D-Aspartic Acid (DAA) is the newest natural testosterone booster on the market. DAA is the D-form of the amino acid aspartic acid. The body can produce DAA from the nonessential amino acid L-aspartic acid (the dietary form of aspartic acid). D-form amino acids, such as DAA, are found in higher concentrations in specific tissues in the body. For example, higher concentrations of DAA are found in the testes, pituitary gland, and hypothalamus (D'Aniello & Di Fiore 2000) all of which are areas involved in hormone production.