L-Arginine

Injury significantly increases the need for the amino acid arginine, which is essential for a variety of metabolic functions.  In a clinical study published in a major medical journal, arginine supplementation significantly increased the amount of reparative collagen synthesized at the site of a "standard wound" (an incision 5cm long and 1mm in diameter) made in healthy volunteers.  The same study found marked enhancement of the activity and efficacy of peripheral T-lymphocytes (white blood cells in the bloodstream) [Kirk et al. 1993].

Other animal and human studies have demonstrated that arginine stimulates the cell-mediated immune response and protects against bacterial challenges [Gurbuz et al. 1998].  Arginine's ability to improve wound healing and immune-system function is thought to be related to its stimulation of the release of growth hormone.  Growth hormone plays a critical role in modulating the immune system and is essential for muscle growth and development.  That growth hormone secretion diminishes progressively with advancing age is one of the primary reasons for the decline in immune-system function and muscular strength as we grow older.

Under normal conditions, the 5gm per day of arginine found in the typical Western diet would be marginally sufficient to maintain tissue health.  Research has demonstrated, however, that in patients undergoing gallbladder surgery, supplementing 15gm of arginine for 3 days prior to surgery significantly reduced nitrogen excretion (evidence that the patients were using, not excreting, amino acids in order to heal) when compared with patients receiving conventional nutritional support.  In patients undergoing surgery for gastrointestinal cancer, supplementation with 25gm of arginine a day for 7 days improved their nitrogen balance as measured 5-7 days after surgery and led to more rapid recovery and discharge from the hospital. [Daly et al. 1995]

Intravenous injections of the amino acid arginine have been shown to be remarkably effective at improving intermittent claudication.  In a double-blind trial, 8gm of arginine, injected twice daily for three weeks, improved pain-free walking distance by 230% and absolute walking distance by 155%, compared to no improvement with placebo. [Boger RH, Bode-Boger SM, Thiele W, et al. Restoring vascular nitric oxide formation by L-arginine improves the symptoms of intermittent claudication in patients with peripheral arterial occlusive disease. J Am Coll Cardiol 1998;32: pp.1336-44]

Oral administration of L-arginine (700mg qid during continuous transdermal nitroglycerin therapy) increased treadmill walking time until the onset of moderate angina in a small well-controlled trial. [J Am Coll Cardiol 2002;39(7): pp.1199-203]

Arginine promotes viral replication of herpes.  In some people, changing the dietary ratio of lysine to arginine reduces the frequency and intensity of outbreaks.

A comprehensive list of foods and their lysine/arginine content can be found here.

L-Arginine is the primary source of nitrous oxide (NO), an odorless gas made of nitrogen and oxygen that relaxes muscles and increases blood flow to organs – including the heart and penis.  By facilitating blood flow through the erectile tissue of the penis, NO produced from L-arginine can give men erections that are bigger, harder and more frequent.

In a group of 15 men with erectile dysfunction given 2,800mg of arginine per day for two weeks, six were helped, though none improved while taking placebo.  Although little is known about how effective arginine will be for men with erectile dysfunction or which subset of these men would be helped, available research looks promising and suggests that at least some men are likely to benefit. [Int J Impot Res 6: pp.33-6, 1994]

The dose can range from 1 to 3gm with meals, or up to 15gm about 45 minutes before sexual activity.  Arginine is not recommended if you have diabetes, arthritis, cancer, shingles, herpes I (fever blisters, cold sores) or herpes II.

Arginine promotes viral replication of herpes.  In some people, changing the dietary ratio of lysine to arginine reduces the frequency and intensity of outbreaks.  Foods that are lower in lysine and higher in arginine such as chocolate, peanuts and other nuts, grains, peas, seeds, oatmeal and whole-wheat products should be reduced or eliminated from the diet.  Lists of foods and their lysine-to-arginine content are available on the Internet.

A comprehensive list of foods and their lysine/arginine content can be found here.

Clinical studies have shown improved immune function in cancer patients fed arginine.

Arginine, 3gm per day in divided doses on an ongoing basis, can reduce symptoms.  In some people with herpes, the arginine may need to be offset with lysine.  The body also uses arginine to make nitric oxide, which helps to relax smooth muscles like those found in blood vessels and the bladder.  Based on this known mechanism, arginine has been proposed as a treatment for various conditions that may be caused by limited blood flow.  Some researchers theorize that arginine's effects on nitric oxide synthesis might help relax the bladder, making it a useful treatment for IC.