Arginine alpha-ketoisocaproate (AAKIC) is a compound that combines the amino acid L-arginine with alpha-ketoisocaproate, a metabolite of the amino acid leucine. Its use in muscle support, particularly in sports nutrition and bodybuilding supplements, is primarily based on the theoretical benefits of its components. Arginine is known to be a precursor to nitric oxide, which can aid in vasodilation and potentially enhance blood flow to muscles during exercise. Alpha-ketoisocaproate may play a role in reducing muscle breakdown (catabolism) by serving as a keto acid that can be converted back into leucine or used for energy production.

However, direct scientific evidence supporting the use of AAKIC specifically for muscle growth or improved muscle function is limited. A few small studies have examined its effects in athletes, with mixed or modestly positive results. For example, some research suggests it might reduce muscle protein breakdown during intense exercise, but these effects are not robustly demonstrated across large, well-designed trials. Most of the supportive evidence is extrapolated from what is known about arginine and leucine individually, rather than from studies on AAKIC itself.

In summary, while there is a scientific rationale for AAKIC’s use in muscle support, the direct evidence is not strong, and its effectiveness remains uncertain pending further research.