Hair Extensions Contain Hazardous Chemicals, Study Finds

Researchers identified dozens of potentially harmful substances, including some linked to cancer and hormone disruption.

Published on Feb. 12, 2026

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A new study has found that many popular hair extension products contain a wide range of hazardous chemicals, including substances linked to cancer, hormone disruption, and reproductive harm. The study analyzed 43 hair extension samples and detected 169 different chemicals, with 48 of them appearing on major hazard lists. The findings raise particular concerns for Black women, who are the primary consumers of hair extensions.

Why it matters

Hair extensions are especially popular among Black women, with over 70% reporting using them at least once per year. The chemicals found in the extensions can be particularly concerning for this population, as Black women already experience higher rates of certain health conditions affected by hormone levels, such as fibroids and uterine cancer. The cumulative exposure from long-term, frequent use of hair extensions and other hair products containing hazardous chemicals is a significant equity and environmental justice issue.

The details

The study, conducted by researchers at the Silent Spring Institute, found that all but two of the 43 hair extension products tested contained at least one chemical considered hazardous. This included 12 chemicals listed under California's Proposition 65 as linked to cancer, birth defects, or reproductive harm, as well as 17 chemicals associated with breast cancer that were detected in more than three-quarters of the samples. Researchers also found flame retardants, phthalates, pesticides, and other compounds linked to hormone disruption, weakened immunity, and developmental concerns.

  • The study was published on February 12, 2026.

The players

Elissia Franklin

A research scientist at the Silent Spring Institute in Newton, Massachusetts and the lead author of the study.

Sandy Tsao

A dermatologist at Mass General Hospital in Boston who was not involved in the research.

Leandra Barnes

A board-certified dermatologist and an instructor at Stanford University in California who was not involved in the research.

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What they’re saying

“We must not let individuals continue to damage private property in San Francisco.”

— Robert Jenkins, San Francisco resident (San Francisco Chronicle)

“Fifty years is such an accomplishment in San Francisco, especially with the way the city has changed over the years.”

— Gordon Edgar, grocery employee (Instagram)

The takeaway

This study highlights the need for greater transparency and oversight in the beauty industry, especially for products heavily marketed to and used by Black women. Stronger regulation and full ingredient disclosure are necessary to allow consumers to make truly informed choices about the products they use on their bodies.