Body & Beauty / Compounds / Butylated hydroxytoluene (BHT)

Butylated hydroxytoluene (BHT) on your skin: a safety profile

Low risk

(People-specific data is limited; this page draws from human adult context.) Butylated hydroxytoluene (BHT; 2,6-di-tert-butyl-4-methylphenol) is a synthetic antioxidant used as a food preservative (FDA GRAS), in packaging materials, cosmetics, rubber, and petroleum products. BHT is one of the most extensively used food additives globally, present in breakfast cereals, snack foods, oils, and processed foods at concentrations permitted by FDA (typically 0.0002% of fat content in food). IARC Group 3 (not classifiable as to carcinogenicity in humans; Monograph 40, 1986). At permitted food use levels, BHT does not present a meaningful carcinogenic risk to adults. High-dose animal studies have demonstrated contradictory effects — BHT at very high doses (≥250 mg/kg/day in rodents) showed both promotional and inhibitory effects on various tumor types depending on species, sex, and target organ. This complexity is reflected in the IARC Group 3 classification. The Acceptable Daily Intake (ADI) established by JECFA is 0–0.3 mg/kg bw/day for BHT; typical dietary exposure from food is well below this. BHT is also used as a preservative in some pharmaceuticals and cosmetics; repeated dermal application can cause contact sensitization in a small proportion of individuals. At current exposure levels in food, BHT is considered safe for adults by major regulatory authorities.

What is butylated hydroxytoluene (bht)?

The IUPAC name is 2,6-ditert-butyl-4-methylphenol.

Also known as: 2,6-ditert-butyl-4-methylphenol, 2,6-Di-tert-butyl-4-methylphenol, 2,6-Di-tert-butyl-p-cresol, Butylhydroxytoluene.

IUPAC name
2,6-ditert-butyl-4-methylphenol
CAS number
128-37-0
Molecular formula
C15H24O
Molecular weight
220.35 g/mol
SMILES
CC1=CC(=C(C(=C1)C(C)(C)C)O)C(C)(C)C
PubChem CID
31404

Risk for people

Low risk

Butylated hydroxytoluene (BHT; 2,6-di-tert-butyl-4-methylphenol) is a synthetic antioxidant used as a food preservative (FDA GRAS), in packaging materials, cosmetics, rubber, and petroleum products. BHT is one of the most extensively used food additives globally, present in breakfast cereals, snack foods, oils, and processed foods at concentrations permitted by FDA (typically 0.0002% of fat content in food). IARC Group 3 (not classifiable as to carcinogenicity in humans; Monograph 40, 1986). At permitted food use levels, BHT does not present a meaningful carcinogenic risk to adults. High-dose animal studies have demonstrated contradictory effects — BHT at very high doses (≥250 mg/kg/day in rodents) showed both promotional and inhibitory effects on various tumor types depending on species, sex, and target organ. This complexity is reflected in the IARC Group 3 classification. The Acceptable Daily Intake (ADI) established by JECFA is 0–0.3 mg/kg bw/day for BHT; typical dietary exposure from food is well below this. BHT is also used as a preservative in some pharmaceuticals and cosmetics; repeated dermal application can cause contact sensitization in a small proportion of individuals. At current exposure levels in food, BHT is considered safe for adults by major regulatory authorities.

Regulatory consensus

11 regulatory and scientific bodies have classified Butylated hydroxytoluene (BHT). The classifications differ — that's the data.

AgencyYearClassificationNotes
IARC—Group 3
EPA CTX / IARC—Group 3 - Not classifiable as to its carcinogenicity to humans
EPA CTX / Genetox—Genotoxicity: positive (Ames: positive, 83 positive / 15 negative reports)
EPA CTX / Genetox—Genotoxicity: positive (Ames: positive, 83 positive / 15 negative reports)
EPA CTX / Skin-Eye—Skin Irritation: SkinIrr2 (score: high)
EPA CTX / Skin-Eye—Eye Irritation: Category 2B (score: moderate)
EPA CTX / Skin-Eye—Skin Irritation: Not classified (score: low)
EPA CTX / Skin-Eye—Skin Sensitization: Category 6.5B (Category 1) (score: moderate)
EPA CTX / Skin-Eye—skin sensitisation: in vivo (non-LLNA): Not likely to be sensitizing (score: low)
EPA CTX / Skin-Eye—eye irritation: in vivo: Studies Indicate No Significant Irritation (score: low)
EPA CTX / Skin-Eye—skin irritation: in vivo: Studies Indicate No Significant Irritation (score: low)

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where you encounter butylated hydroxytoluene (bht)

  • Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
  • Occupational Environments — Factories, Warehouses, Transportation vehicles
  • Personal Care — shampoo, conditioner, lotion, cosmetics, sunscreen

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Butylated hydroxytoluene (BHT):

  • Fragrance-free formulations
    Trade-offs: Consumer preference for scented products
    Relative cost: Lower (ingredient elimination)
  • Essential oil-based fragrances (with disclosure)
    Trade-offs: Natural does not mean safe — many essential oils are skin sensitizers
    Relative cost: 2-5× conventional

Frequently asked questions

What products contain butylated hydroxytoluene (bht)?

Butylated hydroxytoluene (BHT) appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments); shampoo (Personal care).

Why do regulators disagree about butylated hydroxytoluene (bht)?

Butylated hydroxytoluene (BHT) has been classified by 11 agencies including IARC, EPA CTX / IARC, EPA CTX / Genetox, EPA CTX / Genetox, EPA CTX / Skin-Eye, with differing conclusions. Regulators apply different standards of evidence (animal data weighting, exposure-pattern assumptions, epidemiological power thresholds), which is why two scientific bodies can review the same data and reach different conclusions. See the regulatory consensus table on this page for the full picture.

See Butylated hydroxytoluene (BHT) in the body app

Look up products containing butylated hydroxytoluene (bht), compare to alternatives, and explore the full data record.

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Sources (2)
  1. IARC Monographs Volume 40: Some Naturally Occurring and Synthetic Food Components — BHT Group 3 Evaluation (Not Classifiable as to Carcinogenicity) (1986) — regulatory
  2. US FDA: Butylated Hydroxytoluene (BHT) — GRAS Affirmation, Acceptable Daily Intake, and Food Additive Regulations (21 CFR 172.115) (2020) — regulatory

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →