BHA and BHT are synthetic antioxidants added to food, cosmetics, and packaging to keep fats and oils from going rancid. Their full chemical names are butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). You’ll find them on ingredient labels of everything from breakfast cereal to potato chips to lipstick. They’ve been used commercially since the mid-20th century, and while they’re still approved for use in the U.S. and Europe, their safety profile has drawn increasing scrutiny.
How BHA and BHT Work
When fats and oils are exposed to oxygen, they break down through a chain reaction that produces unstable molecules called free radicals. This is what makes butter smell off or cooking oil taste stale. BHA and BHT interrupt that chain reaction by trapping free radicals before they can damage surrounding fat molecules. The result is food that stays fresh longer on the shelf, packaging that doesn’t degrade, and cosmetics that maintain their texture and color over time.
Both compounds are cheap to produce, effective at very low concentrations, and stable under heat, which is why they became the food industry’s go-to preservatives for anything with a significant fat content.
Where You’ll Find Them
BHA and BHT show up in a wide range of products. In food, they’re commonly added to frozen meals, breakfast cereals, cookies, candy, ice cream, meat products, potato chips, chewing gum, and vegetable oils. The FDA limits how much can be used: dry breakfast cereals, for example, can contain no more than 50 parts per million of BHT (alone or combined with BHA), while emulsion stabilizers for shortenings are allowed up to 200 parts per million.
Outside of food, both compounds appear in cosmetics (especially lipsticks and moisturizers, where they prevent oils from breaking down), pharmaceuticals, rubber products, and petroleum products. If you’ve ever noticed “BHT added to packaging material to preserve freshness” on a cereal box, that’s BHT in the plastic liner slowly releasing into the product to slow fat oxidation.
A Note on BHA in Skincare
This trips people up: BHA in skincare is not the same thing as BHA the food preservative. In the cosmetics world, “BHA” almost always refers to salicylic acid, a skin-exfoliating acid used to treat acne. Chemists will tell you salicylic acid isn’t technically a beta hydroxy acid at all, but the beauty industry adopted the term anyway. If you’re reading an ingredient list on a cleanser or serum and see “BHA,” that’s salicylic acid. If you see “butylated hydroxyanisole,” that’s the preservative.
Cancer Concerns With BHA
BHA carries a more concerning safety profile than BHT. The U.S. National Toxicology Program classifies BHA as “reasonably anticipated to be a human carcinogen,” based on animal studies showing it causes both benign and malignant tumors in the forestomach of rats, mice, and hamsters. A separate study found that exposing fish larvae to BHA in their diet led to liver cancer in adulthood.
The forestomach finding is significant but also a source of debate: humans don’t have a forestomach, which is a structure found in rodents. Some scientists argue this makes the rodent data less relevant to people. Others point out that the mechanism of damage (chronic irritation leading to abnormal cell growth) could plausibly occur in other tissues. The FDA announced in early 2025 that it is launching a formal reassessment of BHA’s safety as a food additive.
BHT has not received the same carcinogen classification. Some animal studies have actually shown BHT to have protective effects against certain cancers at low doses, though high doses can cause liver enlargement in rodents. The overall evidence is more mixed and less alarming than for BHA.
Hormonal Effects
BHA has also raised flags as a potential hormone disruptor. Multiple lab studies have found that BHA can mimic estrogen at a weak level, binding to estrogen receptors and stimulating the growth of human breast cancer cells in a dish. One study measured BHA’s estrogenic potency at roughly a million times weaker than the body’s natural estrogen, so the effect is not remotely comparable to actual hormones. But when combined with the body’s own estrogen, the effects appeared to be additive rather than competing, meaning BHA may slightly amplify existing estrogenic activity rather than cancel it out.
Lab studies also suggest BHA has some anti-androgenic properties, meaning it could potentially interfere with male hormones. These findings come from cell and receptor studies, not from human trials, so the real-world significance at the tiny doses found in food remains unclear.
How Much Is Considered Safe
International health bodies have set acceptable daily intake levels for both compounds. For BHA, the European Food Safety Authority (EFSA) sets the limit at 1 milligram per kilogram of body weight per day. The Joint FAO/WHO Expert Committee on Food Additives uses a stricter limit of 0.5 mg per kilogram of body weight per day, based on the dose at which precancerous changes appeared in rat forestomachs.
For a 150-pound (68 kg) person, the EFSA limit translates to about 68 milligrams of BHA per day. Given that food concentrations are measured in parts per million, you’d need to eat a large amount of preserved food daily to approach that threshold. Most dietary exposure estimates put typical intake well below the limit, though people who eat heavily processed diets obviously consume more.
In the European Union, BHT is authorized in food up to 400 mg per kilogram of the food product itself, and in animal feed up to 150 mg per kilogram of complete feed.
Natural Alternatives Gaining Ground
Growing consumer wariness has pushed many food manufacturers to swap BHA and BHT for natural antioxidants. The most common replacements are tocopherols (forms of vitamin E), rosemary extract, and various plant-derived compounds. Clove extract, for instance, has been shown to match BHT’s performance in preventing fat oxidation and color changes in beef patties during refrigerated storage. Rosemary extract performs similarly in sausage products.
You’ll increasingly see “tocopherols added to preserve freshness” or “rosemary extract” on labels where BHT or BHA once appeared, particularly in products marketed as natural or organic. These alternatives tend to cost more and may not perform as well under every condition, which is why BHA and BHT remain in wide use across the broader food supply.
How to Check Your Own Exposure
If you want to reduce your intake, the simplest approach is reading ingredient labels. BHA and BHT must be listed by name on food packaging in the U.S. and EU. They’re most likely to appear in shelf-stable snack foods, cereals, and anything with a long shelf life that contains fats or oils. Choosing products labeled “no artificial preservatives” or opting for fresh, minimally processed foods will lower your exposure significantly. Organic-certified foods in the U.S. do not permit synthetic preservatives like BHA or BHT.