Scientists Warn Popular Hair Extensions Contain Cancer‑Linked Chemicals

Scientists Warn Popular Hair Extensions Contain Cancer‑Linked Chemicals

A new study has revealed that many popular hair extensions, including those made from human hair, contain chemicals linked to cancer, hormone disruption, and reproductive harm, raising serious health concerns for consumers worldwide. The findings, published in the American Chemical Society journal Environment & Health, represent the most comprehensive chemical analysis of this largely unregulated beauty product category to date.

Researchers from the Silent Spring Institute tested 43 hair extension products purchased from online retailers and local beauty supply stores. These included synthetic fibers and bio-based materials, such as human, banana, and silk hair. Using advanced non-targeted chemical analysis and high-resolution mass spectrometry, scientists detected over 900 chemical signatures, identifying 169 distinct chemicals. Most of the samples contained hazardous substances linked to cancer, hormone disruption, developmental harm, and immune system effects.

Among the dangerous compounds detected were phthalates, styrene, pesticides, flame retardants, tetrachloroethane, and organotins. Some chemicals, such as organotins, were found at levels exceeding European Union safety limits, while 17 chemicals identified in 36 products were linked to breast cancer and hormone disruption. Only two products tested were free of hazardous chemicals and labeled “non-toxic”.

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Lead author Dr. Elissia Franklin said the study highlights the disproportionate exposure risk faced by Black women, who use hair extensions at much higher rates than other demographic groups. Surveys show that more than 70 percent of Black women reported wearing extensions at least once in the past year, compared with fewer than 10 percent of women from other racial or ethnic groups. Franklin explained that extensions are often worn for cultural expression, personal style, and convenience, yet users are largely unaware of the health risks posed by prolonged chemical exposure.

Because hair extensions rest directly against the scalp and neck, wearers may experience extended skin contact, and heating during styling can release chemicals into the air, leading to inhalation exposure. The study also found that manufacturers rarely disclose the full list of chemicals used to make extensions flame-resistant, waterproof, or antimicrobial, leaving consumers in the dark about potential hazards.

Consumer advocates are calling for stricter regulation, mandatory ingredient disclosure, and safer product alternatives. With the global hair extension market projected to exceed $14 billion by 2028, experts warn that millions of users could face cumulative exposure to toxic chemicals unless companies and regulators take action.

Dr. Franklin concluded: “These findings make clear that stronger oversight is urgently needed to protect consumers and push companies to invest in making safer products. No one should have to choose between cultural expression, convenience, and their health.”