Pentaerythrityl Tetra-Di-T-Butyl Hydroxyhydrocinnamate Good Antioxidant No known benefits Pentaerythrityl Tetra-Di-T-Butyl Hydroxyhydrocinnamate at a glance Synthetic ingredient that works as an antioxidant Helps ensure consistent efficacy and stability of other antioxidants Prevents unwanted colour changes in cosmetics Works best in products that contain fats and oils Pentaerythrityl Tetra-Di-T-Butyl Hydroxyhydrocinnamate description Pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate is a synthetic, odorless antioxidant often added to skin care formulas such as sunscreens to ensure consistent efficacy and stability of other, more fragile antioxidants. A little goes a long way: the recommended usage level of pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate is between 0.01-0.1%. The safety assessment of this ingredient looked at concentrations from 0.0001%-0.8% as used in leave-on products. It’s typically used in concentrations of 0.5% or less in rinse-off formulas. Its oil-soluble nature means it pairs best with other oils and fats in a formula. Although it is available and can be used on its own, this antioxidant is commonly used in a blend with other ingredients such as emollient squalane and film-forming polymers as more of a “total package” of stability, texture enhancing, creating stick formulas (as in lipstick and sunscreen sticks), and also serving as an alternative to silicone ingredients. It is frequently used to protect natural oils, fragrances, and butters from oxidation. The high molecular weight of pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate does not penetrate past skin’s surface. It is considered safe as used in cosmetics.