δ-Tocopherol is a naturally occurring form of vitamin E and a lipophilic antioxidant found in vegetable oils, nuts, and seeds. It functions by scavenging free radicals and inhibiting lipid peroxidation in cell membranes and food systems. As the least methylated tocopherol, it exhibits distinct bioavailability and antioxidant potency compared to α-tocopherol. It is commonly used as a food additive (E309) to extend shelf life and prevent rancidity. δ-Tocopherol is absorbed via the lymphatic system and metabolized in the liver, with lower plasma retention than other tocopherols. Research indicates potential anti-inflammatory and chemopreventive properties, though it is primarily valued for its role in stabilizing polyunsaturated fats.