TBHQ (tert-Butylhydroquinone)
Last reviewed October 18, 2026 · Evidence strength: Very limited · How we grade evidence
In plain words: TBHQ is an antioxidant that keeps frying oils and snack foods from going rancid. Lab and animal studies have raised immune-system questions, but no studies in people show harm at the small amounts allowed. It mostly shows up in fried and heavily processed foods, which is a better reason to eat less of them.
Also listed on labels as: TBHQ, tert-Butylhydroquinone, tertiary butylhydroquinone, E319
What is it, and why is it in food?
TBHQ is a synthetic antioxidant. US rules cap it at 0.02% of a food's fat. It's in frying oils, crackers, frozen fried foods, candy and snack cakes.
What does the science say?
| The popular claim | "TBHQ harms the immune system and may cause cancer." (Popularized by the advocacy group EWG; none of the five experts we reviewed named it.) |
| Our verdict on that claim | Not supported |
| Evidence strength | Very limited: lab screening and animal data only; no human studies. |
| Kinds of studies | Lab screening (EPA ToxCast), animal studies, reviews |
- Immune system: A 2021 study by EWG scientists found TBHQ active in EPA lab screening tests and animal immune studies, suggesting it "may" affect immune response in people. That's a hypothesis, not human evidence.1
- Cancer: A review describes TBHQ as protective against cancer in many studies (it switches on the body's antioxidant defenses), but possibly cancer-promoting with chronic high doses in animals.2
What do regulators say?
- FDA: approved, up to 0.02% of the oil or fat.3
- EFSA: safe daily limit of 0.7 mg per kg of body weight; realistic intakes stay below it.4
Who should be careful?
- No group has shown harm. Families who eat a lot of fried fast food and packaged snacks get the most.
How common is it in US foods?
In our check of USDA's Branded Foods database, 7,129 of 438,129 US packaged foods with an ingredient list name TBHQ (about 1.6%, or roughly 1 in 61).5 It shows up most often in: candy (747); cakes, cupcakes, snack cakes (692); cookies & biscuits (674); popcorn, peanuts, seeds & related snacks (509); crackers & biscotti (479). These are label records companies sent to USDA, mostly in 2021 to 2023, so some products have changed since. Counts come from a text match of ingredient lists and are approximate.
Swaps and tips for families
- Cook fried favorites at home in fresh oil, or bake them.
- Compare crackers and snack brands; many use vitamin E (tocopherols) or none.
Beyond the plate: related non-food exposures
TBHQ is also used in some cosmetics, varnishes and biodiesel. No consumer exposure concern identified.
Frequently asked questions
Is TBHQ bad for you?
There's no human evidence of harm at the tiny amounts allowed. Lab studies raised immune questions that haven't been tested in people.
Is TBHQ banned in Europe?
No. It's allowed in the EU as E319 with a safe daily limit.
What foods contain TBHQ?
Frying oils, fast-food fries and nuggets, crackers, candy and snack cakes.
Related guides
- BHA (Butylated Hydroxyanisole)
- BHT (Butylated Hydroxytoluene)
- Propyl Gallate
- Preservatives and acids
Sources
Every source below was checked against PubMed, the publisher or the official page by our research team in October 2026.
- Investigating Molecular Mechanisms of Immunotoxicity and the Utility of ToxCast for Immunotoxicity Screening of Chemicals Added to Food. International journal of environmental research and public health, 2021. PubMed 33804855 · doi:10.3390/ijerph18073332
- Chemoprotective and carcinogenic effects of tert-butylhydroquinone and its metabolites. Current drug metabolism, 2007. PubMed 17266519 · doi:10.2174/138920007779315035
- 21 CFR 172.185 TBHQ. Link
- Opinion of the Scientific Panel on food additives, flavourings, processing aids and materials in contact with food (AFC) on a request from the Commission related to tertiary-Butylhydroquinone (TBHQ). EFSA Journal, 2004. doi:10.2903/j.efsa.2004.84
- FoodData Central, Branded Foods dataset (release 2026-04-30). U.S. Department of Agriculture, Agricultural Research Service, 2026. Link
This guide is for general education. It is not medical advice and does not replace advice from your doctor, pediatrician, allergist or registered dietitian. If you think you or your child reacted to a food, talk to a health professional. Research changes; we review these pages when new evidence or rules come out. Last reviewed October 18, 2026. Spotted an error? Email [email protected].