L-arginine is a type of amino acid that has several different functions within the human body. Typically, the body makes enough of it to function properly. However, people who have certain medical conditions may need to use L-arginine supplements if their body does not produce enough of this amino acid. Possible side effects include stomach pain, bloating, and diarrhea.
L-arginine is a semi-essential amino acid. This means that a dietary intake of L-arginine is not typically necessary, as the body can usually make the amino acid on its own. However, levels can be low in people who have certain medical conditions, and supplementation with L-arginine may be beneficial in some situations.
(Click L-Arginine Benefits for more information on what it is used for.)
L-arginine has several different functions within the cells of the human body, many of which are related to nitric oxide production. It is used in the body to make nitric oxide, an important substance that causes the blood vessels to relax. It may also have antioxidant properties. There is some research that suggests that it may inhibit angiotensin-converting enzymes (ACE), much like ACE inhibitor blood pressure medications. L-arginine may also stimulate the production of certain hormones, such as growth hormones, prolactin, and insulin.
These are just a few of the ways that researchers think it may work for a variety of conditions. As more studies are done, more information will become available about how it works.
Early research suggests that it may be effective for several uses. However, some uses are more valid than others (see Does L-Arginine Work? for more information).