrogenic effects, at least on hair follicles and the prostate gland. How selective are these effects? Would it have any negative effects on athletic performance? Would it inhibit muscle growth and development in a strength-training program?
Samuel Smith
Springfield, MO
A. You are right about Propecia (finasteride) being an androgen hormone inhibitor. Propecia is the same medication as Proscar, which is used for benign prostatic hypertrophy at the five-milligram strength. The mechanism of action of finasteride is to inhibit the steroid 5-alpha reductase, which is an intracellular enzyme that converts testosterone into the potent androgen 5-alpha dihydrotestosterone (DHT). This enzyme is a Type II isoenzyme and is found primarily in the prostate, seminal vesicles, epididymides and hair follicles as well as the liver, but not the muscle. What this means is that the activity of the finasteride is confined almost exclusively to the target organs and should not affect muscle mass or athletic performance. The anti-androgen action of this medication is confined almost entirely to the scalp and prostate.
Finasteride is generally well tolerated. Adverse reactions usually have been mild and transient. The two most common side effects at the higher dose of five milligrams daily are impotence (3.7%) and decreased libido (3.3%). These side effects have not been reported at the dose used for male pattern balding.
Finasteride will not help you run faster or promote muscle mass, but it also won't inhibit your progress in your training regimen.
David C. Tattan, D.0., C.M.D.
