Mixed tocopherols are a blend of the natural forms of vitamin E (alpha, beta, gamma, delta) used to prevent fat rancidity in pet food. Typically derived from soybean or sunflower oil. They are the dominant natural alternative to synthetic preservatives like BHA, BHT, and ethoxyquin in premium pet food. Effective antioxidant, no documented health concerns, and contributes a small amount toward the dietary vitamin E requirement. Look for "mixed tocopherols," "tocopherols," or "natural mixed tocopherols" near the end of the ingredient list — usually adjacent to other supplements.