There are enormous differences in quality with OPC. The bioavailability of the virgin material is crucial for its effectiveness. Only short-chain OPC's guarantee that.
In the 1940s Prof. Masquelier started with his research in the University of Bordeaux. He won the first OPC from peanut skins.
OPC-DOC compares 4 of the most well-known OPC compounds on the basis of 5 scientific factors. Test winner is Pinovinol® OPC-Formula.