Body & Beauty / Compounds / Butylated hydroxyanisole (BHA)

Butylated hydroxyanisole (BHA) on your skin: a safety profile

Low risk

Causes skin irritation. Butylated hydroxyanisole (BHA) classified H315.

What is butylated hydroxyanisole (bha)?

The IUPAC name is 2-tert-butyl-4-methoxyphenol.

Also known as: 2-tert-butyl-4-methoxyphenol, Phenol, (1,1-dimethylethyl)-4-methoxy-, tert-Butyl-4-hydroxyanisole, 2(3)-tert-Butyl-4-hydroxyanisole.

IUPAC name: 2-tert-butyl-4-methoxyphenol
CAS number: 25013-16-5
Molecular formula: C11H16O2
Molecular weight: 180.24 g/mol
SMILES: CC(C)(C)C1=C(C=CC(=C1)OC)O
PubChem CID: 8456

Risk for people

Low risk

Causes skin irritation. Butylated hydroxyanisole (BHA) classified H315.

Regulatory consensus

9 regulatory and scientific bodies have classified Butylated hydroxyanisole (BHA). The classifications differ — that's the data.

Agency	Year	Classification	Notes
IARC	1986	Group 2B (possibly carcinogenic to humans)	IARC Monograph 40 (1986). BHA classified Group 2B based on sufficient evidence for carcinogenicity in animals (forestomach papillomas and carcinomas in rats and hamsters at high doses) and inadequate evidence in humans. The forestomach is a rodent-specific organ absent in humans, creating uncertainty about direct human relevance. However, BHA metabolites (particularly tert-butylhydroquinone, TBHQ) exhibit genotoxic activity in some in vitro assays. IARC maintained the 2B classification pending further evidence. BHA consists of a mixture of two isomers: 2-tert-BHA (approximately 10–15%) and 3-tert-BHA (approximately 85–90%); the 3-isomer is responsible for the forestomach carcinogenicity.
EPA CTX / NTP RoC	—	Reasonably Anticipated to be a Human Carcinogen
EPA CTX / IARC	—	Group 2B - Possibly carcinogenic to humans
EPA CTX / CalEPA	—	Known human carcinogen
EPA CTX / Genetox	—	Genotoxicity: positive (Ames: positive, 80 positive / 18 negative reports)
EPA CTX / Genetox	—	Genotoxicity: positive (Ames: positive, 80 positive / 18 negative reports)
EPA CTX / Skin-Eye	—	Skin Irritation: SkinIrr2 (score: high)
EPA CTX / Skin-Eye	—	Skin Sensitization: Category 1 (score: high)
EPA CTX / Skin-Eye	—	Skin Sensitization: Category 6.5B (Category 1) (score: moderate)

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 hydroxyanisole (bha)

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 hydroxyanisole (BHA):

Physical/mechanical pest control (IPM)
Trade-offs: More labor-intensive. May not be sufficient for severe infestations.

Relative cost: 1.2-2×
Vitamin E (tocopherols)
Relative cost: 1.2-2×
Rosemary extract (carnosic acid)
Relative cost: 1.2-2×

Frequently asked questions

Is butylated hydroxyanisole (bha) safe for you?

Causes skin irritation. Butylated hydroxyanisole (BHA) classified H315.

What products contain butylated hydroxyanisole (bha)?

Butylated hydroxyanisole (BHA) 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 hydroxyanisole (bha)?

Butylated hydroxyanisole (BHA) has been classified by 9 agencies including IARC, EPA CTX / NTP RoC, EPA CTX / IARC, EPA CTX / CalEPA, EPA CTX / Genetox, 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 hydroxyanisole (BHA) in the body app

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

Open in body View raw API data

Sources (3)

IARC Monographs Volume 40: Some Naturally Occurring and Synthetic Food Components — BHA Group 2B Evaluation (Possibly Carcinogenic to Humans) (1986) — regulatory
US FDA: Butylated Hydroxyanisole (BHA) — GRAS Status, ADI, and Food Additive Regulations (21 CFR 172.110) (2020) — regulatory
US National Toxicology Program (NTP): BHA — Report on Carcinogens (15th Edition) — Reasonably Anticipated to Be a Human Carcinogen (2021) — 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 →