Tadalafil
"I started having some problems maintaining an erection at age 56.  I'm in excellent health, take no meds, and stay in very good shape.  Getting the erection wasn't the problem, but it started to peter out :) after 5 or so minutes and eventually return with a lot of effort.  Well, that's NO fun. I actually have had excellent results cutting a 5mg tab in half, and taking every three days.  I've had results up to 4 days between doses.  This stuff is amazing.  I've had no aches as some have reported, and just a touch of nasal congestion, but since I have allergies, I'm always just a tiny bit stuffy anyway.  If I wasn't looking for it, I probably wouldn't notice the congestion.  Anyway, a true miracle."