L-arginine, or arginine, is an nutrition enhancer that triggers your body to manufacture protein. Your body usually makes ample supplies of L-arginine, but supplements are sometimes used to treat medical conditions. Dietary sources of L-arginine include meat, fish and dairy products. Because L-arginine functions as a chemical precursor to a blood vessel-widening agent, it is used to treat chest pain, atherosclerosis, heart failure, erectile dysfunction and vascular headaches, says MayoClinic.com. Some individuals take L-arginine to improve kidney function following a transplant, to enhance the immune system and boost athletic performance. L-arginine is combined with over-the-counter and prescription medications to treat a variety of health conditions.

Your body converts L-arginine into nitric oxide which allows blood vessels to dilate for improved blood flow. Drugs.com indicates that excessive concentrations of nitric oxide are toxic to brain tissue. Although there is no current recommended daily intake for L-arginine, the maximum dose considered to be safe is 400 to 6,000 mg daily. Do not take L-arginine if you have recently suffered a heart attack. L-arginine may increase the risk of death following a heart attack, and this risk increases for older individuals. Women with high-risk pregnancies should avoid L-arginine.

L-arginine is generally well-tolerated, some of the reported side effects that you may experience from L-arginine are bloating, diarrhea, hives, leg restlessness, lower back pain and endocrine changes. L- arginine may increase the danger of bleeding and may produce changes in blood sugar levels. Use L-arginine with caution if you have a bleeding disorder, diabetes or hypoglycemia.

L-arginine should not be taken without your doctors knowledge and supervision. Inform your doctor of all current medications and supplements taken, as well as allergic reactions you may have experienced to any medication. The supplement status of L-arginine means its strength, purity and safety are not guaranteed by the U.S. Food and Drug Administration.