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Member Research and Reports

Member Research and Reports

Berkeley Study Finds That Teen Girls See Big Drop in Chemical Exposure with Switch in Cosmetics

A new study led by researchers at the University of California, Berkeley School of Public Health and Clinica de Salud del Valle de Salinas demonstrates how even a short break from certain kinds of makeup, shampoos, and lotions can lead to a significant drop in levels of hormone-disrupting chemicals in the body.

The results, published in March in the journal Environmental Health Perspectives, came from a study of 100 Latina teenagers participating in the Health and Environmental Research on Makeup of Salinas Adolescents (HERMOSA) study.

HERMOSA is a community-university collaboration between UC Berkeley, Clinica de Salud del Valle de Salinas, and a team of youth researchers from the CHAMACOS Youth Council, a project to involve young people in public health and the environment.

Researchers provided teen study participants with personal care products labeled free of chemicals such as phthalates, parabens, triclosan, and oxybenzone. Such chemicals are widely used in personal care products, including cosmetics, fragrance, hair products, soaps and sunscreens, and have been shown in animal studies to interfere with the body’s endocrine system.

“Because women are the primary consumers of many personal care products, they may be disproportionately exposed to these chemicals,” said study lead author Dr. Kim Harley, associate director of the UC Berkeley Center for Environmental Research and Children’s Health. “Teen girls may be at particular risk since it’s a time of rapid reproductive development, and research has suggested that they use more personal care products per day than the average adult woman.”

Analysis of urine samples before and after a three-day trial in which the participants used the lower- chemical products found significant drops in levels of these chemicals in the body. Metabolites of diethyl phthalate, commonly used in fragrances, decreased 27 percent by the end of the trial period. Methyl and propyl parabens, used as preservatives in cosmetics, dropped 44 and 45 percent respectively. Both triclosan, found in antibacterial soaps and some brands of toothpaste, and benzophenone-3 (BP-3), found in some sunscreens under the name oxybenzone, fell 36 percent.

The researchers noted that cosmetics and personal care products are not well-regulated in this country, and obtaining data about health effects from exposure, particularly long-term ones, is difficult. But they say there is growing evidence linking endocrine-disrupting chemicals to neurobehavioral problems, obesity, and cancer cell growth.

“We know enough to be concerned about teen girls’ exposure to these chemicals. Sometimes it’s worth taking a precautionary approach, especially if there are easy changes people can make in the products they buy,” said Dr. Harley.

The California Breast Cancer Research Program of the University of California helped support this research. Chemical analyses were performed through Biomonitoring California, a California Department of Public Health program that tracks levels of chemicals in California residents.

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