E321

BHT (Butylated Hydroxytoluene)

Last reviewed: 11 May 2026

The UK label-reader's guide to BHA's lower-profile cousin in cereals, snacks and chewing gum

What it is

E321 is butylated hydroxytoluene (BHT), a synthetic phenolic antioxidant manufactured from p-cresol and isobutylene. Like BHA (E320) and TBHQ (E319) it suppresses the free-radical chain reaction that turns fats and oils rancid, by donating a hydrogen atom to quench peroxyl radicals. BHT is cheap, effective at low concentration, and heat-stable enough to survive baking. It is frequently used in combination with E320 (BHA), where the two have a mildly synergistic effect; it is also used on its own.

Where you'll see E321 on a UK label

BHT is concentrated in dry processed foods where added vegetable fat or vitamin fortification needs to be protected from oxidation:

• Breakfast cereals, especially those fortified with added vitamins
• Cereal bars, granola, muesli bars
• Crisps, savoury fried snacks
• Crackers and biscuits, particularly long-shelf-life lines
• Chewing gum (in the gum base)
• Some processed meats — sausages, dry-cured meat snacks
• Vegetable cooking oils and shortenings
• Instant noodles, soup mixes and dehydrated sauces
• Some packaged nuts and seed mixes (to prevent rancidity of oil)

BHT is also commonly used in food-contact packaging — the antioxidant is incorporated into the plastic to protect the food's fat from migrating oxidants — and outside food in cosmetics and pharmaceuticals.

What the science shows

Liver and lung effects in animal studies

Long-term rodent studies have reported dose-dependent liver enlargement and altered liver enzyme activity at higher BHT doses, with the effects generally appearing well above realistic dietary intake. Some mouse studies have reported lung effects; the same model has also shown a protective effect of BHT against certain chemically-induced lung tumours, which is part of why the cancer literature on BHT is unsettled. EFSA's 2012 re-evaluation considered the available carcinogenicity dataset and concluded that the evidence does not support classifying BHT as a carcinogen — distinct from BHA (E320), which carries IARC Group 2B and US NTP listings.

The restrictive ADI

The EFSA Acceptable Daily Intake of 0.25mg/kg body weight per day is one of the lower antioxidant ADIs on the food-additive list and is set on the rat liver-enlargement endpoint with a substantial uncertainty factor. Realistic dietary intake from UK food is typically well below the ADI, but high consumers of fortified cereals and packaged snacks can approach a meaningful fraction of it.

Allergic and contact reactions

BHT is a recognised but uncommon contact allergen in cosmetics and food-contact materials. Reported reactions are predominantly dermatological — rashes, hives, contact dermatitis — and concentrated in people with broader sensitivity to phenolic antioxidants.

Regulatory status

UK / EU: approved as an antioxidant under Regulation (EC) No 1333/2008 with an EFSA Acceptable Daily Intake of 0.25mg/kg body weight per day (EFSA 2012 re-evaluation). Permitted in specific food categories at maximum levels of 100–400mg/kg of the fat fraction. Not permitted in foods for infants and young children.

US: FDA classifies BHT as Generally Recognised As Safe (GRAS) for use as a food antioxidant.

Japan: banned in food.

Australia / New Zealand: permitted with food-category-specific limits.

Reading a UK label

Look for "E321", "BHT", or "butylated hydroxytoluene" in the ingredients list, typically inside a fat or oil ingredient — for example "vegetable oil (with antioxidant: E321)". On UK cereal and snack packs it often appears alongside E320 (BHA) in the same fat blend, and on fried-snack and instant-noodle packs alongside E319 (TBHQ). Products that have moved to non-synthetic antioxidants typically list tocopherols (E306–E309 / vitamin E), rosemary extract (E392), ascorbyl palmitate (E304) or ascorbic acid (E300) instead. UK food for infants and young children does not contain E321.

Last updated: 11 May 2026