A new peer-reviewed study indicates that common personal care products frequently contain toxic chemicals not listed on their labels. Testing of over 110 items—including shampoos, baby lotions, moisturizers, and feminine hygiene products—revealed evidence of undisclosed toxicants in approximately 85 percent of samples.
Many products harbored multiple ingredients classified as carcinogens or health hazards. Notably, 26 percent of items marketed as “eco,” “green,” or “natural” contained at least one dangerous compound. On average, products contained more than three times the number of chemicals declared on their ingredient lists.
It remains unclear whether the contamination is intentional or accidental. Regardless, the findings intensify scrutiny over the safety of daily-use consumer goods and underscore the need for stricter regulatory oversight, including mandatory testing, according to the study authors.
Jenna Hua, a lead author affiliated with Million Marker—a San Francisco firm offering at-home toxic exposure testing—said researchers anticipated finding some undisclosed chemicals but were “shocked” by the extent of the problem.
“I spend my money, and I want to get a good product—why am I being lied to?” Hua asked.
Detected substances included hormone disruptors and carcinogens such as phthalates, parabens, PFAS, and formaldehyde. These chemicals, sometimes intentionally added to formulations, are linked to cancer, neurological disorders, reproductive harm, and developmental damage in children. Research over recent decades has confirmed that personal care product chemicals can be absorbed into the body.
The 113 products tested were purchased from major retailers including Target and Amazon. The sample spanned baby products, soaps, shampoos, toothpaste, body washes, cleaning products, and other everyday goods.
Undisclosed ingredients may stem from illegal addition, unintended chemical reactions between components, or leaching from plastic packaging, the authors noted. The most pervasive hidden toxicants fall under the generic label terms “fragrance” or “parfum,” which can encompass any of roughly 1,200 hazardous chemicals without requiring specific disclosure under current law.
The situation presents challenges for small businesses genuinely attempting to produce clean products. Some unknowingly source contaminated raw materials or are misled by suppliers. Hua said Million Marker has spoken with such companies that want to reformulate but fear predatory lawsuits over contamination they did not cause.
Stronger regulations could help well-intentioned producers avoid these pitfalls and create a level playing field.
“There needs to be some regulations and a testing component to ensure it’s safe,” Hua said, adding that Million Marker is actively fundraising to conduct further testing.
Researchers employed non-targeted chemical analysis, which screens for evidence of thousands of substances rather than a limited predetermined panel. The analysis identified 303 chemicals the authors were confident were present, though the actual number may be higher. These were cross-referenced against the Environmental Protection Agency’s database of hazardous chemicals.
Among the 26 percent of products contradicting their marketing claims, synthetic chemicals appeared in items labeled “100% natural”; phthalates were found in goods labeled “phthalate-free”; and known allergens appeared in products marketed as “hypoallergenic.”
“It’s very hard for the individual consumer to know what’s in the products, even if they are super-conscientious and reading the labels,” said Kristen Knox, a research scientist with the Silent Spring Institute, a public health nonprofit that has also tested personal care products but was not involved in this research. “Consumers don’t have access to a lab.”
Knox said the findings expose a fundamental flaw in the U.S. regulatory approach, which assumes chemicals are safe until evidence of harm emerges, rather than requiring safety testing beforehand. Previous Silent Spring research estimated that listed ingredients in personal care products release 5,000 tons of volatile organic compounds into U.S. homes annually, with many such products marketed heavily toward women of color.
In 2022, a public health group detected benzene—a highly carcinogenic chemical—in 27 percent of 663 products tested, including some at life-threatening levels. That discovery prompted major recalls by Procter & Gamble, Bayer, CVS, and others for brands including Old Spice and Pantene.
While there is no foolproof way to avoid undisclosed ingredients, certain steps can reduce exposure. Avoiding products listing “fragrance” or “parfum” is a primary measure. Products with less plastic packaging carry a lower risk of contamination from plasticizers such as BPA or phthalates. Choosing formulations with fewer, verifiably natural ingredients reduces the risk of unintended chemical reactions, though the study demonstrates this does not eliminate risk entirely.
A useful resource is the Environmental Working Group’s Skin Deep database, which rates ingredient lists for thousands of products, though it does not account for unlabeled contaminants. It can, however, support more informed decisions.
Hua advised that reducing the number of personal care products used and avoiding high-risk categories such as nail products are practical protective steps for consumers.