Benzophenone is not considered fully safe. It is classified as “possibly carcinogenic to humans” by the International Agency for Research on Cancer (IARC Group 2B), and the FDA banned it as a food additive in 2018 after evidence showed it causes cancer in laboratory animals. That said, the risks depend heavily on how you’re exposed and at what levels.
Why Benzophenone Was Banned in Food
Benzophenone was once permitted as a synthetic flavoring agent and as a plasticizer in rubber food-contact materials. In 2018, the FDA revoked both uses. The decision was triggered by the Delaney Clause, a provision of federal law that prohibits the FDA from approving any food additive found to cause cancer in humans or animals at any dose. Because animal studies showed benzophenone caused cancer, the FDA had no legal flexibility to keep it on the approved list, regardless of the dose levels involved.
California also lists benzophenone under Proposition 65 specifically for cancer risk, which is why you may see warning labels on certain products sold in the state.
What Animal Studies Found
The National Toxicology Program ran a two-year study exposing rats and mice to benzophenone and found evidence of carcinogenic activity in both species and both sexes. Male rats developed kidney tumors at higher rates, while male mice showed increased liver tumors. Female rats had marginally higher rates of leukemia, and female mice developed a rare cancer called histiocytic sarcoma more frequently than unexposed animals. The evidence was characterized as “some” rather than “clear,” meaning it was real but not overwhelming. No human cancer data exists, which is why the IARC classification lands at “possibly” rather than “probably” carcinogenic.
Benzophenone in Food Packaging
Even though benzophenone is no longer added to food intentionally, it still shows up through packaging. Benzophenone is used as a photoinitiator in printing inks on cardboard and cartonboard, and it can migrate into the food inside. One study testing 71 packaged foods found benzophenone in 72% of them. Most contaminated samples fell in relatively low ranges, but a few were much higher. The worst case was a high-fat chocolate product stored at room temperature in direct contact with printed cardboard, which contained 7.3 mg per kilogram of food. Fatty foods absorb more benzophenone from packaging because the chemical is lipophilic, meaning it dissolves readily into fats and oils.
If you want to minimize this kind of exposure, transferring food out of printed cardboard packaging and into glass or ceramic containers helps, especially for fatty or oily products.
Benzophenone-3 and Sunscreen
The benzophenone family includes several derivatives, and the one most people encounter daily is benzophenone-3, commonly called oxybenzone. It’s one of the most widely used UV filters in sunscreens, lip balms, and cosmetics. Oxybenzone is lipophilic, photostable, and absorbs quickly through skin. Once inside the body, it gets metabolized into benzophenone-1, which actually has a longer biological half-life and stronger estrogen-mimicking activity than oxybenzone itself.
This matters because benzophenone-1 can interact with hormone receptors. Studies in fish exposed to oxybenzone at concentrations as low as 26 micrograms per liter showed significant drops in egg production and disruption of steroid hormone pathways. Testosterone levels spiked in males, the ratio of estrogen to testosterone shifted in both sexes, and genes involved in hormone production were broadly suppressed. These are aquatic studies at environmental concentrations, not direct proof of harm in humans, but they illustrate that the benzophenone family has real biological activity at low levels.
Skin Reactions
Beyond systemic concerns, benzophenone derivatives can cause contact allergies. Patch testing data from the North American Contact Dermatitis Group, covering nearly 20,000 patients between 2013 and 2020, found that about 2.1% of people tested positive for an allergic reaction to at least one form of benzophenone used in sunscreens. That’s not a huge percentage, but if you’ve noticed redness, itching, or a rash after applying sunscreen, benzophenone sensitivity is worth considering.
Environmental Concerns
Oxybenzone washes off swimmers and enters waterways, which has raised alarms about coral reef damage. Laboratory studies exposing the coral species Acropora tenuis to oxybenzone found that the concentration needed to kill half the coral was 3.9 mg per liter. That’s higher than what’s typically measured in ocean water near popular beaches, and the researchers concluded the immediate environmental risk to corals was low based on current exposure levels. However, oxybenzone is bioaccumulative, meaning it builds up over time in organisms and sediment. Hawaii and several other jurisdictions have banned oxybenzone-containing sunscreens as a precautionary measure.
How to Reduce Your Exposure
Your two main sources of benzophenone exposure are sunscreen and food packaging. For sunscreen, mineral alternatives based on zinc oxide or titanium dioxide provide UV protection without benzophenone derivatives. These sit on top of the skin rather than being absorbed into it. For food, avoiding prolonged storage of fatty foods in printed cardboard reduces migration. Choosing products in glass, metal, or unprinted packaging helps as well.
Benzophenone is not acutely dangerous at the trace levels most people encounter. The concern is cumulative, low-level exposure over years, particularly given the animal cancer data and the hormone-disrupting properties of its metabolites. The regulatory trend is clearly moving toward greater restriction: it’s already out of food, flagged under Prop 65, and increasingly replaced in sunscreen formulations sold in environmentally sensitive areas.