BHT
Synthetic antioxidant preservative. Protects oils and other lipid formula components from rancidity. Used in microdoses in cosmetics.
Evidence by route
Topical application
The CIR deemed BHT safe at cosmetic concentrations up to 0.5%. Contact allergy is rare. Systemic toxicity concerns relate to food, not cosmetic, use.
How to read tiers A–F
- CWeak evidence. In vitro data, open-label studies, or expert consensus
Tolerability and safety
- Irritation potential
- Low
- Allergen risk
- Low
- Pregnancy
- Safe
- Suitable for
- Oily, Dry, Sensitive, Combination, Normal
About this ingredient
BHT (Butylated Hydroxytoluene) is a synthetic phenolic antioxidant. In food (E321) and cosmetics it protects oils, fatty formula components, and UV filters from oxidation and rancidity. Mechanism. Neutralises free radicals that form when oils contact air and under UV light. Does not act as a skin active on its own: BHT's job is to extend formula shelf life. Where applied. Creams, balms, lipsticks, sunscreens, hair products. Cosmetic concentration 0.01–0.1% – a microdose sufficient to stabilise the lipid phase. In Spain part of Heliocare, La Roche-Posay Anthelios, ISDIN Fotoprotector sunscreens. Safety. SCCS opinion 2021 considered BHT safe at cosmetic concentrations. EFSA confirmed food-additive safety at the set doses (up to 0.25 mg/kg/day). Contact allergy is rare (<0.5% in patch tests). Concerns about endocrine and carcinogenic activity at high oral doses in animal models do not reproduce at cosmetic microdoses on skin. Greenwashing and controversy. BHT is a frequent target of 'natural cosmetics' marketing labelling it a 'hazardous synthetic'. At regulator level SCCS and FDA hold a stable position: safe at the concentrations in use. Alternative – tocopherol (vitamin E), but it oxidises faster itself and often needs additional protection. Pregnancy and lactation – safe. AEMPS does not restrict topical use at cosmetic concentrations. Functional role. An auxiliary formula antioxidant, not a cosmetic active. Protects the formula from rancidity; does not act on skin.
Frequently asked questions
Is BHT safe during pregnancy?
BHT is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
What skin types is BHT for?
BHT suits: oily, dry, sensitive, combination, normal.
What is BHT and what does it do in cosmetics?
Synthetic antioxidant preservative.
What's the INCI name for BHT?
The INCI name is BHT.
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