Can nail polish damage your thyroid?

What's in nail polish

Many nail polishes contain dibutyl phthalate (DBP), a plasticizer that keeps the polish flexible and chip-resistant. DBP is also in hair spray, perfume, and some cosmetic coatings. You absorb it through your nails, cuticles, and the skin around your fingers. Nail salon workers who breathe polish fumes daily face especially high exposure.

DBP doesn't stay on your nails. It enters your bloodstream and travels throughout your body, including to your thyroid gland.

What the research says

A 2026 study in Annals of Medicine found that DBP directly damages the thyroid. It triggers a violent form of cell death called pyroptosis in thyroid follicular cells, the cells responsible for making thyroid hormones.

The damage follows a specific chain reaction. DBP disrupts the NRF2/KEAP1 protective pathway, which normally shields cells from oxidative stress. With that defense down, inflammation spirals through the NF-κB pathway, and the cells essentially self-destruct.

The result: fewer functioning thyroid cells, reduced hormone output, and chronic inflammation in the thyroid tissue.

How to reduce your exposure

Choose nail polishes labeled "DBP-free" or look for "3-free," "5-free," or "10-free" formulas that exclude the most concerning chemicals. If you visit nail salons, pick ones with good ventilation. Water-based nail polishes skip phthalates entirely.