Arginine is an essential amino acid that is found in most meats and proteins, however this key nutrient has been paired up with another amino acid complex alpha-keto-gluterate which is part of the krebs cycle of cellular respiration. Arinine AKG has long been though of as simply a nitric oxide precursor and hit the supplement industry by storm in the late 90′s. Still real science on this molecule is lacking when it comes to muscle building and nitric oxide production. That being said, many people swear by it as a “pump” facilitator and vasodialator.
Arginine AKG seems to be an ergogenic aid for both strength and endurance. In resistance trained men aged 30-50 it was shown to increase one rep max and wingate peak performance. It didn’t have an effect on body composition but that is something that is very tough to judge, since diet and exercise patterns vary greatly even in 8 weeks. (1) In this study it was also shown to be very safe when used as directed. Additionally in a second study, Arginine Alpha Keto-gluterate was shown to increase the ergogenic effects of creatine by boosting muscle power on the wingate test. This does show some validity to the practice of taking creatine and A-AKG supplements together. Arginine AKG also may improve insulin sensitivity and insulin signaling.
Arginine alone shows benefits on growth hormone release, nitric oxide levels and may benefit the bodybuilder in other ways. There is some controversy on Arginine supplements boosting nitric oxide levels, since in healthy humans it has not been shown to have this effect on its own. It could be that the addition of the alpha keto gluterate increases the N.O. effects or that other ingredients like norvaline and quercetin added into most N.O. supplements. Arginine may also stimulate mTOR similar to Leucine which could also have an anabolic effect in skeletal muscle.
Alpha keto gluterate may, on its own also have ergogenic activity but it may not be similar to glutamine in anabolism or catabolism. As a metabolite of Glutamine one would expect it to have similar properties, but no increase in muscle recovery was found in sick patients who took a alpha ketogluterate supplement (3). It is possible that the alpha ketogluterate only serves to protect the arginine molecule from arginase or increases cellular uptake.
One can’t deny the anecdotal feedback given to Arginine AKG products, but it’s tough to see on paper how this amino acid combination works to increase muscle mass. Still, with the constant stream of new products using this ingredient it’s clearly here to stay.
1. Campbell B, Roberts M, Kerksick C, Wilborn C, Marcello B, Taylor L, Nassar E, Leutholtz B, Bowden R, Rasmussen C, Greenwood M, Kreider R. Pharmacokinetics, safety, and effects on exercise performance of L-arginine alpha-ketoglutarate in trained adult men. Nutrition. 2006 Sep;22(9):872-81.
2. Little JP, Forbes SC, Candow DG, Cornish SM, Chilibeck PD. Creatine, arginine alpha-ketoglutarate, amino acids, and medium-chain triglycerides and endurance and performance. Int J Sport Nutr Exerc Metab. 2008 Oct;18(5):493-508.
3. Wirén M, Permert J, Larsson Alpha-ketoglutarate-supplemented enteral nutrition: effects on postoperative nitrogen balance and muscle catabolism J.Nutrition. 2002 Sep;18(9):725-8.
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. Glad you guys got things settled.
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