OPC stands for Oligomeric Proanthocyanidin, a type of flavonoid found in various plants, particularly in the bark of the pine tree, grape seeds, and certain fruits. It is known for its antioxidant properties, which help protect cells from damage caused by free radicals. Many people take OPC supplements for potential health benefits, including improved circulation and reduced inflammation. Research suggests that OPC may also support heart health and enhance skin appearance, although more studies are needed to confirm these effects.