Hidden hazards: Study finds cancer-linked chemicals in most hair extensions

• A new study found chemicals on hazard lists, including carcinogens and reproductive toxicants, in 91% of 44 tested hair extension products.
• Four synthetic products contained organotin plastic stabilizers at levels exceeding European Union safety limits, which leached into warm water.
• Products marketed as “non-toxic” or “phthalate-free” sometimes contradicted their own claims, though two products did test clean.
• The $14 billion industry has virtually no ingredient disclosure requirements, leaving consumers in the dark.
• Black women, who use extensions at seven times the rate of White women, bear a disproportionate potential exposure, raising serious health concerns.

In an industry projected to reach $14 billion globally by 2028, a groundbreaking new study reveals a troubling lack of transparency and safety. Research published in the journal Environment & Health has found that the vast majority of hair extensions—both synthetic and natural—contain chemicals flagged on authoritative hazard lists, including substances linked to cancer and reproductive harm. The findings spotlight a significant regulatory gap.

A chemical cocktail on the scalp

Scientists from the Silent Spring Institute and Southwest Research Institute purchased 43 popular hair extension products from beauty supply stores and online retailers, testing a range of synthetic fibers, natural human hair, and biobased alternatives like banana fiber. Using advanced chemical analysis, they detected 933 distinct chemical signatures across the samples. Alarmingly, 91% of the products contained at least one chemical appearing on California’s Proposition 65 list, which mandates warnings for carcinogens and reproductive toxicants.

The most concerning discovery involved organotin compounds, plastic stabilizers found in four synthetic products at concentrations that would violate European Union safety limits. Laboratory simulations showed these chemicals could leach into warm water, mimicking exposure during a shower. Studies in animals have linked certain organotins to metabolic problems and insulin resistance. Beyond tins, researchers found high levels of chlorine (indicating flame retardants) and fluorine (suggesting water-repellent treatments), alongside plasticizers associated with developmental issues.

“Non-toxic” claims often misleading

The marketplace offers little reliable guidance for consumers. While two products labeled “non-toxic” were among the cleanest tested, validating their claims, others made false assurances. Banana fiber extensions advertised as containing “no phthalates” actually contained them. So-called “virgin” human hair showed signs of chemical processing, and a sample of “raw” human hair contained pesticide residues. Unbranded products labeled simply as “synthetic hair” were frequently the worst offenders, containing the highest chemical loads. This pattern of unverified claims echoes long-standing issues in consumer product safety, where marketing often outpaces meaningful oversight.

A question of equity and cumulative exposure

The public health implications are compounded by stark demographic usage patterns. More than 70% of Black women in the U.S. wear hair extensions at least once a year, compared to less than 10% of White women. These products are often worn for weeks or months at a time, pressed against the scalp during sleep, showers, and heat styling, creating multiple pathways for chemical transfer through the skin, inhalation, and hand-to-mouth contact.

Navigating an unregulated landscape

For now, consumers navigate a marketplace with virtually no ingredient disclosure. The study authors note that over 80% of the chemical signatures they detected could not even be identified due to a lack of public data on industrial compounds. This information blackout prevents informed choice. Experts suggest seeking out brands that have undergone independent verification, being skeptical of vague “natural” or “non-toxic” claims, and minimizing heat styling of extensions to reduce fume inhalation.

Toward transparency and safety

The study concludes with a call for policy action, advocating for the same basic ingredient disclosure and hazardous chemical restrictions applied to many other consumer goods. Some movement is underway; California’s Proposition 65 has driven manufacturers to reformulate products to avoid warning labels. The research underscores that understanding the full health impact requires first knowing what is in these products—a basic right currently denied to millions of consumers. As the industry grows, the demand for transparency and safety is likely to follow, pushing regulators and manufacturers to close a gap that has left public health to chance.

Sources for this article include:

StudyFinds.org

ACS.org

ScientificAmerican.com