What is L-Arginine?

L-Arginine is one of the 20 nonessential amino acids, meaning that sufficient amounts are produced naturally in most people. Dietary sources of arginine include nuts, seeds, dairy, poultry, and seafood. According to Wikipedia, L-Arginine may have the following benefits (Source: http://en.wikipedia.org/wiki/L-arginine):

• Improving immune function
• Reducing risk of heart disease
• Increasing muscle mass
• Decreasing blood pressure

Arginine helps produce nitric oxide and creatine and stimulates the body’s production of protein (Source: http://www.mayoclinic.com/health/l-arginine/NS_patient-arginine).

Synonyms for Arginine listed on the Mayo Clinic’s website include 2-amino-5-guanidinopentanoic acid, dipeptide arginyl aspartate, HeartBars, ibuprofen-arginate, Sargenor, and Spedifen® (Source:http://www.mayoclinic.com/health/l-arginine/NS_patient-arginine).

Arginine Clinical Trials

No studies could be found that gave evidence for a direct effect of arginine on weight loss in humans. One study tested whether L-Arginine increased muscle mass and decreased fat tissue in swine. Only 24 swine were used and were randomly assigned to the L-Arginine group (1% L-Arginine added to diet) or an L-Alanine group (2.5% L-Alanine added to diet). After 60 days, the swine in the L-Arginine group had significantly increased body mass and skeletal-muscle but decreased fat content (Source: Amino Acids, e-publication, Aug 6, 2008).

Another study found that arginine stimulated secretion of the growth hormone which may help increase muscle mass in humans (Source:Journal of Clinical Endocrinology and Metabolism, 67(6), 1186-1189). However, the doses in the study were much higher than what is found in a typical supplement and were also administered in saline and through injection.

Conclusion

There is not enough concrete research to say if L-Arginine is effective as a diet pill ingredient. Also, it is unlikely that a supplement would provide a high enough dosage of L-Arginine to produce the effects found in a study.