BHT (butylated hydroxytoluene)

  • Our verdict: 4 - we recommend avoiding
  • Latest update & fact check: 9.7.2024 - Rebecca Taylor, CNP
  • Origin: It is produced synthetically and does not come from natural sources.

Butylated Hydroxytoluene (BHT), also known as E321, is a synthetic antioxidant widely used in the food and cosmetic industries. Its chemical structure consists of a toluene ring with two tertiary butyl groups and one hydroxyl group. BHT is a white crystalline solid, insoluble in water but soluble in organic solvents like ethanol and fats. It is valued for its ability to prevent oxidation, thereby extending the shelf life of products.


BHT is of artificial origin and is synthesized through chemical processes involving the reaction of p‑cresol with isobutylene in the presence of an acid catalyst. This synthetic production ensures consistency and purity, making BHT a reliable additive for various industrial applications.


BHT is used in food and other products for several key reasons:

  • Antioxidant Properties: Prevents the oxidation of fats and oils, which can lead to rancidity and spoilage.
  • Shelf Life Extension: Helps maintain product quality over longer periods by protecting against oxidative degradation.
  • Stabilization: Preserves the colour, flavour, and nutritional value of food products by inhibiting oxidation.
  • Compatibility: Works well in a variety of formulations due to its solubility in fats and oils.

Uses in Ultra‑Processed Foods

BHT is commonly used in ultra‑processed foods due to its potent antioxidant properties, providing several benefits:

  • Preservation of Oils and Fats: Used in products like snack foods, baked goods, and margarine to prevent rancidity. This maintains the flavour and safety of the food by protecting the fats from oxidative damage.
  • Colour Preservation: Helps in maintaining the vibrant colour of foods by preventing oxidative browning. This is particularly important in products like cereals and snack foods, where visual appeal is crucial.
  • Flavour Protection: Prevents the off‑flavours that can develop when fats oxidize, ensuring that the product tastes fresh for a longer time.
  • Nutrient Stability: Protects sensitive vitamins and nutrients from oxidative degradation, thus maintaining the nutritional quality of fortified foods and dietary supplements.

Health Considerations

While BHT is generally recognized as safe (GRAS) by the FDA and approved for use by the European Food Safety Authority (EFSA), there are some health considerations to keep in mind:

  • Potential Risks: High doses of BHT have been associated with adverse effects in animal studies, including liver enlargement and enzyme activity alterations. However, these effects are not typically seen at the levels used in food.
  • Allergic Reactions: Some individuals may experience allergic reactions to BHT, including skin rashes and respiratory issues.
  • Carcinogenicity Concerns: There is ongoing debate about the potential carcinogenic effects of BHT. Some animal studies have suggested a link between high doses and cancer development, but the evidence is not conclusive.
  • Endocrine Disruption: BHT has been shown to have endocrine‑disrupting effects in some studies, potentially affecting hormone function.
  • Bioaccumulation: Concerns about BHA's potential to accumulate in human tissues and its long‑term effects are still under investigation.


  1. Food and Drug Administration (FDA). "Food Additive Status List." FDA, www.fda.gov.
  2. European Food Safety Authority (EFSA). "Scientific Opinion on the Re‑evaluation of Butylated Hydroxytoluene (BHT) as a Food Additive." EFSA Journal, vol. 10, no. 3, 2012, pp. 2588‑2618.
  3. National Center for Biotechnology Information. "PubChem Compound Summary for CID 31404, Butylated Hydroxytoluene." PubChem, pubchem.ncbi.nlm.nih.gov.
  4. Kahl, R., and Kappus, H. "Toxicology of Synthetic Antioxidants BHA and BHT in Comparison with the Natural Antioxidant Vitamin E." Zeitschrift für Lebensmittel‑Untersuchung und -Forschung, vol. 196, no. 4, 1993, pp. 329‑338.
  5. Abdelgawad, Ahmed, et al. "Antioxidants: An Overview on the Natural and Synthetic Types." ResearchGate, 2017, www.researchgate.net/profile/Ahmed_Abdelgawad3/publication/321844679_Antioxidants_An_Overview_on_the_Natural_and_Synthetic_Types/links/64283b4492cfd54f84470e5e/Antioxidants‑An‑Overview‑on‑the‑Natural‑and‑Synthetic‑Types.pdf.