Why would propecia give you sexual side-effects? I have read up on DHT and have read up on erections and there seems to be no correlation. I know DHT is present in the testes but the main culpret for achieving an erection excluding psychological factors is nitric oxides is it not? Also during the study on propecia didn't the placebo group experience sexual side-effects. Did Merk tell people in both procedures that you may experience sexual side-effects? Basically if I was to take propecia I couldn't care less about having less desire for sex. Lol as far as I'm concerned that will probably be a good thing. I am not too bothered about fatigue either. The only effect which concerns me is the potential difficulty in achieving an erection. So please could someone clear this up for me. I would like a scientific answers please (chemistry kid) but anecdotal responses are welcome as well.