Toxic chemicals in African American hair products may disrupt the endocrine system

By Liz Meszaros, MDLinx
Published September 28, 2018

Key Takeaways

African American women may be exposed to dozens of hazardous ingredients—many of them endocrine-disrupting chemicals—through the hair products they use, according to results published in Environmental Research.

Researchers at Silent Spring Institute, Newton, MA, and Battelle Memorial Institute, Columbus, OH, conducted the study, which is the first to measure concentrations of endocrine-disrupting chemicals in hair products marketed specifically for African American women.

And although the chemicals detected are in no way unique to hair products used by African American women, the measured levels were generally higher than in other hair products.

“Chemicals in hair products, and beauty products in general, are mostly untested and largely unregulated,” said lead author Jessica Helm, PhD, scientist, Silent Spring, a 501(c)3 public charity and scientific research organization dedicated to the study of environmental factors in women’s health. “This study is a first step toward uncovering what harmful substances are in products frequently used by black women, so we can better understand what’s driving some of the health issues they’re facing.”

Compared with other ethnic groups of women, African Americans experience puberty younger, and have higher rates of hormone-mediated problems, including preterm birth, uterine fibroids, and infertility.

Using gas chromatography/mass spectrometry, Dr. Helm and colleagues assessed 18 hair care products, including hot oil treatments, anti-frizz hair polishes, leave-in conditioners, root stimulators, hair lotions, and hair relaxers. They tested each product for the presence of 66 endocrine disruptors associated with a variety of health effects, including reproductive disorders, birth defects, asthma, and cancers. These chemicals belonged to 10 classes: ultraviolet filters, cyclosiloxanes, glycol ethers, fragrances, alkylphenols, ethanolamines, antimicrobials, bisphenol A, phthalates, and parabens.

They found 45 endocrine disruptors in all, with a range of 4 to 30 in each product tested. Eleven products contained 7 chemicals prohibited in the European Union (EU) or regulated under California’s Proposition 65. Hair relaxers for children had the highest levels, with 5 chemicals prohibited in the EU or regulated under Proposition 65.

Chemicals found at the highest levels included cyclosiloxanes, parabens, and diethyl phthalate (DEP), a fragrance marker; DEP was the most frequently found chemical.

Other findings:

  • Root stimulators, hair lotions, and hair relaxers commonly contained parabens, fragrances, nonylphenols, and DEP
  • Anti-frizz products were most frequently found to contain cyclosiloxanes at the highest concentrations of any chemical measures
  • All products contained fragrance chemicals, and 78% had parabens
  • A full 84% of the chemicals detected were not listed on product labels

Dr. Helm and fellow researchers found that chemicals detected at concentrations of more than 1,000 µg/g were included on the label only 54% of the time, and those detected at concentrations of less than 100 µg/g were labeled 8% of the time. Only 16% of chemicals found in concentrations above the Method Reporting Limit (MRL) were listed on the ingredient label.

Parabens were the most accurately labeled, while UV filters and fragrance chemicals were generally not listed.

“Unfortunately, companies aren’t required to disclose everything that’s in their products, so it’s hard for consumers to make informed choices,” said co-author Robin Dodson, ScD, environmental exposure scientist, Silent Spring.

Hair products were the focus of the study for several reasons. African American women buy and use more hair products than women of other races, and more commonly use products such as hair straighteners and moisturizers, often to meet societal beauty norms.

According to national biomonitoring data from the Centers for Disease Control and Prevention (CDC), African American women have higher levels of some phthalates and parabens compared with white women.

Drs. Helm and Dodson agreed that this is consistent with what they found in this study.

“Black women are overexposed and underprotected from toxic chemicals,” said Janette Robinson Flint, executive director, Black Women for Wellness, a nonprofit based in California that conducts research and education on toxic chemicals in personal care products through its Healthy Hair Initiative. “This study is evidence that hair products are an important source of toxic chemicals and that we need to remove these risks to protect black women’s lives and prevent harm.”

Dr. Helm hopes that these results will bring about better ingredient disclosures and safer products from manufacturers. For consumers, she advised limiting the number of products used, searching for products marked “paraben-free” or “fragrance-free,” and buying products that are plant-based or made from organic ingredients.

“Given the exposure and endocrine-mediated health disparities experienced by black women, new research and regulatory activities should consider the effects of ethnic differences in product use on exposures and health. Additional research is needed on the chemical composition of products marketed to and used by black women and on product use and exposure in this population. Risk assessments should include dermal routes of exposure and coexposures in susceptible populations including black women,” they concluded.

This work was partially supported by the Rose Foundation, the Goldman Fund, and Hurricane Voices Breast Cancer Foundation.

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