E321 – Butylated hydroxytoluene (BHT)

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Published:

October 16, 2025

Last modification:

October 18, 2025

Safety grading ORANGE – SOME CONCERNS

E321 (butylated hydroxytoluene, BHT) is graded ORANGE — Some Concerns. EFSA’s 2012 re‑evaluation set an ADI of 0.25 mg/kg body weight per day based on multigeneration studies and a thresholded mode of action for tumor promotion. Typical adult intakes in Europe are generally below this ADI, but mechanistic literature reports liver enzyme induction, thyroid and reproductive effects, and tumor‑promotion activity at high doses in rodents. Human data are limited. Considering legal approval, usually low exposure, and persistent mechanistic concerns (and potential mixture effects with other phenolic antioxidants), we judge ORANGE to be the prudent classification.

Caveats and context: (1) Findings are often from high‑dose or long‑term animal studies. (2) Mixture and cumulative exposure scenarios remain uncertain. (3) Sensitive populations and heavy consumers of processed fats may wish to limit intake.

Should You Avoid E321?

Most consumers do not need to avoid BHT entirely. To reduce exposure, favor products formulated without phenolic antioxidants, choose fresh and minimally processed foods, and vary brands. Individuals with hormone‑sensitive conditions or a precautionary approach may select BHT‑free options.

Common Uses

Edible fats and oils, snacks, nuts, and fat‑rich bakery items.
Cereals and breakfast bars.
Dehydrated instant foods and soups.
Some processed meats and seasonings.

Common names / Synonyms

Butylated hydroxytoluene, BHT.
2,6‑di‑tert‑butyl‑4‑methylphenol.
Antioxidant E321.

What is it?

BHT is a synthetic phenolic antioxidant functioning as a chain‑breaking radical scavenger that interrupts lipid oxidation. Industrial manufacture typically involves alkylation of p‑cresol with isobutylene to introduce tert‑butyl groups, producing a lipophilic antioxidant that partitions into fat phases. After ingestion, BHT is absorbed and metabolized, with reported high‑dose effects in animals on hepatic enzymes, thyroid homeostasis, reproduction, and tumor promotion in sensitive models. At realistic dietary exposures, regulators conclude risks are acceptable within the ADI, but scientific debate persists.

Where it’s allowed (EU vs US)