Tochopherol is Vitamin E in the alcohol form; a hydroxyl group (-OH) is positioned on the aromatic ring at position 6. This hydroxyl group acts as a hydrogen donor which allows for the antioxidant effect of Vitamin E, limiting free-radical damage to other molecules. Because the hydroxyl group of Vitamin E gives itself up to oxidation so readily, tocopherols degrade when exposed to oxygen, high temperatures or metal ions. In order or maintain stability tocopherols should be stored in airtight containers and at cool temperatures.