Can chemicals in shampoo, lotion, and other personal care products affect thyroid health during pregnancy?

What's actually in it

Personal care products contain dozens of chemicals that absorb through skin. The list includes phthalates (fragrance solvents), parabens (preservatives), benzophenone (UV filters in some products), triclosan (antimicrobials), and others. These chemicals accumulate daily with every shampoo, moisturizer, and cosmetic application.

Several of these chemical classes directly interfere with thyroid hormone metabolism. They compete for thyroid-binding proteins in blood, disrupt the enzymes that convert T4 to T3, and affect thyroid receptor signaling. During pregnancy, when thyroid demands increase to support fetal brain development, this interference carries significant consequences.

What the research says

A 2026 prospective cohort study in Environ Int measured personal care product chemical exposure in pregnant women and analyzed their thyroid function. Higher combined exposure to personal care product chemicals was linked to disrupted TSH, free T4, and free T3 levels during pregnancy.

The study used a real-world mixture approach, assessing the combined effect of multiple chemicals as people actually encounter them. Individual chemical effects were weaker; it's the daily cumulative load from using multiple products that drives the thyroid disruption.

Pregnant people use personal care products multiple times daily. Switching to fragrance-free shampoo, conditioner, and body lotion removes the largest chemical contributors. Avoiding products with "parfum" or "fragrance" listed as ingredients eliminates the phthalate source. Choosing paraben-free formulations removes another contributor. These swaps are straightforward and don't require giving up routine hygiene products.