Effects and Dosage of Arginine and AAKG: What's Myth and What's Reality?

The food supplement arginine (L-arginine) and its variations such as arginine alpha-ketoglutarate (AAKG) are still among the popular food supplements in the world of sports nutrition. This amino acid is linked in the body with a range of key processes, from the production of hormones to improved blood flow to the working muscles. But what do scientific sources say about how effective it really is? Does it make any sense to supplement with it at all?

What are arginine and alpha-ketoglutarate?

From a chemical point of view, arginine is a non-essential amino acid, which means that the human body can synthesise it itself.

Alpha-ketoglutarate (α-ketoglutarate) is a keto acid which arises as an intermediate in the TCA cycle (Krebs cycle) – the metabolic pathway in which cells convert nutrients into energy. At the same time it takes part in the metabolism of amino acids, because in reactions called transamination it can accept a nitrogen group from amino acids and be converted, for example, into glutamate.

What effects are attributed to arginine and at what doses?

Citrulline: a better alternative to arginine

A far more suitable alternative is L-citrulline, because the body can convert it directly into arginine. According to current scientific data it has a greater effect than L-arginine itself and moreover it does not cause digestive problems (cramps and diarrhoea) at the same doses of 6 g (Viribay et al. 2022).

Conclusion for athletes

Taking arginine orally at the usual doses of 1–2 g does not lead to increased secretion of growth hormone or insulin. Increased insulin secretion can be achieved by eating carbohydrates, and a far greater increase in plasma growth hormone is achieved by exercise itself.

Arginine can be used to produce nitric oxide (NO), but there is only limited evidence that supplementing with arginine increases sports performance, and it has not been shown that any effect it may have is connected with changes in NO production. What is more, L-citrulline is more effective in this respect.

From a practical point of view, arginine as a food supplement – whether in the pure form of L-arginine or in the AAKG compound – is completely ineffective and unnecessary for supporting physical performance or building muscle.

1. Knopf RF, Conn JW, Floyd JC Jr., et al. (1966). The normal endocrine response to ingestion of protein and infusions of amino acids. Trans Assoc Am Physicians, 79:312–321.
2. Dupre J, Curtis JD, Waddell RW, Beck JC. (1968). Alimentary factors in the endocrine response to administration of arginine in man. Lancet, 2(7558):28–29.
3. Lambert MI, Hefer JA, Millar RP, Macfarlane PW. (1993). Failure of commercial oral amino acid supplements to increase serum growth hormone concentrations in male body-builders. Int J Sport Nutr, 3(3):298–305.
4. Fogelholm GM, Naveri HK, Kiilavuori KT, Harkonen MH. (1993). Low dose amino acid supplementation: No effects on serum growth hormone and insulin.
5. Bailey SJ, Winyard P, Vanhatalo A, et al. (2010). Acute L-arginine supplementation reduces the O₂ cost of moderate-intensity exercise and enhances high-intensity exercise tolerance. J Appl Physiol, 109(5):1394–1403.
6. Buford BN, Koch AJ. (2004). Glycine-arginine-alpha-ketoisocaproic acid improves performance of repeated cycling sprints. Med Sci Sports Exerc, 36(4):583–587.
7. Viribay A, Fernández-Landa J, Castañeda-Babarro A, et al. (2022). Effects of citrulline supplementation on different aerobic exercise performance outcomes: A systematic review and meta-analysis. Nutrients, 14(17):3479.
8. Jeukendrup A, Gleeson M. (2025). Sport nutrition (4th ed.). Human Kinetics.