What is unclear when it comes to period products, however, is whether PFAS in these products manage to seep into the bloodstream in higher concentrations than they do via other products, like food packaging or shampoo. “The short answer is we don’t know because this is such an understudied topic,” Dr. Kioumourzoglou said.
Are PFAS in most period products?
It’s hard to know. There has been “a long history of lack of oversight” when it comes to period products, said Dr. Sharra Vostral, a professor of history at Purdue University who has studied the policy, design and approval processes behind menstrual products. In general, she said, they “have not really been fully tested and understood.”
Though menstrual cups, tampons and pads are considered medical devices, the Food and Drug Administration classifies them as low or medium-high risk. Thinx confirmed, in an email to The Times, that it registered its underwear as a medical device. Because of the classification, these products are not subject to rigorous testing, nor do manufacturers need to label all the materials used in them.
It is unclear, then, which period products contain PFAS or other environmental toxins, as well as the concentration of toxins in those products and how much might be absorbed by the body, Dr. Kioumourzoglou said. An environmental blog, after testing dozens of products in 2022, found PFAS in pads, panty liners and incontinence pads.
Meanwhile, peer-reviewed studies of these products have found inconsistent results. A recent analysis by Dr. Kioumourzoglou and several colleagues examined nearly two dozen studies; some studies found significant amounts of an array of toxins in period products and others found only trace amounts that present “low risk to health,” leading the authors to conclude that further research is needed.
When it comes to period underwear, some experts suggest that PFAS might be washed away after a few runs through the laundry, but there isn’t scientific research to confirm that. And studies have not looked specifically into whether PFAS found in period underwear were absorbed in the body — even the Thinx lawsuit was centered on its marketing and not around any health issues the consumers may have had.
Not all period underwear, however, is created equal. The original Sierra magazine investigation and other product testers have identified some brands that they claim are free of toxins.
