E320

BHA (Butylated Hydroxyanisole)

Last reviewed: 11 May 2026

The UK label-reader's guide to a synthetic antioxidant with two formal carcinogen classifications

What it is

E320 is butylated hydroxyanisole (BHA), a synthetic phenolic antioxidant manufactured from p-cresol and isobutylene. It works in the same way as the other synthetic phenolic antioxidants — by donating a hydrogen atom to quench peroxyl radicals in oxidising fats, halting the chain reaction that produces rancidity. BHA is cheap, very effective at low concentration, and heat-stable enough to survive baking and frying. It is frequently used in combination with E321 (BHT) because the two have a mildly synergistic effect.

Where you'll see E320 on a UK label

Use is concentrated in fat-containing processed foods where extended shelf life matters:

• Breakfast cereals, particularly those with nuts or added vegetable fat
• Cereal bars and granola
• Crisps and savoury fried snacks
• Crackers and biscuits
• Instant noodles
• Soup mixes and gravy granules
• Some cured meats — sausages, dry-cured meat snacks
• Chewing gum base
• Vegetable cooking oils and shortenings

It also turns up in non-food uses — cosmetics, pharmaceuticals (as a tablet excipient), packaging materials, and animal feed — which sit outside the EFSA food ADI.

What the science shows

IARC Group 2B classification

The IARC Monographs Working Group classified BHA as Group 2B — "possibly carcinogenic to humans" (Monograph 40, 1986; supplement 1987). The classification was based on sufficient evidence of carcinogenicity in experimental animals and inadequate evidence in humans at the time of evaluation. The animal data centred on dose-dependent forestomach tumours in rats and hamsters fed BHA at percentage-of-diet concentrations over long-term studies; tumour incidence rose with dose and was supported by precursor papillomas and hyperplastic lesions. IARC has not re-evaluated BHA since.

US NTP listing

The US National Toxicology Program lists BHA in its Report on Carcinogens as "reasonably anticipated to be a human carcinogen" on the basis of the rodent forestomach tumour data. The NTP review notes that humans lack the forestomach as a distinct anatomical structure, which has been used as one argument for limited relevance to humans — but the listing reflects the consistency and dose-response of the animal data and the absence of an established mechanism that could be confidently described as rodent-specific.

Endocrine and thyroid effects

BHA has shown thyroid hormone disruption in rodent studies and weakly oestrogenic activity in some in-vitro screens. The relevance of these signals to humans at realistic dietary exposure is contested in the published literature.

Regulatory status

UK / EU: approved as an antioxidant under Regulation (EC) No 1333/2008 with an EFSA Acceptable Daily Intake of 1mg/kg body weight per day (EFSA 2011 re-evaluation). Permitted at maximum levels of 100–400mg/kg of the fat fraction, depending on food category. Banned in foods for infants and young children under Regulation (EU) No 1129/2011 — a specific exclusion that reflects the regulator's caution.

US: FDA-permitted as Generally Recognised As Safe for use as an antioxidant in foods at limited levels, despite the NTP listing — a regulatory inconsistency that has drawn ongoing criticism from US public-health groups.

Japan: banned in food.

Reading a UK label

Look for "E320", "BHA", or "butylated hydroxyanisole" in the ingredients list, typically inside a fat or oil ingredient — for example "vegetable oil (with antioxidants: E320, E321)". It is frequently paired with E321 (BHT) in the same fat blend, and on snack packs it often appears alongside E319 (TBHQ) in the frying oil. Products that have moved to non-synthetic antioxidants typically list tocopherols (E306–E309 / vitamin E), rosemary extract (E392) or ascorbyl palmitate (E304) instead. UK food for infants and young children does not contain E320 — that exclusion is set in EU and retained UK food law.

Last updated: 11 May 2026