I've had disasterous erection problems since young 20's (almost 20 years ago now). After much testing the diagnosis was 30%+ reduced blood flow (for no known or particular reason) to the penis area. After 20 years of working on this the best combo I've come up with is Nitrix or any type of NO supplement I guess, PT-141 2mg, and Tadalafil 90mg every day. Adjust dosage accordingly, but for my weight plus best results/minimal sides that is the ratio. Still takes my girl and I a bit of action to get it up, but once it is, I'm hard as a rock and can last forever. FYI - the PT141 is an injectable, however not immediate results. Takes a couple hours to get kicking if not taking daily.