Preservatives
TBHQ (tertiary butylhydroquinone)
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
- tbhq
- tertiary butylhydroquinone
Regulation
Regulatory status
- European Union Banned
- Japan Banned
- United Kingdom Banned
- Australia/NZ Restricted
Explainer
In plain language
TBHQ, short for tertiary butylhydroquinone, is a synthetic antioxidant preservative used to keep fats and oils from going rancid. By slowing oxidation it extends the shelf life of fried, processed, and packaged foods. It is petroleum-derived and used in very small amounts, often alongside related preservatives like BHA and BHT.
Assessment
Why it is flagged
TBHQ is permitted by the FDA at up to 0.02 percent of the oil or fat content in a food, and EFSA has reviewed it and set an acceptable daily intake, so it remains legal in the US, EU, and other markets. The concern comes mainly from animal studies, where high doses have been associated with stomach lesions and effects on the immune system, and from its chemical family: the closely related preservative BHA is listed by IARC as possibly carcinogenic to humans (Group 2B), which shapes how the whole group is viewed. TBHQ itself has not been classified as a carcinogen by IARC, and human evidence at normal dietary levels is limited. Clear Label flags it because it sits in a preservative family with unresolved safety questions and because it marks heavily processed, fried, and long-shelf-life foods. This is a transparency flag and a pattern to watch in your own logs, not a demonstrated harm at typical intakes.
In the aisle
Where it commonly shows up
- Packaged fried snacks and chips
- Instant noodles and ramen
- Crackers and cookies
- Frozen and fast-food fried items
- Microwave popcorn
- Shelf-stable baked goods
- Some vegetable oils and shortenings
Practical
Reading the label
TBHQ is usually listed by name or as tertiary butylhydroquinone, often near the end of the ingredient list and sometimes noted as added to preserve freshness. It frequently appears in the frying oil of a product rather than the main recipe, so it can show up in foods you would not expect.
Alternatives
If you want to avoid it
Some people choose snacks preserved with vitamin E (tocopherols) or rosemary extract, or foods with shorter ingredient lists and shorter shelf lives. Fresh or home-fried versions of the same snack sidestep the preservative entirely.
FAQ
Common questions
Is TBHQ banned anywhere?
No major market bans TBHQ as of 2026. The FDA and EFSA both permit it within defined limits, with the FDA capping it at 0.02 percent of a food's fat and oil content.
Is TBHQ a carcinogen?
TBHQ has not been classified as a carcinogen by IARC. The closely related preservative BHA is in IARC Group 2B, possibly carcinogenic, which is part of why the wider family draws scrutiny.
Why is it flagged as high severity here?
It belongs to a preservative family with unresolved safety questions from animal studies and reliably marks fried, long-shelf-life, ultra-processed foods. Clear Label surfaces it so you can see how often it appears and test any personal patterns in your logs.
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.