BHT

BHT (Butylated Hydroxytoluene) is a synthetic, lipid-soluble phenolic antioxidant derived from petroleum-based precursors, widely used in cosmetics to prevent oxidative rancidity in oils, fats, and waxes. It functions by donating hydrogen atoms to free radicals, effectively interrupting the chain reaction of lipid peroxidation and extending the shelf life of oil-containing formulations. Formulators favor BHT for its low cost, high stability across a wide temperature range, and proven efficacy at very low use concentrations (typically 0.01–0.1%), though it has faced scrutiny over potential endocrine-disrupting properties and is restricted or subject to labeling requirements in some markets.