l-Carnosine (beta-alanyl-L-histidine) occurs naturally in the body’s muscle and nervous tissues and is formed by the amino acids alanine and histidine. Levels of this dipeptide can decline with age. It is a water-soluble antioxidant and promotes cell health and cell longevity. In vitro, L-carnosine maintains healthy advanced glycation end-product, or AGE, activity. These end-products are formed when aldehydes (such as aldose and ketose sugars) and lipid peroxidation by-products bind to proteins. L-Carnosine plays a role in maintaining DNA integrity. L-Carnosine may also support superoxide dismutase activity. In addition, L-carnosine may help to maintain healthy peptide metabolism in the brain and its membrane-stabilizing properties support cellular health in the cardiovascular system. Some evidence suggests that the concentration of L-carnosine is an important factor in high-intensity exercise performance.