Lactic acid

Lactic acid is a small, chiral, alpha-hydroxy acid produced naturally in tissues (especially muscle) under anaerobic conditions, when pyruvate is reduced by lactate dehydrogenase. It exists in two enantiomeric forms (L-lactic acid and D-lactic acid). Lactic acid acts as both an energy substrate and a signaling molecule, influencing metabolic flux between glycolysis, gluconeogenesis, and fatty acid metabolism. It also plays roles in industrial fermentation, food preservation, and as a biomarker of tissue hypoxia or metabolic dysfunction. In medicine, blood lactic acid levels are used to monitor for lactic acidosis, commonly associated with sepsis, hypoperfusion, mitochondrial diseases, or intense exercise. Importantly, lactic acid itself is not a receptor, enzyme, transporter, or direct pharmacological target, but rather a key metabolic intermediate and signal.

Other names

2-hydroxypropanoic acidDL-lactic acidmilk acidsarcolactic acid (muscle-derived L-lactic acid)2-hydroxypropionic acid