EWG Skin Deep Hazard Score:
What is it:
TBHQ is a phenolic preservative and stabilizer used in cosmetics, varnishes, lacquers, and resins.
What are its risks:
- A number of animal studies have found it to be mutagenic or carcinogenic at high doses. (Source)(Source)
- Potential skin or eye irritant at full strength. (Source)
TBHQ is a phenol, so it does have the potential to interfere with the way estrogen and estrogen receptors work in the body. There have been no studies to asses the possible estrogenic activity of this chemical. Couple this fact with its potentially mutagenic properties, and I'd deem this an ingredient to avoid.