The excellent reference work Natural Products: A Case-Based Approach for Healthcare Professionals, Karen Shapiro, ed., published by the American Pharmacists’ Association in 2006, provides background and references to the scientific literature on the use of L-arginine for erectile dysfunction.
L-arginine, an amino acid required for the synthesis of nitric oxide, has been studied for erectile dysfunction with a dosage of 5g (= 5 x 1000mg) per day. It was also a component in a study of women with decreased libido; dosage in that study was 2.5g (= 2.5 x 1000mg) per day. L-arginine was found to be “well-tolerated” in general, though it has hypotensive (or blood pressure-lowering) effects and should not be used following heart attack.
Citation: “Erectile Dysfunction,” pp. 51-62, in Natural Products: A Case-Based Approach for Healthcare Professionals, Karen Shapiro, ed., (Washington, DC: American Pharmacists’ Association, 2006).