Arginine-L-malate is a compound combining the amino acid L-arginine and malic acid. It is often marketed as a sports supplement purported to enhance exercise performance, primarily based on the known roles of its constituents. L-arginine serves as a precursor for nitric oxide (NO), a molecule that can promote vasodilation and potentially improve blood flow, while malic acid is involved in the Krebs cycle, contributing to cellular energy production. The theoretical rationale is that together, these compounds may improve endurance, reduce fatigue, and support recovery.

Scientific evidence for these claims, however, is limited. Some small studies have shown that L-arginine supplementation can increase NO production and marginally improve exercise performance, but results are inconsistent and often confounded by study design, dosage, and population differences. Malate (often studied as part of arginine malate or citrulline malate) has some evidence for reducing fatigue, but the data are stronger for citrulline malate than arginine malate. There are few, if any, high-quality clinical trials specifically investigating Arginine-L-malate as a compound for exercise performance in humans.

Overall, while the use of Arginine-L-malate has a plausible scientific basis, current direct evidence supporting its effectiveness for enhancing exercise performance is weak to moderate (rating 2 out of 5). More rigorous, targeted research is needed to confirm its benefits.