D- Aspartic Acid or D-AA, as it is commonly called, is a non-essential amino acid. It is produced by the body in the pituitary glands and in the hypothalamus. We all know that amino acids are the foundation of proteins and play a crucial role in the growth of humans. It is a proven testosterone booster and contributes handsomely in muscle building, both properties that are irresistible to most men. However, with time and age, the rate of production of D- Aspartic Acid decreases considerably and your body is left without any.