The plastic-strengthening chemical bisphenol A (BPA) has long drawn fire for possible health risks. But a common substitute called bisphenol S (BPS) may not be much safer. “We found that BPS is disrupting endocrine systems by mimicking estrogen, thyroid hormone, and the enzyme aromatase that converts testosterone to estrogen,” says Nancy Wayne, a reproductive endocrinologist and professor of physiology at the David Geffen School of Medicine at UCLA. “In side-by-side experiments, we showed that [exposure to BPS] is similar to BPA.” While questions remain, limit your use of plastics that come in contact with food and drink as much as possible, suggests Wayne.

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