OPC is an abbreviation found on many labels and rarely explained. It stands for oligomeric proanthocyanidins: a group of plant tannins, chemically related to the tannins in wine and tea. They occur in grape seeds, pine bark, apple seeds and peanut skins – and they are the reason red wine leaves a dry, furry feeling in the mouth.
From by-product to raw material
Winemaking leaves behind pomace – the skins, stems and seeds that remain after pressing. OPC is extracted from the dried seeds. The French researcher Jacques Masquelier first isolated the compounds in the 1940s, initially from pine bark and later from grape seeds. The term that is still used today goes back to him.
Why «oligomeric» matters
Proanthocyanidins are made up of building blocks that link into chains of different lengths. «Oligomeric» means short-chain – two to about five building blocks. Long chains, the polymeric forms, are strongly astringent and barely absorbed; the short ones are what it is all about. An extract without a stated OPC content therefore tells you little.
The combination with vitamin C
OPC and vitamin C are almost always sold together. The background is historical: Masquelier originally studied proanthocyanidins in connection with the factors then referred to as «vitamin P», which always occur alongside vitamin C in the same fruits. Our organic OPC grape seed powder contains both as well.
Related
You will find OPC under Botanicals, and by topic under Heart & Circulation and Skin, Hair & Nails.
Note
Tannins can reduce the absorption of iron from plant sources – so do not take OPC at the same time as an iron supplement, but a few hours apart. Food supplements are not a substitute for a varied diet; do not exceed the stated daily dose. If you are pregnant or breastfeeding, have a pre-existing condition or take medication, seek medical advice.
