E321 - Butylated hydroxytoluene

At a glance

• What it is: A synthetic antioxidant (phenolic compound) commonly called BHT
• E-number: E321
• What it does: Slows oxidation to keep fats and oils from going rancid
• Typical in: Fat- or oil-containing foods and snacks
• Dietary notes: Not derived from animals; suitable for vegetarian and vegan diets
• Also called: 2,6-di-tert-butyl-p-cresol; listed on labels as “butylated hydroxytoluene” or “BHT”

Why is Butylated hydroxytoluene added to food?

BHT is added because oxygen can break down fats and oils, creating off-flavors and stale or “paint-like” aromas. As an antioxidant, BHT donates electrons to reactive oxygen species, stabilizing them and slowing the chain reactions that cause rancidity.¹

In the United States, the Food and Drug Administration (FDA) permits BHT to be added to foods containing fats or oils, with a common upper limit of 0.02% of the fat or oil in the food.¹

What foods contain Butylated hydroxytoluene?

You’re most likely to find BHT in foods that contain fats or oils, because that’s where it can best slow oxidation. Typical categories include certain shelf-stable snacks and other packaged foods made with fat or oil; always check the ingredient list for “butylated hydroxytoluene,” “BHT,” or “E321.”¹ In the European Union (EU), BHT is authorized as food additive E321 and may be used only in specific foods and at levels laid down in law.²

BHT may also be used alongside other antioxidants, such as butylated hydroxyanisole (BHA) or propyl gallate, depending on the recipe and regulations.

What can replace Butylated hydroxytoluene?

Food makers that want to avoid BHT can choose other antioxidants, sometimes alone or in blends:

• Natural-source options like tocopherol-rich extract or alpha-tocopherol
• Ascorbic-acid-based options such as ascorbyl palmitate
• Plant extracts like extracts of rosemary
• Synergists that support antioxidants, for example citric acid
• Other approved synthetic antioxidants, e.g., butylated hydroxyanisole (BHA) or propyl gallate

Which replacement works best depends on the food’s fat type, flavor profile, processing, and storage.

How is Butylated hydroxytoluene made?

Commercially, BHT is produced by reacting p-cresol (4-methylphenol) with isobutylene to attach two tert‑butyl groups, yielding 2,6-di-tert‑butyl‑p‑cresol—the chemical name for BHT.³ The result is a stable phenolic antioxidant that dissolves well in fats and oils.

Is Butylated hydroxytoluene safe to eat?

Safety assessments and legal limits guide its use. In the U.S., FDA regulations authorize BHT as a food additive and set maximum use levels, typically up to 0.02% of the fat or oil in the food.¹ In the EU, BHT is listed as E321 and is authorized only for specified foods and conditions laid down in Regulation (EC) No 1333/2008.²

The European Food Safety Authority (EFSA) has re-evaluated BHT as part of its ongoing review of food additives, establishing an acceptable daily intake (ADI) and assessing exposure from foods.⁴ The EU also sets detailed purity criteria for BHT through a separate specification regulation.⁵ When manufacturers follow these rules, authorities consider BHT safe for its intended uses.

Does Butylated hydroxytoluene have any benefits?

• Helps keep flavors and aromas fresh by slowing fat oxidation
• Extends shelf life of fat-containing foods, which can help reduce food waste
• Can work in synergy with other antioxidants for broader protection

Who should avoid Butylated hydroxytoluene?

• People who prefer to avoid synthetic additives for personal or dietary reasons
• Anyone advised by a healthcare professional to limit phenolic antioxidants
• Shoppers following elimination diets may choose products labeled without synthetic antioxidants

If you are concerned, look for products labeled “no artificial preservatives” or check the ingredient list.

Myths & facts

• Myth: “BHT is banned in the EU.” Fact: BHT is authorized as E321 in the EU, with specific conditions and limits.²
• Myth: “Companies can add as much BHT as they want.” Fact: Both the U.S. and EU set strict maximum levels and specifications for its use.¹⁵
• Myth: “BHT and BHA are the same thing.” Fact: They are different antioxidants; BHT is E321 and BHA is E320, and each has its own rules and specifications.²

Butylated hydroxytoluene in branded foods

On ingredient lists, look for “butylated hydroxytoluene,” “BHT,” or “E321,” often followed by a short note such as “to preserve freshness.” It most often appears in products that contain fats or oils. If you want to avoid it, scan labels or choose products that use alternatives like tocopherols or extracts of rosemary.

References

Footnotes

1. 21 CFR 172.115 — Butylated hydroxytoluene. U.S. Food and Drug Administration (eCFR). https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-172/subpart-B/section-172.115 ↩ ↩² ↩³ ↩⁴ ↩⁵

2. Regulation (EC) No 1333/2008 on food additives. EUR-Lex (EU). https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32008R1333 ↩ ↩² ↩³ ↩⁴

3. Butylated Hydroxytoluene (BHT) — Compound Summary. PubChem, National Institutes of Health. https://pubchem.ncbi.nlm.nih.gov/compound/Butylated-hydroxytoluene ↩

4. Re-evaluation of butylated hydroxytoluene (E 321) as a food additive — Scientific Opinion. EFSA Journal. European Food Safety Authority. https://www.efsa.europa.eu/en/efsajournal/pub/2588 ↩

5. Commission Regulation (EU) No 231/2012 laying down specifications for food additives listed in Annexes II and III to Regulation (EC) No 1333/2008. EUR-Lex (EU). https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32012R0231 ↩ ↩²