Using the Yeast Estrogen Screen to Measure the Estrogenicity of Personal Care Products

PAC Gym

Many cosmetic and pharmaceutical products manufactured for daily use contain endocrine-disrupting compounds. These compounds can occur naturally (e.g. phytoestrogens) or can be man-made (e.g. UV filters or phthalates). Many bind to estrogen receptors, leading to sex reversal, infertility, menstrual irregularities, miscarriage, and breast cancer. The purpose of this study was to detect and quantify estrogenic compounds in a variety of personal care products, including shampoos, conditioners, lotions, sunscreens, and moisturizers, using the yeast estrogen screen (YES). Two strains of recombinant Saccharomyces cerevisiae containing plasmids that resulted in the expression of either the alpha or beta isoforms of human nuclear estrogen receptor (ER) were used to quantify ER agonism in ethanol extracts of 32 personal care products, each of which was measured in triplicate. Estrogenic compounds in a sample bound to the ER alpha or ER beta receptors, resulting in the dose-dependent expression of beta-galactosidase. The yeast cells were then lysed to release the beta-galactosidase, which cleaved a colorimetric substrate and produced a yellow to red product, with the degree of color change correlating to the concentration of estrogenic compounds. Of 32 personal care products tested, over half were positive for the presence of estrogenic compounds. The results of this study indicate that many popular personal care products contain estrogenic endocrine-disrupting chemicals and suggest that caution is warranted when using such products.