Hazardous chemicals go unlabeled in most personal care products

Clinical takeaway: When patients ask how to lower chemical exposures, reading ingredient lists and switching to "clean" brands may not get them far. Using fewer scented and leave-on products is a more reliable lever.

Counseling on chemical exposure usually ends at the label. Read the ingredient list, avoid the named offenders, choose the version marked free of them. It is the one concrete thing a clinician can hand a patient who wants to lower exposure without overhauling her life. 

That advice rests on an assumption worth examining: that what is printed on the package reflects what is inside it. Fragrance alone can shelter dozens of undisclosed compounds under trade-secret protection, and nothing on a label accounts for what arrives through raw materials or leaches from packaging. 

The patients who ask are often the ones with the most at stake, including women planning pregnancy and parents buying products for infants. Nontargeted chemical analysis of 113 personal care and cleaning products across 12 categories, purchased in 2021 and 2022 and reported by users of a consumer biomonitoring program, compared what labels listed against what testing found. 

Nearly all products, 106 of 113, contained at least one chemical absent from the label, and 85% contained at least one unlabeled chemical with a known or suspected hazard. Products averaged 51 detected chemicals against 16 listed ingredients. Fragrance compounds, plasticizers including phthalates, silicone contaminants, and butylated hydroxytoluene (BHT) accounted for most of the hazardous detections. 

The label ratings did not sort the products. Investigators had graded each item on its ingredient list alone before testing, and 59% of the 27 products rated best still failed on undisclosed contaminants. Overall, 57.5% failed, and failure rates ran between 50% and 60% across small, medium, and large brands. Oral care, the one category where every product passed, is also the one regulated largely as over-the-counter drugs rather than cosmetics. 

More than one-quarter of products, 29 of 113, contained chemicals that contradicted a stated claim. Synthetic compounds appeared in items sold as 100% natural, phthalates in products marketed phthalate-free, and allergens or sensitizers in products labeled hypoallergenic. Several items carrying third-party certifications or well-rated in consumer scoring apps failed testing. 

Testing used two-dimensional gas chromatography with high-resolution mass spectrometry and machine-learning-assisted identification, which screens for thousands of compounds without a predefined target list. Each product received a hazard score compiled from regulatory and toxicological databases including the EPA CompTox dashboard, plus a separate pass/fail rating based only on unlabeled chemicals present at 1 μg/g or higher. Products were chosen to span the range of label-based ratings, not to represent the market. The framework scores intrinsic chemical hazard, not dose, absorption, or exposure.

For ingredient lists to become a more usable tool, testing would have to move to the finished, packaged product. The Modernization of Cosmetics Regulation Act of 2022 (MoCRA) gave FDA its broadest cosmetics authority to date, covering facility registration, safety substantiation, adverse event reporting, and recalls. But the model stayed the same one that governs most consumer chemical oversight in the US: companies register, document, and report, and regulators act after a problem surfaces. Routine testing of what ships is still not required. Until that changes, the authors propose nontargeted screening as a routine addition to the stability and microbial testing already standard in the industry. Reports naming individual products are planned, which would give clinicians something more specific than a category to point to. 

Million Marker funded this study alongside the Taber Trust and individual donors, and the 113 products came from what its users reported using. It is a Berkeley, CA nonprofit that sells a mail-in urine test measuring endocrine-disrupting chemical metabolites and returns personalized advice on which products to swap.

"We found undisclosed harmful chemicals in products claiming to be free of them. That means someone can carefully read ingredient lists, choose 'clean' products, and still end up exposed to the very chemicals they were trying to avoid. The label can't protect you when it doesn't show what's really in the bottle," said Jenna Hua, PhD, MPH, senior author and founder of the Million Marker Research Institute. 

Source: Schultz K, et al. (2026 Aug 11) Environ Health. Hidden Hazards: Nontargeted Chemical Analysis Reveals Widespread Contaminants and Mislabeling in Personal Care and Cleaning Products