Some chemicals used in personal care products have been linked to adverse health effects, prompting consumers to look for labels such as “free of phthalates,” “fragrance-free,” or “nontoxic.”
But a new analysis of 113 personal care and cleaning products found phthalates in several products labeled “phthalate-free,” along with other chemicals that contradicted their label claims (Environ. Health 2026, DOI: 10.1021/envhealth.6c00181).
The study was inspired by a trial done by the company Million Marker, which used at-home tests to measure exposure to endocrine-disrupting chemicals. Some participants in that trial changed products based on the company’s recommendations, but follow-up tests showed that markers of exposure to some of the chemicals had not decreased. That led the team at Million Marker Research Institute (a separate, nonprofit entity) to go “down the whole rabbit hole” of testing finished products directly, says Jenna Hua, an environmental health scientist at the institute and the study’s senior author, as well as the founder and CEO of Million Marker.
“Kudos to the researchers for pursuing this further,” Susan Richardson, a chemist at the University of South Carolina who was not involved in the study, says in an email. “This is quite the detective story.”
The researchers tested products across 12 categories, including shampoo, hair styling products, and sunscreen. They used nontargeted analysis with high-resolution 2D gas chromatography/mass spectrometry, a technique that looks broadly for chemicals rather than starting with a predetermined list. It identified 3,141 signals indicating chemical features, but the researchers could pick out only 303 chemicals with confirmed, probable, or tentative identities. This gap is typical, Richardson says. A single chemical can generate several signals, while other signals may come from noise or chemicals that aren’t in spectral libraries. “It is not easy to identify new chemicals,” she says.
Once identified, these chemicals were compared with the product labels. About 98% of the products contained at least one chemical that wasn’t listed. Among the unlabeled chemicals were familiar names such as parabens and oxybenzone, along with silicone contaminants D5 and D6. “It is concerning that 85% of the products tested had detectable levels of at least one compound known or suspected to be hazardous,” says Deborah Bennett, an exposure scientist at the University of California, Davis, who was not involved in the study. She says that is particularly troubling for lotions, moisturizers, and sunscreens, whose ingredients can remain on the skin for hours.
While earlier work has found similar contradictions between product labels and their chemical contents, “this study is much more comprehensive in the number of products they tested and in the characterization of chemicals using a more omics approach,” says Heather Stapleton, an environmental chemist at Duke University who was not involved in the work.
The researchers could not determine whether individual unlabeled chemicals were deliberately added or introduced unintentionally. Kim Schultz, a scientist at Million Marker Research Institute and the study’s first author, says manufacturers may not know what gets into their products as they move through the supply chain. “They’re all trying to do good, especially the small brands—they just don’t have control over their supply chain.” Tracey Woodruff, an environmental health researcher at the University of California, San Francisco, who was not involved in the study, says chemicals can enter during processing, leach from packaging, or form through degradation.
Hua says the team hopes to expand finished-product testing and eventually develop a certification program based on those tests. “If you don’t test, if you don’t know, there’s no way you’re going to address [unlabeled contamination],” she says.
