Ingredient dictionary

BHT

Also listed as: Butylated hydroxytoluene, Butylhydroxytoluene

BHT is a synthetic antioxidant that slows down oxidation, the process that makes oils and fats turn stale or rancid over time. It is on the label of 87 products in our library. Checked against our library November 6, 2026.

What BHT does

Slows oxidation in oils and fats
Helps keep smell and color stable
Extends the shelf life of formulas

BHT is made through a chemical process rather than taken from plants. Its starting materials are petrochemical, and the result is a white, crystal-like solid that dissolves in oils. Formulators add it to protect the oily parts of a product from going stale.

Oxidation happens when air, heat or light reacts with fats, slowly changing their smell and color. BHT steps in and interrupts that reaction, so the formula stays fresher for longer. It doesn't noticeably change how a product feels or spreads, and it is usually a small part of the formula.

Good for

Suits formulas that contain oils, fats or waxes, such as sunscreens, lotions and mascara, where freshness matters.

Frequently asked questions

Is BHT safe in skincare?

BHT is an antioxidant used at low levels in many cosmetics. It is generally considered well tolerated, though a few people may react to any ingredient. If you have sensitive skin, patch testing a new product is a sensible step.

Does BHT act as a preservative?

No, not in the same way. BHT slows oxidation, which is the slow spoiling of oils. It does not stop bacteria or mold, so products usually also need a separate preservative system to stay safe.