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E321AntioxidantElevated concern
Butylated Hydroxytoluene
In plain words
The short version
A synthetic phenolic antioxidant (BHT), the close relative of BHA, used to prevent rancidity in fats and packaged foods.
Why we flag it
A synthetic antioxidant that keeps fats from going rancid. Animal studies raised questions about its safety at high doses, and its effects are still debated at food levels. That's why we flag it.
Safety profile
ADI of 0.25 mg/kg body weight. Animal studies have raised concerns about endocrine and hepatic effects at high doses; human relevance debated. Some studies suggest anti-tumor activity, others suggest tumor-promoting. Several jurisdictions are progressively reducing permitted uses.
The detail
Developed in the 1940s alongside BHA as a synthetic antioxidant for petroleum products. Adapted for food and feed use in the 1950s. Produced from p-cresol and isobutylene.
Used in cereals, snack foods, chewing gum, animal fats, and packaging materials in contact with food. Often combined with BHA (E320) and citric acid for synergistic antioxidant effect. Typical use 0.001–0.02%.
White crystalline solid, soluble in fats and oils, insoluble in water. Volatile at elevated temperatures — can sublime from packaging into food.
Permitted in the EU and US with restricted maximum levels. Banned for certain uses in Japan and Australia.
Sources
- EFSA — Scientific Opinion on the re-evaluation of butylated hydroxytoluene BHT (E 321) as a food additive (2012) — European Food Safety Authority (EFSA), ANS Panel, 2012. ADI of 0.25 mg/kg bw
- WHO JECFA database — Butylated hydroxytoluene (INS 321), ADI 0–0.3 mg/kg bw (1995) — Joint FAO/WHO Expert Committee on Food Additives (JECFA), WHO, 1995. International safety evaluation (ADI 0–0.3 mg/kg bw)
- Commission Regulation (EU) No 1129/2011 establishing the Union list of food additives (Annex II to Regulation 1333/2008) — European Union, Official Journal L 295, 12.11.2011, 2011. Permitted in the EU with restricted maximum levels
- 21 CFR 172.115 — BHT (CFR, 2025 edition) — U.S. Government Publishing Office / FDA, 2025. Permitted in the US with restricted maximum levels
Checked against these sources on .
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