BHT

The abbreviation for butylated hydroxytoluene 

Potent synthetic antioxidant 

Helps keep delicate ingredients stable 

Considered safe as used in cosmetics

BHT is Butylated hydroxytoluene, a potent synthetic antioxidant sometimes used to help stabilize light- and air-sensitive cosmetic ingredients such as retinol and unsaturated fatty acids.

BHT is also globally approved for use as a food-grade preservative, where its antioxidant action keeps foods fresher longer. Amounts of 0.02% or less are considered safe for this use; however, controversial reports have been published since the 1970s that digestive metabolites of BHT could cause health problems.

The amount of BHT uses in cosmetic products is typically 0.0002%-0.5%. Such low amounts do not pose a risk to skin (indeed, the safety assessment found BHT was non-irritating) nor does it penetrate skin far enough to be absorbed into the bloodstream. The European Union’s Scientific Committee on Consumer Safety concluded in December 2021 that “BHT is safe as an ingredient up to a maximum concentration of 0.8% in other leave-on and rinse-off products.”