BHT stands for butylated hydroxytoluene, which is a synthetic antioxidant used in a wide range of cosmetic formulations as a preservative and stabilizer. It is used to prevent the oxidation of products, particularly the fatty phase of formulas that are likely to degrade when exposed to air. BHT is found in various cosmetic products, including certain formulas containing fats or in aqueous emulsions containing certain active ingredients or plant extracts. It is used at concentrations ranging from 0.0002% to 0.5% . BHT does penetrate the skin, but the relatively low amount absorbed remains primarily in the skin. Although there were only limited studies that evaluated the effect of BHT on the skin, the available studies, along with the case literature, demonstrate no significant irritation, sensitization, or photosensitization. The safety of BHT in cosmetics has been assessed, and it is considered safe for use in cosmetics at the regulated concentration levels.