BHT
Butylated Hydroxytoluene
What it is
A synthetic phenolic antioxidant (CAS 128-37-0) added to formulas to prevent oxidation of oils and fats, extending shelf stability.
In this product: Antioxidant preservative.
Dose & route, what actually matters
Dermal, leave-on application to underarm skin. Potential for skin absorption; also present in some sunscreens (leave-on facial).
EUROPEAN UNION
SCCS Opinion SCCS/1636/21 (December 2021) concluded BHT safe up to 0.8% in leave-on and rinse-off products while explicitly flagging 'concerns related to potential endocrine disrupting properties.' UK formally restricted BHT in all cosmetic categories under SI 2024/455 (April 2024) with maximum concentration limits.
UNITED STATES
No concentration restriction or endocrine disruptor designation for BHT in cosmetics. Broadly permitted as a cosmetic antioxidant with no concentration cap.
The evidence
SCCS/1636/21 (2021): 'In light of the data provided and taking under consideration the concerns related to potential endocrine disrupting properties of BHT ... the SCCS is of the opinion that BHT is safe as an ingredient up to a maximum concentration of 0.8% in other leave-on and rinse-off products.'
regulatory · 2021 · source
UK Cosmetic Products (Restriction of Chemical Substances) Regulations 2024 (SI 2024/455) formally restricted BHT in all cosmetic categories effective April 2024.
regulatory · 2024 · source
California Prop 65: Not listed.
How to avoid it
Look for BHT or Butylated Hydroxytoluene in the inactive ingredients list. Most mineral-based or clean-label products omit it.
Where it hides
Editorial analysis of publicly available regulatory and peer-reviewed sources. Not medical advice. We name our evidence and link it, including when an ingredient is fine.