Arginine

Arginine is an amino acid (one of the building blocks of protein) used by the cells to make nitric oxide, which is important for cardiovascular health. Nitric oxide released by the inner layer of cells (endothelium) in the arteries relaxes those vessels, keeps them flexible, and boosts blood flow. Among arginine supplements, the best known was the HeartBar, a soy-based candy bar containing arginine and other ingredients. It used to be marketed with claims that it could reduce the risk of heart disease and even eliminate the need for surgery and medication among patients with heart disease. However, the Federal Trade Commission stopped the company from making such unsubstantiated medical claims. Other types of arginine supplements include Herc Vitality Drink Mix and Niteworks, whose claims are also exaggerated.

Claims, purported benefits: Prevents or treats heart disease and circulatory diseases, combats fatigue, stimulates the immune system, treats impotence, fights cancer, etc. Many studies have found that arginine supplements can boost nitric oxide production. Some have also suggested that the supplements can improve the function of blood vessels, enhance coronary blood flow, lower blood pressure, and even reduce angina or other symptoms in people with heart disease and/or vascular disease.

Bottom line: Don’t take arginine without talking to your doctor about it. If you have cardiovascular problems, you should be under medical supervision. There are proven drugs that can help. Cardio-protective drugs such as statins and ACE inhibitors increase nitric oxide availability. If you have erectile problems, talk to your doctor. Your problem may not be nitric oxide. Arginine can have serious side effects, especially when taken with certain other drugs. Long-term safety of arginine supplements is unknown. Increased nitric oxide might be dangerous for people with certain medical conditions, such as kidney failure or cancer. And no one knows what’s the right dose or when it should be taken.