BHA and BHT (butylated hydroxyanisole and toluene)
BHA (E320) and BHT (E321) are synthetic phenolic antioxidants added to fats and fat-containing foods to slow oxidation and rancidity. Both are permitted by the FDA, EFSA, and JECFA at defined intake limits. BHA is classified by the IARC as Group 2B — possibly carcinogenic to humans — based on rodent forestomach tumours; BHT is IARC Group 3 (not classifiable). Both are NOVA Group 4 cosmetic-additive markers.
What are BHA and BHT?
BHA (butylated hydroxyanisole) and BHT (butylated hydroxytoluene) are synthetic phenolic antioxidants developed in the 1940s to prevent oxidation of fats. They interrupt the free-radical chain reactions that cause fats to go rancid, extending the shelf life of oils, cereals, snack foods, and cured meats. BHA carries E-number E320; BHT is E321.
Both are lipophilic — they dissolve in fats, not water — which is why they end up in oil-containing rather than aqueous products.
Regulatory position
- FDA: GRAS (generally recognised as safe) under 21 CFR 172.115 and 172.615 at defined limits.
- EFSA: last full re-evaluation 2011–2012; ADI 1.0 mg/kg body weight for BHA, 0.25 mg/kg for BHT.
- JECFA: same ADIs adopted by the WHO/FAO expert committee.
- IARC: BHA classified Group 2B (2018); BHT Group 3.
What the evidence base looks like
The IARC 2B classification of BHA rests on consistent evidence that high oral doses cause forestomach papillomas and carcinomas in rats and hamsters. The relevance to humans is contested because humans lack a forestomach and the metabolic pathway that produces the reactive intermediate in that tissue. Long-term human epidemiology is limited by low absolute exposure and difficulty separating BHA/BHT intake from broader ultra-processed dietary patterns.
BHT has a smaller adverse-outcome signal in rodent studies and no compelling human evidence.
Where they appear on labels
- Breakfast cereals — historically common, largely reformulated out in the US and UK since 2015.
- Instant potato products, dehydrated soup mixes.
- Fatty snacks — cheese-coated puffs, savoury crackers, tortilla chips.
- Chewing gum bases.
- Beef jerky and shelf-stable cured meats.
- Sausage casings and lard-based baked goods.
- Vegetable oils sold with extended shelf life for food service.
- Pet food (very common).
On labels look for "BHA", "BHT", "butylated hydroxyanisole", "butylated hydroxytoluene", or the E-numbers E320 and E321.
How NakedCalorie flags BHA and BHT
Both are Tier 2 additives with the IARC classification surfaced inline (2B for BHA; 3 for BHT). Presence of either moves the product to NOVA Group 4. See TBHQ for the closely related synthetic antioxidant, and sodium benzoate for the aqueous-food preservative equivalent.
Frequently asked questions
- Are BHA and BHT banned?
- No. Both are permitted in the US, EU, UK, Australia, and Japan at defined intake limits. The EFSA acceptable daily intake is 1.0 mg/kg body weight for BHA and 0.25 mg/kg for BHT. A few countries and several major manufacturers have voluntarily removed them from specific product lines under consumer pressure, not regulatory action.
- Why is BHA an IARC 2B substance if it's still allowed?
- IARC classifies hazard (does the substance have the potential to cause cancer at some exposure?), not risk (does the exposure people actually get cause cancer?). BHA caused forestomach tumours in rats at very high doses. Humans do not have a forestomach, and typical dietary exposure is orders of magnitude below the rodent no-effect level. Regulators evaluate risk and have concluded typical exposure is acceptable.
- Which foods contain them?
- Breakfast cereals, snack foods (especially cheese-coated crackers and puffs), instant potato products, chewing gum, lard-based baked goods, beef jerky, pet food, and cosmetic products. Manufacturers have widely reformulated cereals to remove BHT under retailer pressure in the past decade.
Written by NakedCalorie editorial team.
Medically reviewed by Pending registered dietitian review — last reviewed July 15, 2026.
Educational information only, based on peer-reviewed literature and regulatory sources. Not medical advice.
Related in the knowledge base
- AdditivesTBHQ (tert-butylhydroquinone)
- AdditivesSodium benzoate
- AdditivesPotassium sorbate