BHT

Also known as: Butylated hydroxytoluene, 2,6-Di-tert-butyl-4-methylphenol, E321

An oil-soluble antioxidant that protects formulas from oxidation, often confused with an antimicrobial preservative.

Editorial review by the IngredientWiki Editorial Team
Updated 2026-09-28
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1 min read
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Amber oil protected beneath a glass dome in a geometric still life — Editorial illustration

BHT, or butylated hydroxytoluene, is an antioxidant added in small amounts to oils, cosmetics, foods, and packaging to slow rancidity and color or odor changes. It protects the product rather than disinfecting it or acting as a skincare antioxidant treatment. Safety assessments set use conditions based on exposure; hazard headlines from high-dose animal studies do not describe ordinary cosmetic exposure by themselves.^{2, 3}

Protects oils from oxidation^{1, 2}
Not an antimicrobial preservative^{1, 2}
Usually used at low concentrations^{1, 2}
Risk assessment depends on dose and total exposure^{1, 2}

What is BHT?

BHT donates hydrogen to interrupt free-radical oxidation in a product's oil phase. That shelf-life role is distinct from delivering an antioxidant benefit to living skin.^{1, 2}

Where it comes from

Natural sources

Not normally extracted from a natural source for commercial formulas

How it's made

Commercial BHT is manufactured as a highly purified hindered phenolic antioxidant.

What it does in products

Benefits

Protects formula quality

moderate evidence

BHT slows oxidation that can produce rancid odors, color change, and degradation of oil-soluble components.^{2, 3}

This is a technical product-protection function and should not be presented as clinical antioxidant therapy.

Skin antioxidant benefit

insufficient evidence

Its presence as a stabilizer does not establish a meaningful anti-aging or skin-health outcome.²

Formula preservation and clinical skin endpoints are different questions.

Evidence scope and limitations

Low-level cosmetic formula use is emphasized; food exposure and occupational handling are distinguished.

Aggregate exposure changes with product category and geography.
Animal hazard doses cannot be mapped directly to routine topical use.

Evidence last checked: 2026-09-28

Side effects & safety

Irritation or contact allergy (rare)Reported reactions are uncommon at cosmetic use levels.

Safety considerations

No special topical warning is established at allowed cosmetic levels; total dietary and product exposure are addressed by regulators rather than label fear lists.
Not for: Known allergy to BHT

^{2, 3}

Amounts studied & product use

These figures describe research or common product use, not a personal dose or treatment recommendation.

In skincare studies and products

Used at low stabilizing levels; regional limits and exposure assumptions differ by product category.

^{2, 3}

Regulatory status

Permitted for specified food uses and used in cosmetics subject to general safety requirements; it is not a drug active.
INCI name on cosmetic labels: BHT.
CIR has assessed BHT as used in cosmetics.

^{4, 3}

Hazard is not the same as consumer risk

A hazard study asks whether an effect can occur under some exposure. A cosmetic risk assessment asks whether that effect is expected at the actual concentration, route, frequency, and combined exposure. Both pieces matter.

^{2, 3}

Frequently asked questions

Is BHT a preservative?

It preserves oils against oxidation, but it is not primarily an antimicrobial preservative.^{2, 3}

Is BHT banned in cosmetics?

No universal ban applies; permitted uses and concentration conclusions differ by jurisdiction and product exposure.^{2, 3}

The bottom line

BHT is a low-level formula antioxidant. Its safety question is an exposure assessment, not a yes-or-no judgment based on high-dose hazard alone.

References

Butylated hydroxytoluene: compound summary. PubChem, National Library of Medicine (2026) · ingredient monograph · CID 31404
Final report on the safety assessment of BHT. International Journal of Toxicology (2002) · safety assessment · PMID 12396675
SCCS scientific opinion on butylated hydroxytoluene (BHT) - SCCS/1636/21. Regulatory Toxicology and Pharmacology (2023) · safety assessment · PMID 36565917
FDA Authority Over Cosmetics: How Cosmetics Are Not FDA-Approved, but Are FDA-Regulated. U.S. Food and Drug Administration (2013) · government guidance

Revision history

2026-09-28Initial publication with claim-level citations, formulation limits, safety context, and editorial evidence review.