L-Arginine is an amino acid present in the proteins of all life forms. It is classified as a semiessential or conditionally essential amino acid. This means that under normal circumstances, the body can synthesize sufficient larginine to meet physiological demands; there are, however, conditions where the body cannot. lArginine is essential for young children and for those with certain rare genetic disorders in which synthesis of the amino acid is impaired. Some stress conditions that put an increased demand on the body for the synthesis of larginine include trauma (including surgical trauma), sepsis, and burns. Under these conditions, larginine becomes essential, and it is then very important to ensure adequate dietary intake of the amino acid to meet the increased physiological demands created by these situations. lArginine is found in many foods, including dairy products, meat, poultry, and fish. It plays a role in several important mechanisms in the body, including cell division, wound healing, removal of ammonia from the body, immunity to illness, and the secretion of many important hormones.
L-Arginine has been shown to promote natural growth hormone (GH) release from the pituitary gland. GH has been shown to support a healthy lifestyle and may minimize age-related decline. You can measure the GH enhancing effects of larginine by measuring your blood levels of somatomedin C (IGF1), a GH metabolite. lArginine has also been shown to support the immune system as well as to maintain a positive nitrogen balance and reduce protein catabolism. The effect of arginine on growth hormone levels has interested body builders. In a controlled trial, when arginine and ornithine (500 mg of each, twice per day, five times per week) were combined with weight training, a greater decrease in body fat was obtained after only five weeks than when the same exercise was combined with a placebo.
Arginine is also needed to increase protein synthesis, which can in turn increase cellular replication. Therefore, arginine may help people with inadequate numbers of certain cells. For example, some studies, though not all, have found that men with low sperm counts experienced an increase in the number of sperm when they supplemented with arginine. Arginine’s effect on increasing protein synthesis improves wound healing. This effect has been shown in both animals and people (at 17 g per day).
L-Arginine is required for the body to synthesize nitric oxide, which enables the arterial system to maintain its elasticity. Nitric oxide also helps to produce the endothelial relaxation factor, which is needed by the arterial system to expand and contract with each heartbeat. Nitric oxide is produced by all tissues of the body, and may support a healthy cardiovascular system. Based on this information, arginine has been used for various cardiovascular diseases, including congestive heart failure and intermittent claudication, as well as for impotence, female sexual dysfunction, and interstitial cystitis.
Arginine’s effect on immunity has created an interest in using it as part of an “immune cocktail” given to severely ill hospitalized patients and also for preventing colds. lOrnithine has been used as an alternative, since it metabolizes to larginine in the body.
Various doses of larginine are used. For cardiovascular health reasons, doses of 8–21 g daily have been used in divided doses. To help aid with sperm quantity and quality, doses of 10–20 g daily have been used in divided doses. Doses of 5 g daily have been used for erectile dysfunction. Doses of 1.5–2.4 g daily have been used for interstitial cystitis.