Aspartic acid, also known as L-aspartate, is thought to help promote a robust metabolism, and is sometimes used to treat fatigue and depression. Aspartic acid plays an important role in the citric acid cycle, or Krebs cycle, during which other amino acids and biochemicals, such as asparagine, arginine, lysine, methionine, threonine, and isoleucine, are synthesized. Aspartic acid gets its reputation as a treatment for chronic fatigue from the crucial role it plays in generating cellular energy. Aspartic acid moves the coenzyme nicotinamide adenine dinucleotide (NADH) molecules from the main body of the cell to its mitochondria, where it is used to generate adenosine triphosphate (ATP), the fuel that powers all cellular activity. spartic acid keeps your mind sharp by increasing concentrations of NADH in the brain, which is thought to boost the production of neurotransmitters and chemicals needed for normal mental functioning. It also removes excess toxins from the cells, particularly ammonia, which is very damaging to the brain and nervous system as well as the liver.