According to the researchers, dozens of hazardous substances were detected, with some synthetic fibres showing particularly high levels of chemical signatures.
A new study has found that widely used hair extensions contain multiple hazardous chemicals, including substances linked to cancer, hormone disruption and reproductive harm.
The research, conducted by scientists at the Silent Spring Institute, a scientific research organisation, identified 169 different chemicals across 43 hair extension products.
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The study which was published in February 2026 in the journal Environment & Health raises concerns about the safety of products commonly used for braiding.
The findings show that both synthetic and natural hair extensions, including those marketed as "human hair" or plant-based, contain chemical contaminants, suggesting the issue is widespread across the industry.
Chemical risks
According to the researchers, dozens of hazardous substances were detected, with some synthetic fibres showing particularly high levels of chemical signatures.
Among the chemicals identified were phthalates, organotin compounds, flame retardants and other industrial substances.
About 10 per cent of samples contained organotins, with some concentrations exceeding European Union safety limits for consumer products.
It noted that Phthalates were found in roughly half of the samples, including in products labelled "phthalate-free," raising concerns about product labelling.
The study also identified 17 chemicals linked to breast cancer across most of the tested products, while about 91 per cent contained at least one substance listed under California's Proposition 65 as causing cancer or reproductive harm.
"We were especially surprised to find organotins," said Elissia Franklin, the study's lead author was quoted. "These are commonly used as heat stabilisers in PVC and have been linked with skin irritation."
Exposure concerns
The researchers said the way hair extensions are used may increase exposure to these chemicals.
Extensions are often worn for long periods and remain in close contact with the scalp, while heat applied during styling can release volatile organic compounds (VOCs).
This means users and hairdressers may be exposed through both skin contact and inhalation.
A report by CNN, citing a Consumer Reports investigation, also found lead in most braiding hair products tested, while all samples contained VOCs that can pose health risks.
Experts say hair braiders may face the highest exposure due to repeated and prolonged contact.
"Those braiders are the most vulnerable population," Ms Franklin said.
"It shouldn't be on the hair braiders to make individual decisions," she added, calling for safety regulations.
Regulation, transparency gaps
The study highlights concerns about the lack of regulation in the hair extension industry, where manufacturers are not required to fully disclose product ingredients.
Researchers said this limits consumers' ability to assess risks and makes proper safety evaluation difficult.
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"Companies rarely disclose the chemicals used to achieve these properties, leaving consumers in the dark about the health risks from prolonged wear," Ms Franklin said.
The findings have also raised concerns about health disparities, as hair extensions are predominantly used by Black women.
Studies show that more than 70 per cent of Black women use hair extensions at least once a year, often for extended periods.
"This is an industry that has long overlooked the health of Black women, who should not have to choose between cultural expression, convenience, and their health," Ms Franklin said.
The researchers called for stronger regulation, improved product labelling and further studies to better understand the long-term health effects.
