Pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate functions as an antioxidant in cosmetic products, and
is being used at concentrations up to 0.8%. Given the high molecular weight of this ingredient, skin penetration is not likely. It’s used as a stabilizer in skincare formulas so the product doesn’t break down when exposed to sunlight.
The available toxicity data, together with the low ingredient use concentrations, suggest that systemic toxicity would not be likely if percutaneous absorption were to occur. Additionally, the negative human repeated insult patch test data at at a concentration of 0.5% were deemed sufficient for evaluating the skin irritation and sensitization potential of pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate over the range of use concentrations in cosmetic products. The CIR Expert Panel concluded that pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate is safe in the present practices of use and concentration in cosmetics.