TBHQ (tert-Butylhydroquinone) on your skin: a safety profile
Low risk(People-specific data is limited; this page draws from human adult context.) TBHQ (tert-Butylhydroquinone) is a synthetic phenolic antioxidant used to extend the shelf life of fats, oils, and fat-containing foods by inhibiting lipid oxidation rancidity. It is one of four primary synthetic antioxidants approved in US food (alongside BHA, BHT, and propyl gallate). FDA permits TBHQ at up to 0.02% of the fat or oil content of food; EU permits it as E319 at 100–200 mg/kg in specified fat-containing foods. TBHQ is not classified as a carcinogen by IARC. Animal studies at high doses have shown liver effects (increased organ weight, microsomal enzyme induction) and precancerous lesions (forestomach papillomas) in rodent species with a non-glandular forestomach anatomy not present in humans; FDA and EFSA assessments concluded these findings are not predictive of human cancer risk at permitted use levels. The WHO/JECFA ADI is 0–0.7 mg/kg bw/day. Dietary exposure from TBHQ-containing foods at permitted use levels is well within the ADI; TBHQ-containing products include fast food frying oils, crackers, chips, and microwave popcorn. A 2020 EFSA re-evaluation confirmed the ADI and safety of TBHQ at permitted EU use levels. The Environmental Working Group (EWG) lists TBHQ as a food additive of concern, citing animal studies; the scientific regulatory consensus disagrees with characterizing TBHQ as hazardous at dietary exposure levels.
What is tbhq (tert-butylhydroquinone)?
The IUPAC name is 2-tert-butylbenzene-1,4-diol.
Also known as: 2-tert-butylbenzene-1,4-diol, tert-Butylhydroquinone, TBHQ, 2-tert-Butylhydroquinone.
- IUPAC name
- 2-tert-butylbenzene-1,4-diol
- CAS number
- 1948-33-0
- Molecular formula
- C10H14O2
- Molecular weight
- 166.22 g/mol
- SMILES
- CC(C)(C)C1=C(C=CC(=C1)O)O
- PubChem CID
- 16043
Risk for people
Low riskTBHQ (tert-Butylhydroquinone) is a synthetic phenolic antioxidant used to extend the shelf life of fats, oils, and fat-containing foods by inhibiting lipid oxidation rancidity. It is one of four primary synthetic antioxidants approved in US food (alongside BHA, BHT, and propyl gallate). FDA permits TBHQ at up to 0.02% of the fat or oil content of food; EU permits it as E319 at 100–200 mg/kg in specified fat-containing foods. TBHQ is not classified as a carcinogen by IARC. Animal studies at high doses have shown liver effects (increased organ weight, microsomal enzyme induction) and precancerous lesions (forestomach papillomas) in rodent species with a non-glandular forestomach anatomy not present in humans; FDA and EFSA assessments concluded these findings are not predictive of human cancer risk at permitted use levels. The WHO/JECFA ADI is 0–0.7 mg/kg bw/day. Dietary exposure from TBHQ-containing foods at permitted use levels is well within the ADI; TBHQ-containing products include fast food frying oils, crackers, chips, and microwave popcorn. A 2020 EFSA re-evaluation confirmed the ADI and safety of TBHQ at permitted EU use levels. The Environmental Working Group (EWG) lists TBHQ as a food additive of concern, citing animal studies; the scientific regulatory consensus disagrees with characterizing TBHQ as hazardous at dietary exposure levels.
Regulatory consensus
12 regulatory and scientific bodies have classified TBHQ (tert-Butylhydroquinone). The classifications differ — that's the data.
| Agency | Year | Classification | Notes |
|---|---|---|---|
| EPA CTX / Genetox | — | Genotoxicity: positive (Ames: positive, 27 positive / 14 negative reports) | |
| EPA CTX / Genetox | — | Genotoxicity: positive (Ames: positive, 27 positive / 14 negative reports) | |
| EPA CTX / Skin-Eye | — | Skin Irritation: SkinIrr2 (score: high) | |
| EPA CTX / Skin-Eye | — | Skin Sensitization: SkinSens1 (score: high) | |
| EPA CTX / Skin-Eye | — | Skin Sensitization: Category 1 (score: high) | |
| EPA CTX / Skin-Eye | — | Eye Irritation: Category 6.4A (Category 2A) (score: high) | |
| EPA CTX / Skin-Eye | — | Skin Irritation: Category 6.3A (Category 2) (score: high) | |
| EPA CTX / Skin-Eye | — | Skin Sensitization: Category 6.5B (Category 1) (score: moderate) | |
| EPA CTX / Skin-Eye | — | skin irritation: in vivo: Severe Irritation (score: high) | |
| EPA CTX / Skin-Eye | — | skin sensitisation: Not likely to be sensitizing (score: low) | |
| 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: Severe Irritation (score: high) |
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 tbhq (tert-butylhydroquinone)
- 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 TBHQ (tert-Butylhydroquinone):
-
Fragrance-free formulations
Trade-offs: Consumer preference for scented productsRelative cost: Lower (ingredient elimination)
-
Essential oil-based fragrances (with disclosure)
Trade-offs: Natural does not mean safe — many essential oils are skin sensitizersRelative cost: 2-5× conventional
Frequently asked questions
What products contain tbhq (tert-butylhydroquinone)?
TBHQ (tert-Butylhydroquinone) 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 tbhq (tert-butylhydroquinone)?
TBHQ (tert-Butylhydroquinone) has been classified by 12 agencies including EPA CTX / Genetox, EPA CTX / Genetox, EPA CTX / Skin-Eye, EPA CTX / Skin-Eye, 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 TBHQ (tert-Butylhydroquinone) in the body app
Look up products containing tbhq (tert-butylhydroquinone), compare to alternatives, and explore the full data record.
Open in body View raw API dataSources (2)
- US FDA: TBHQ (tert-Butylhydroquinone) — 21 CFR 172.185, Permitted Antioxidant in Fats and Oils, 0.02% Fat Content Limit, GRAS Status, JECFA ADI 0.7 mg/kg bw/day, and Dietary Exposure Assessment (2022) (2022) — regulatory
- EFSA Panel on Food Additives: Re-evaluation of tert-Butylhydroquinone (E319) as a Food Additive — ADI 0.7 mg/kg bw/day Confirmation, Dietary Exposure Across Age Groups, Rodent Forestomach Papilloma Species Specificity, and Continued E319 Authorization (EFSA Journal 2020;18(3):6042) (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 →