What is Arginine?

The amino acid Arginine (l-Arginine HCl) is acquiring a reputation for keeping the body’s biggest muscle, the heart, in tip-top shape. In addition to the heart, Arginine can also needed to increase protein synthesis which can in turn increase cels. Studies have found that men with low sperm counts experienced an increase in the number of sperm when they were supplemented with Arginine.

How does it work?

Arginine supplements appear to reduce mildly elevated blood pressure by enhancing the synthesis of Nitric Oxide (a gas) in the cells lining the blood vessels.  This helps dilate vessel walls and improves blood flow around the heart.  In fact, Nitric Oxide ranks as the body’s most potent blood vessel expander.  In addition, Arginine may help in treating male fertility caused by circulation problems.

Where does it come from?

Arginine is an amino acid found in many foods, including dairy products, meat, poultry, fish, nuts and chocolate.

Safety / Side Effects

Arginine has so far appeared to be free of obvious side effects.

Studies Involving Sperm

The clinical efficacy of l-Arginine HCl was tested in 40 infertile men. (Minerva Urol Defrol. 1994 Dec; 46(4): 251-3).  All of these men had a normal number of spermatozoa (720 million/ml), but a decreased motility.  This decreased motility was not due to infection or to immunological disorders.  The treatment consisted of 80ml of 109 l-Arginine HCl administered daily for six months. l-Arginine HCl was shown to improve the motility of spermatozoa without any side effects.


Certain medicines may interact with Arginine.  Consult with your physician or pharmacist to determine if any of your medications might interact with this supplement.


Scibona M, Meschini P, Capparelli S, et al. Larginine and male infertility. Minerva Urol Nefrol 1994;46:251-253.