A 2008 review ascertained that the impact of aspartate on endurance seems generally favourable in humans. The main outcomes of aspartate supplementation are attenuation of exercise-induced hyperammonemia and an increase of exercise endurance. In studies reporting increased endurance, no correlation has been found between its dosage and the increment of exercise time. Mechanisms supposed to explain the ergogenic effect of aspartate have also been reviewed in this article. Claims of a glycogen-sparing action, reduced hyperammonemia and a higher rate of free fatty acid oxidation have not been confirmed unequivocally by the literature.
Trudeau F. (2008). Aspartate as an ergogenic supplement. Sports medicine (Auckland, N.Z.), 38(1), 9–16. https://doi.org/10.2165/00007256-200838010-00002