A new wave of lab testing has put hair extensions — the braiding hair millions of Black women and girls use for styles like box braids, twists, and faux locs — under the microscope, and the results are alarming. 

Independent researchers found dozens of potentially hazardous chemicals across both synthetic and so-called “natural” extensions, while follow-up testing by consumer groups detected heavy metals and volatile organic compounds (VOCs) in many popular products. The Environmental Working Group and a peer-reviewed paper led by the Silent Spring Institute describe a category of beauty products that, until now, has been largely unregulated. 

The Silent Spring study tested 43 extension samples — including synthetic fibers, untreated human hair, and biobased alternatives — and identified 169 distinct chemicals and 933 unique chemical signatures. At least one compound linked to cancer or reproductive harm showed up in 91% of samples. The researchers flagged substances such as phthalates, styrene, and other chemicals on California’s Proposition 65 list, which requires businesses to provide warnings on products with these chemicals present. “The hazardous chemicals we identified each carry their own risks,” the study’s lead author, Elissia T. Franklin, said, noting the concern that repeated, long-term scalp exposure can add up. 

Consumer testing groups later expanded the scope and found similar red flags. Follow-up lab work — which examined dozens of widely sold braiding hair products — detected lead, other heavy metals, and VOCs known to irritate the lungs, damage organs, and, in some cases, be associated with cancer and reproductive harm. Those tests raised particular alarm for stylists and salon workers, who face repeated, daily exposure when they heat, braid, and manipulate extensions for clients. 

This is especially urgent for Black communities. Braiding and protective styles are cultural mainstays and, by most estimates, millions of Black women wear extensions at least once a year. That routine, combined with ingredient-blinded products (some extensions list no ingredients at all) and the fact that people often keep extensions installed for weeks, means potential exposures are both more frequent and more prolonged than with typical cosmetic products. Experts and advocates warn this could compound existing health disparities, particularly for conditions like aggressive breast and uterine cancers. 

Researchers and public-health groups are calling for stronger oversight, better labeling, and more transparency from manufacturers. Some states have already moved to ban or limit harmful chemicals in cosmetics; federal reform proposals such as the Safer Beauty Bill aim to make ingredient disclosure and safety testing mandatory. In the meantime, public-interest groups advise consumers to seek biobased or better-sourced alternatives and to use independent databases to vet products.