Thinx Again: On the Problem with PFAS in Our Period Products

This month, the large period underwear company Thinx reached a settlement on a class action lawsuit against them for misleading customers by claiming their products were “nontoxic, harmless, sustainable, organic, and otherwise safe for women and the environment” when in fact they contain PFAS. They agreed to pay up to $5 million to reimburse customers. (Consumers can apply for a refund for up to three pairs of Thinx underwear: $7 per pair if you still have your receipt, $3.50 per pair if you don’t. Note that they cost the user $35 per pair to purchase.) Despite settling, Thinx maintains they didn’t do anything wrong and claim that “PFAS has never been part of the brand’s product design.” 

So what are PFAS and does it matter that they were found in a period product?

PFAS stands for per- and poly-fluoroalkyl substances, a group of chemicals that contains fluorines. There are at least 4730 in circulation in our environment as the result of their wide use in numerous industrial and personal products. Discovered in the 1930s, and in widespread use since the 1950s, PFAS are found in a variety of common products many of us use daily, including nonstick cookware (the ‘fl’ in Teflon refers to the fluorines), waterproof clothing, stain-resistant fabrics, food packaging, microwave popcorn bags, dental floss, and cosmetic products, like body lotion, foundation, mascara, shampoo, sunscreen, and more.

Because of their ​​extreme environmental persistence – they basically never degrade in our environment – PFAS are referred to as “forever chemicals.” They are found all over the planet, including in the bodies of polar bears in the Arctic and penguins in Antarctica. And they also accumulate in our bodies over time (this is called bioaccumulation) and are now found in the blood of basically all Americans, across all ages. 

One of many classes of potent endocrine-disrupting chemicals (EDCs), the most commonly studied PFAS – perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) – were phased out of production in the United States in 2002 and 2015 as research has revealed their health risks.  But because they are so persistent, they haven’t disappeared just because they were phased out. They are still in our soil and water, and still in products produced with them prior to the phase out—like older Teflon and other non-stick pots and pans—as well as products we import from other countries in which they are still in use. And as the older PFAS have been phased out, newer short-chain PFAS have replaced them, which have not been well studied and eventually may prove to be just as toxic. It’s one of the newer PFAS that was found at high levels in Thinx underwear. 

The Problem of Toxins in Our Menstrual Products

Thinx is hardly the only menstrual product company with PFAS in their product though. Since the news of the Thinx scandal broke, various media outlets have sent other brands’ products to independent labs to be tested as well. The environmental blog Mamavation recently sent in dozens of products for testing and found evidence of PFAS in nearly two thirds of period underwear, as well as nearly half of menstrual pads, panty liners, and incontinence pads and nearly a quarter of tampons. 

Of note, evidence of PFAS was detected in several companies’ pads and tampons that are advertised as “organic.” This underscores the fact that labels like ‘non-toxic,” “organic,” and “natural” can simply be empty marketing promises. They don’t guarantee that those products have been tested and verified for these claims – or for health and safety. 

Advocates and scientists, including myself, have long warned that there’s not enough oversight on the possible health risks of toxins in menstrual products. 

 Menstrual products, including period underwear, tampons, pads, and menstrual cups, fall under the FDA regulatory category of “medical devices.” Contrary to what you might assume, that means they are actually subject to a lower standard of scrutiny than even cosmetics.They undergo little to no safety testing conducted by the FDA before hitting the market and – and unlike with cosmetics products – manufacturers aren’t even required to disclose all the ingredients they contain. That makes it very hard even for educated consumers to discern which products have had their products independently tested for PFAS and other contaminants. 

As I discussed in a previous article on this topic, an important study titled “Chem Fatale” by Women’s Voices For The Earth on the potential health risks associated with the use of menstrual products found that tampons and pads sometimes contain the following possible ingredients, all unlisted on the packaging:

• Dioxins from the bleaching process
• Furans
• Pesticide Residues
• Unknown Fragrance Chemicals
• Adhesive Chemicals, such as methyldibromo glutaronitrile

The possible health effects of these exposures is a topic that is woefully understudied. A 2022 review of nearly two dozen studies measuring various environmental toxins in menstrual products concluded that all the studies detected toxins – some found significant levels, while others concluded that the levels were low enough to pose little risk.

Menstruators may use over 10,000 menstrual products over our lifetimes. Not only are we potentially at risk, but what’s absorbed into our bodies can impact our fertility and also be passed onto our offspring. I’d say further research is urgently warranted.

How Much PFAS Exposure Are We Getting From Thinx or Other Menstrual Products?

Remember, the charge against Thinx was that its marketing was misleading – not that the PFAS in its products necessarily harmed users.

In fact, we don’t even know how much of the PFAS found in Thinx or other menstrual products is actually absorbed into the bloodstream. Those studies simply haven’t been done. How much PFAS absorption occurs through the skin in general is currently unstudied in humans, but a recent study on the effects of PFOA on the immune systems of mice found that dermal absorption of the chemical was as harmful as when it was ingested orally. And we know from comparable studies on human exposure to similar chemicals such as brominated flame retardants that dermal absorption can be a significant source of exposure. Plus, the vaginal/vulvar tissue is especially absorbent compared to the skin on your body.

Some researchers suggest that washing period panties over time will remove PFAS. But that just means they end up as forever chemicals in our water and environment, so that’s not really a long term solution. And we obviously can’t pre-wash tampons and pads. Further, in a study by Greenpeace, not only was contact with water repellent clothing and hiking gear (i.e. rain jackets, rain pants, and footwear) a source of PFAS exposure, but concentrations of PFAS were increased once the clothing was weathered compared to the original unweathered items.

On the other hand, it’s certainly possible that any exposure from period underwear is minimal compared to the amounts we’re exposed to through our water, our foods (via contaminated soil and food packaging materials), and other consumer products. 

Indeed, perhaps the largest source of exposure is our drinking water. PFAS contaminate the drinking water in almost every state. Last year, the EPA issued guidelines with new limits for how much PFOS and PFOA should be in drinking water. Back in 2016, they had set a limit of 70 parts per trillion (ppt) for both. At least 100 million Americans likely have drinking water that exceeds that limit. But now the agency says that in light of new research showing even very small amounts are harmful to health, the new limit should be 0.02 ppt for PFOS and 0.004 ppt for PFOA. That’s a decrease of more than a thousandfold. But the EPA’s guidelines aren’t currently legally binding.

What Are The Health Risks Linked to PFAS?

Though the FDA has said that just because a given product has “detectable” levels of PFAS doesn’t necessarily mean it poses a safety concern, when it comes to endocrine-disrupting chemicals (EDCs) like PFAS, studies have shown that chronic, recurrent exposure to even barely measurable amounts may be impactful, as it only takes amounts in parts-per-million to influence our hormones. 

I’ve spoken with audiences and my patients about the health issues of EDCS, including PFAS, for decades, and dedicated a chapter on it in my latest book Hormone Intelligence, which centers on hormonal and reproductive health, as well as one in my book The Adrenal Thyroid Revolution, where I discuss the impact of EDCs, including PFAS, on thyroid health. 

Many high quality studies have linked long-term exposure to PFAS to numerous health risks, including increased cholesterol levels, decreased vaccine response in children, changes in liver enzymes, increased risk of kidney, testicular cancer, breast cancer, obesity, type 2 diabetes, and more. PFOA has been classified as a potential carcinogen. PFAS are neurotoxic and immunotoxic, and because they can accumulate in the lungs, one study suggests they could possibly be associated with more severe COVID. 

As endocrine-disrupting chemicals (EDCs), PFAS can interfere with our hormone systems, causing major problems for reproductive health. Studies have linked long-term PFAS exposure with menstrual irregularities and ovarian dysfunction, as well as disorders like polycystic ovarian syndrome, endometriosis, thyroid hormone deficiency, fertility issues, and earlier age of menopause. 

According to a 2020 investigation in the New York Times, high prenatal PFAS exposures can impact thyroid function, metabolism, and immunity of both mother and child. Some studies have suggested that prenatal exposure to PFAS could lead to lower birth weight and increase the risk of preterm birth. Women exposed to PFAS during pregnancy may also have higher risks of gestational diabetes and pre-eclampsia. Their babies are later at increased risk of childhood obesity and infections. 

Of note, knowledge of the health risks of PFAS isn’t new. The FDA has been aware of how they affect the body since the 1960s. DuPont, who first developed PFOA, submitted evidence on their harms to the FDA in 1966. If you haven’t seen the 2019 movie Dark Waters with Mark Ruffalo, it’s worth watching – I’ve done so twice!

How to Reduce Your Personal Exposure to PFAS

At this point, it’s impossible for any of us to avoid all PFAS completely no matter how clean and green we try to live – they are just that ubiquitous. But we can reduce our personal body burden (e substance in the human body) by lessening our exposure. 

I personally used my own reusable cloth pads since I was 15 years old, not just for personal health but because disposable menstrual products generate an enormous amount of environmental waste. When they finally became available in the 1990s, I used organic tampons  when a cotton pad wasn’t practical (think overnight call in the hospital). 

Here are some steps you can take to reduce your PFAS exposure:

• Filter drinking water with an activated carbon or reverse osmosis filtration system.
• Avoid stain and water-resistant fabrics, sprays, carpets, and furniture. The Green Science Policy Institute has lists of PFAS-free consumer products – from rain gear to car seats.
• Instead of nonstick cookware, use stainless steel, enamel, glass or cast iron cookware.
• Avoid takeout food containers and wrappers. If you do use them, transfer food out as soon as possible and don’t reheat in the container. 
• Avoid cosmetics and personal care products with “PTFE” or “fluoro” listed as ingredients. The Environmental Working Group’s database can help identify products that do not contain PFAS. 

When it comes to menstrual products: 

• If you’re hooked on menstrual underwear, check out guides from Better Goods and Mamavation to find PFAS-free options.
• Try menstrual cups or discs, which are typically made with body-safe silicone, and which rather than absorbing your menstrual flow, collect it, allowing you to empty, rinse, and reuse it as needed.
• If you are using pads or tampons, choose organic and look for companies that disclose their ingredients.
• If you’re up for the extra work it takes, on menstruating days when you’re just chilling at home, and overnight, consider washable, reusable organic cotton pads.

Here’s one small bright side: One study found that because these products accumulate in our blood, menstruators may actually have slightly lower levels of PFAS during our menstruating years than non-menstruating people, because we’re eliminating a small amount with each period. That’s one fun fact to think about when you’re changing that next menstrual product! 

We Need Systemic Change Now to Address Forever Chemicals

Sadly, we will not be rid of PFAS on this planet any time soon, certainly not in our own lifetimes, but production can – and should – be phased out. Many companies have done so in recent decades, and we do see rates of PFAS in humans decrease when exposure declines. The onus shouldn’t be on individuals to attempt the impossible task of reducing their own personal exposure by policing every product they purchase, their water, even their household dust.

As we’ve seen, there’s a lot we don’t know yet. We certainly need more and better research into the health effects of PFAS generally and into the risks posed by toxins in menstrual products. But one of the most important tenets of environmental health is the precautionary principle: decision-makers should adopt precautionary measures when scientific evidence about an environmental or human health hazard is uncertain and the stakes are high. Even if there is some uncertainty about levels of harm, there’s enough data to strongly suggest that PFAS has a negative impact on multiple aspects of human – and women’s – health. We need preventative action taken. 

We need our government agencies to do a better job regulating industry – and not just when it comes to our water, which has been the main priority – but far beyond that. The FDA and EPA must require more of product companies in terms of product testing and transparency. We need a full list of ingredients on all menstrual products so that we can be the informed consumers we try to be. We deserve to have accurate information to implement our choices and decide what we do – and don’t – want in and on our bodies. 

It can be done: In 2019, New York became the first state to require that all menstrual products sold in the state disclose all intentionally added ingredients. A similar law went into effect in California at the beginning of the year, though advocates say that, by allowing some exceptions, it doesn’t go far enough in giving consumers full transparency. Plus, even those laws wouldn’t necessarily help in cases  like Thinx – they maintain that they didn’t intentionally add PFAS to their products. 

I’ll continue to bring you information on and deep dives into EDCs and specific health concerns in upcoming articles/episodes. Our personal and planetary health depends on us making the best choices possible – and we can’t ignore it and hope this problem will go away. It won’t. But take this away with you: we can reduce our exposure and advocate for change in our homes, communities, and local governments. Until all products on the market are body-friendly and planet-friendly,  find and use those products that do meet the standards you want for your personal, hormonal, reproductive, intergenerational, and planetary health, and make sure to pass this information along. Women’s consumer spending power can and does pave the way for much-needed policy change.