L-arginine is an essential amino acid that is produced in the human body from the amino acid L-citrulline. It is a direct precursor to nitric oxide, which helps dilate blood vessels, including those in the penis.

For a study in the Journal of Endocrinological Investigation, researchers looked at the effects of L-arginine supplementation on men with mild to moderate erectile dysfunction. Supplementation for three months significantly improved erectile dysfunction.

At the end of the study, 74 percent of patients with mild to moderate erectile dysfunction showed significant improvements.

It’s estimated that some 15 percent of men up to age 50 and nearly 50 percent of men ages 50 to 80 suffer from erectile dysfunction. Although drugs such as Viagra can treat erective dysfunction, L-arginine is a safe, effective, and inexpensive alternative.

I have found doses of 1,000 mg to 2,000 mg per day to be a safe and effective treatment for erectile dysfunction.