1-(3-methoxybenzyl)-3-substituted thiourea antioxidant compounds and improved lipids compositions which are supplemented with amounts of such antioxidant compounds effective for augmenting oxidative stability of the base lipid are provided. Also provided are methods for enhancing the oxidative stability of a lipid comprising supplementing a base lipid in need of enhanced oxidative stability with at least one 1-(3-methoxybenzyl)-3-substituted thiourea compound of the present invention.