Preservatives
BHT (butylated hydroxytoluene)
Definition
What it is
Preservative flagged as a possible carcinogen by IARC or multiple regulatory bodies. BHA is listed as a possible human carcinogen (Group 2B); BHT and TBHQ have related concerns.
On the label
How it appears on labels
- bht
- butylated hydroxytoluene
Regulation
Regulatory status
- European Union Banned
- Japan Banned
- United Kingdom Banned
- Australia/NZ Restricted
Explainer
In plain language
BHT, or butylated hydroxytoluene, is a synthetic antioxidant preservative used to stop fats and oils from spoiling. Like its close relative BHA, its main job is extending shelf life in foods that contain fat. It is manufactured industrially and often appears in the same products.
Assessment
Why it is flagged
BHT has raised safety questions in animal studies, where high doses have been associated with a range of effects, but the evidence is more mixed than for BHA. Unlike BHA, BHT is not classified by IARC as possibly carcinogenic, and some animal studies have even suggested protective antioxidant effects, which is part of why the science is unsettled. The FDA permits BHT as generally recognized as safe within limits, and EFSA set an acceptable daily intake after its review. Clear Label groups it with BHA at high severity because the two are chemically related and frequently used together, and because their long-term dietary effects remain debated. The honest summary is that BHT is less flagged than BHA by classification bodies but shares the same family of open questions.
In the aisle
Where it commonly shows up
- Breakfast cereals
- Chips and snack foods
- Chewing gum
- Shortening and vegetable oils
- Dehydrated potato products
- Some packaged baked goods
Practical
Reading the label
It shows up as BHT or butylated hydroxytoluene, often with the phrase 'added to preserve freshness'. It is sometimes used in the packaging liner rather than the food itself, in which case it may not appear on the ingredient list. In the EU it is E321.
Alternatives
If you want to avoid it
Some people choose products that use vitamin E (tocopherols) or rosemary extract as the antioxidant, or fresher foods that do not rely on long shelf lives. Cereals and snacks vary widely on this, so comparing labels is usually enough.
FAQ
Common questions
Is BHT more or less concerning than BHA?
IARC classifies BHA as possibly carcinogenic (Group 2B) but does not give BHT the same classification. The two are chemically related and often used together, which is why Clear Label flags both, but the specific evidence differs.
Is BHT banned anywhere?
BHT is broadly permitted as a food additive, including in the US and EU, within set limits. No major market has banned it as of 2026.
Why is the research called mixed?
Some animal studies associated high doses of BHT with adverse effects, while others suggested antioxidant benefits, and human dietary evidence is limited. That is why regulators permit it while the long-term picture stays debated.
Citations
Sources
Citation
Primary reference
About this page: the definition, label names, severity, and regulatory chips come from the clearlabel ingredient taxonomy, the same data the scanner uses to score products. Research summaries describe associations reported in published studies, not diagnoses; individual responses vary. Scan any product with clearlabel to see which of its ingredients carry flags.