Arginine alpha-ketoglutarate (AAKG) is a dietary supplement commonly promoted for bodybuilding due to its supposed ability to enhance nitric oxide (NO) production, leading to increased blood flow, improved nutrient delivery to muscles, and enhanced exercise performance. The theoretical basis comes from the role of L-arginine as a precursor for nitric oxide synthesis, and alpha-ketoglutarate as a metabolic intermediate in the Krebs cycle, potentially supporting energy production.

However, scientific evidence supporting the efficacy of AAKG for bodybuilding is weak. Clinical studies investigating AAKG supplementation in resistance-trained athletes have generally shown little to no significant benefit in terms of muscle strength, muscle mass, endurance, or recovery compared to placebo. For example, a study published in the International Journal of Sport Nutrition and Exercise Metabolism (2006) found no improvement in muscle performance or body composition in resistance-trained men after AAKG supplementation. Similarly, a 2012 review concluded that the evidence for L-arginine or AAKG's ergogenic effects is insufficient and inconsistent.

In summary, while the use of AAKG in bodybuilding is based on plausible mechanisms and is widespread, current scientific evidence does not robustly support its effectiveness for increasing muscle mass or strength. Most authoritative reviews rate the quality and quantity of supportive evidence as low.