I have tried most all the supplements ever mentioned on this forum from time to time with little if any positive results. I have diabetes induced ED; however, I have found an otc supplement, Maxidus, which provide me with an 8 EQ erection if I take one pill 3 hours in advance and one pill 30 minutes prior. I can bring it up to a 9+ if I add constriction. It provides similar results as when I use 50 mg of Viagra. On the down side, it is not taken daily so it does not offer erections on demand, but rather requires some advance planning. I have been using it for over two years with about a 90% success rate. Because of my ED, I am unable to get and/or maintain an erection without assistance (Viagra, pumping, constriction, etc) so my case may be different from most guys, but I use it successfully two or three times a week.