SAMe is an amino acid derivative that can become depleted in your body through illness or age. The highest concentrations are in the liver, where it supports liver health and large numbers of complex enzymatic reactions – and your brain, where it is required for the synthesis of norepinephrine, dopamine, and serotonin. These brain chemicals are responsible for your energy level and mood. SAMe is also a major component in the synthesis of nucleic acids, proteins, hormones, and phospholipids. It was proven in a 2002 U.S. Department of Health and Human Services study to be effective in helping maintain both mood stability and joint function.