Tampons sold in the UK have been found to contain high levels of a toxic pesticide called glyphosate. A new report shows one tampon brand had 40 times more glyphosate than what’s legally allowed in drinking water. Experts are concerned because the vagina absorbs chemicals directly into the bloodstream, skipping the body’s usual filters.

Glyphosate is a common weedkiller linked to cancer, Parkinson’s, and other health issues. It’s often used to grow cotton, which is a main ingredient in tampons. Researchers also found a chemical byproduct of glyphosate, called AMPA, in the products. These findings raise serious concerns about how safe menstrual products really are.

Health experts say more testing and regulation are needed. They’re calling on the government to make sure period products are free from harmful pesticides. Many people don’t realize these chemicals might be in products they use every month.