Period underwear may contain troubling chemicals—but the real problem is much bigger

Menstrual products are under-regulated around the world

underwear and tampons on a pink background
No one is keeping tabs on your tampons.DepositPhoto

If you’re someone who menstruates, you might reasonably assume that the products you use to deal with your period aren’t actively bad for your health. Unfortunately, that’s not necessarily the case; a number of studies have found surprising chemicals (not all of which are necessarily harmful, but many of which have not been studied in relation to vaginal health) in pads, tampons, and cups.

The latest menstrual product to come under scrutiny is period underwear. On January 7, journalist Jessian Choy reported in Sierra that a nuclear scientist had found a group of chemicals called PFAS in several pairs of Thinx period underwear she mailed to him for testing.

PFAS (short for per- and polyfluoroalkyl substances) have been found in many materials, including food wrappers, water-repellent fabrics, cleaning products, and paints. They’re linked to a number of health problems, including cancer and decreased fertility.

When Thinx commissioned outside experts to test their underwear, they did not find any traces of the chemicals (Thinx provided copies of the reports to Popular Science). CEO Maria Molland said in an email, “Recognizing the serious nature of these issues, we are working to dramatically expand the list of chemicals that we test for in our products and develop a robust safer chemicals policy across our entire family of brands. If any unregulated PFAS chemicals are ever found in our products, we will move swiftly to remove them.”

At this point you might be wondering: who’s in charge of monitoring these things and making sure they aren’t dangerous, anyway? It turns out that menstrual products of all kinds are under-regulated, according to Jamie McConnell, director of programs and policy at Women’s Voices for the Earth, a Missoula-based nonprofit focused on menstrual, cleaning, and personal care product safety.

“Women’s health just tends to be disregarded in policy,” she says. “It’s kind of mind-blowing when you think about how and where these products are used; in some cases they’re inserted into the body or they come in close contact with very sensitive vaginal tissue, and yet there’s no real clear requirements for substantiating the safety of ingredients that are used in these products.”

Generally, the Food and Drug Administration considers menstrual products to be medical devices, which means that the companies who manufacture them aren’t required to put a list of ingredients on the product’s label. It’s not clear whether this rule applies to menstrual underwear, which isn’t listed alongside tampons, pads, and cups as a medical device in the Code of Federal Regulations.

“At some point … the FDA’s going to need to update their requirements for how they regulate these products, especially as we see more innovation in the industry,” McConnell says. “It’s great for people who menstruate to have different products to access to control their period, but there just needs to be stronger oversight.”

Companies do need to notify the FDA when they are planning to market a new medical device or one that is substantially different from previous versions. This is called a Premarket Notification, and is meant to show that the product is at least as safe and effective as similar ones on the market. For tampons, this includes an evaluation of whether the product enhances growth of the bacteria that can cause toxic shock syndrome. However pads and menstrual cups may be exempt from this requirement.

The lack of regulation surrounding the safety of menstrual products is a global issue, says Louise Klintner, a doctoral candidate at the Lund University School of Economics and Management in Sweden who is researching this issue. “In many parts of the [European Union] there is only the EU general product safety directive that governs the safety of menstrual products,” she said in an email to Popular Science.

In much of the world, manufacturers of medical devices would have to disclose the ingredients used, unlike in the U.S. But only a few other countries actually give menstrual products this designation. “Because menstrual products are generally not classified as medical devices and explicit regulations or standards have not been developed for menstrual products as their own category, these products often fall between the stools of regulations and testing,” Klintner said.

However, she added, the Swedish Institute for Standards and other groups are working to fill this gap by creating standards for menstrual products that could be used around the world.

Change is also on the horizon in the U.S.. On October 19, Governor Andrew Cuomo signed a bill making New York the first state where companies will have to include “a plain and conspicuous printed list of all the ingredients” on the packaging of menstrual products.

"Practically every product on the market today is required to list its ingredients, yet these items have inexplicably evaded this basic consumer protection," Cuomo said in a statement. "It's part of the pervasive culture of inequality in our society that has gone on for too long.”

Several bills that would target menstrual products have also been introduced into Congress. The Menstrual Products Right to Know Act of 2019, introduced by Representative Grace Meng of New York, would require companies to disclose the ingredients used in their menstrual products nationwide. Meanwhile, the Robin Danielson Feminine Hygiene Product Safety Act of 2019, sponsored by Representative Carolyn Maloney of New York, would require the National Institutes of Health to study whether the chemicals found in menstrual products pose any health risks, from cancer and infertility to yeast infections.

Cause for concern

When researchers have tested menstrual products, they have discovered unfriendly substances ranging from benzene to chloroform. One recent investigation was sparked by reports from South Korean media outlets in 2017 that new sanitary pads might be responsible for the disrupted menstrual cycles and rashes that some consumers were experiencing. Researchers sampled sanitary pads (as well as diapers) from around the world, and discovered varying amounts of phthalates and volatile organic compounds in every brand. The chemicals may have been released from synthetic plastics in the pads intended to absorb liquid. They can be absorbed through the skin and are associated with cancer, asthma, and menstrual irregularities, as well as disrupting the cardiovascular, reproductive, and endocrine systems.

“A big concern with a lot of these endocrine disrupting chemicals is that the dose doesn’t make the poison. It’s not always the higher doses that we need to be concerned about. Sometimes the really low doses can have the most profound effects,” Jodi Flaws, a coauthor of the paper and professor of comparative biosciences at the University of Illinois Urbana-Champaign, said in an interview with Living on Earth. “We can’t just assume, because it’s a low dose, that it’s a safe dose.”

Finding potentially harmful chemicals in menstrual products is particularly worrying for a number of reasons. Nearly half the population menstruates, which means they will have to deal with their period for several days every month for decades on end. So menstrual products are going to spend a lot of time inside or next to people’s bodies; a person might use more than 10,000 tampons in their lifetime. What’s more, vaginal and vulvar tissue might be especially vulnerable to dangerous chemicals because it’s so thin and absorbent. However, it’s not clear yet how big of a problem this is, says Alexandra Scranton, director of science and research at Women’s Voices for the Earth.

“It’s not an area of the body that gets researched like other areas of the body,” she says. “There’s a lot of really basic information on how we absorb chemicals through vaginal tissue and through vulvar tissue that we don’t know.”

Researchers also don’t necessarily know what substances to test for. The Sierra report is the first she’s heard of anyone investigating PFAS. “I don’t think anyone’s ever thought to look for it before,” she says.

So there’s still a lot of uncertainty surrounding what exactly is in menstrual products and whether these ingredients actually pose a danger to our health. And the regulations guiding the industry are still a work in progress. But McConnell sees these efforts as akin to those championing affordable menstrual products and ditching the hated tampon tax.

“People who menstruate deserve to have access to [menstrual] products—whether they’re at school or incarcerated or in a public restroom—because it is a necessity just like toilet paper is,” she says. “But the other part of menstrual equity is having the right to know what ingredients are in these products, and that [those ingredients aren’t] going to potentially impact your health.”