D-aspartic acid is one of two forms of the amino acid aspartic acid. The other form is L-aspartate.
The benefits of D-AA are specific to it, and do not extend to aspartic acid or L-aspartate.
D-AA can be used as a testosterone booster for infertile men, and by athletes as a temporary booster. Elevated testosterone levels only last a week to a week and a half in healthy men, with testosterone returning to normal afterward.
D-AA works in the central brain region to cause a release of hormones, such as luteinizing hormone, follicle-stimulating hormone, and growth hormone. It may also build up in the testicles, where it alleviates a rate-limiting step of testosterone synthesis, which leads to a minor testosterone increase.
Further research is needed on D-AA, as most studies attempt to assess D-AA’s role in the body under normal conditions, and not in the frame of supplementation.