A study by Young et al, published in the journal Environmental Science & Technology, found that nail polish contains plasticizers to make it flexible and chip-resistant, but as endocrine disruptors, these chemicals–which can be absorbed into skin or inhaled–may adversely affect reproductive health, fetal development, and thyroid function.

Consumers should not be misled by polishes that advertise they are “3-free”, or “5-free” (for example), which supposedly indicate the number of chemicals the products are “free” from, because there are no uniform standards for such labeling, and the substitute ingredients may be just as toxic.