A recent review published in Current Environmental Health Reports found that two types of chemical hair straighteners - relaxers and keratin treatments - each contain multiple classes of known toxic chemicals.
In short:
- Across 21 studies and reports, hair straightening treatments were found to contain multiple chemicals of concern, including endocrine-disrupting chemicals (EDCs), carcinogenic chemicals, and heavy metals.
- Formaldehyde, a known carcinogen, was most frequently found in keratin treatments.
- Fragrance ingredients were the most commonly identified chemicals of concern in hair relaxers, along with EDCs such as phthalates and parabens.
- Studies also found that salon workers who handled these products had higher urinary levels of toxic chemicals at the end of their shifts.
Key quote:
“Upstream interventions, including those targeting structural racism and market-based strategies, are needed to reduce environmental exposure and health inequities experienced by communities at risk.”
Why this matters:
Many beauty and personal care products, including hair products, contain mixtures of dozens of synthetic chemicals. Many of these chemicals have been linked to harmful health effects and adverse reproductive outcomes, while others have not been thoroughly studied, leaving their potential risks poorly understood. Fragrance in particular is a blind spot: because fragrance formulas are protected as trade secrets, manufacturers are not required to disclose their full chemical makeup, so many of the specific compounds in "fragrance" remain unknown, even though some are themselves EDCs. Structural racism has shaped the use of hair straighteners for generations, and continues to drive disproportionate chemical exposure among Black and Latina women – and the salon workers, often women of color themselves, who apply these treatments. The authors of this review call for both regulatory action to prevent exposure and community-led interventions to address this risk.
Related EHN coverage:
- Marissa Chan on solutions to harmful beauty products
- For thousands of Americans, unhealthy chemical exposures at work are a needless reality
More resources:
- Beauty + Justice, a limited series podcast hosted by Tamarra James-Todd, features researchers, companies and organizations working toward a toxics-free future for beauty products.
- Inside Climate News: Q&A: Ami Zota on the hidden dangers in beauty products—and why women of color are particularly at risk. (Dr. Zota is one of the authors of the paper)
- Webinar recording: Personal care product use & chemical exposure among Black, Latina & Vietnamese women in California: Findings from the CAPABLE project, hosted by the Collaborative for Health and Environment.
