Unless they have own experience in the field, a large number of men would not believe that food could be a major influence on sexual function. But as a matter of fact, food will exert a stronger influence than many of the substances sold as sexuality-enhancing supplements. Take for example nuts. Vitamin E is an, albeit weak, vasodilator. Arginine is an amino acid that is used by the body to form nitric oxide.
Nitric oxide works as the primary neurotransmitter facilitating erections.
Theoretically, pure l-arginine, taken as nutritional supplement, should facilitate the erectile response. However, this doesn't seem to work as it should. I have experimented myself with various dosages of arginine, probably with up to ten grams a day. My own experience is that at best, arginine supplementation is ineffective. A worse possible scenario is that supplementation with pure arginine is counterproductive.