Research studies.   L-Arginine is an amino acid found in many foods and used by the body to make a substance that relaxes the blood vessels. It has a number of suggeted uses, including enhanced sexual performance in both women and men. Two studies involving this supplement and sexual function are reported in the Natural Pharmacist Encyclopedia (click Herbs & Supplements A-Z, then L-Arginine). A double-blind trial with men with erectile dysfunction was supportive. A separate study with postmenopausal women who had difficulty with sexual arousal was also positive. The latter, however, also included the drug, yohimbine.

Target Symptoms and Dosage.    In this context, the primary targets would be enhanced libido for women and erectile function for men. A typical supplemental dosage of L-Arginine is 2 to 3 g per day.

Side Effects and Contraindications.   At the recommended dosage levels, L-Arginine appears to be both safe and free of side-effects. Often stimulating the body's production of a hormone that increases stomach acid, it may be contraindicated for person with ulcers or taking other medications that are difficult to digest. L-Arginine may also be contraindicated for persons with herpes (either cold sore or genital).

Summary.  Caution, as always, is always warranted in combining this supplement with prescribed medications. The prescribing physician should be made aware of all supplments being used to limit the risk of undesired interactions.