Margaric acid (Heptadecanoic acid, C17) is a fatty acid of exogenous (primarily ruminant) origin. Many "odd" length long chain amino acids are derived from the consumption of dairy fats (milk and meat). Heptadecanoic acid constitutes 0.61% of milk fat and 0.83% of ruminant meat fat. The content of heptadecanoic acid in the subcutaneous adipose tissue of humans appears to be a good biological marker of long-term milk fat intake in free-living individuals in populations with high consumption of dairy products. Margaric acid is a metabolite in glutamate and lipid metabolism in vivo. Blood-brain barrier permeable. Orally active. Possibly involved in anti-tumor activity.