Jacques Masquelier (aka Jack Masquelier, born in 1922 in Paris, died 24 February 2009) is a French scientist. He is the discoverer of oligomeric proanthocyanidins or OPCs.
One was discovered by Professor Jacques Masquelier and called Vitamin P, although this name did not gain official category status and has since fallen out of usage. It was Masquelier who first developed techniques for the extraction of proanthocyanidins from certain plant species. In 1948, Masquelier discovered oligomeric proanthocyanidins on the skin of a peanut by accident.