Toxic chemicals in period underwear? What to know as U.S.-based Thinx settles lawsuit

A U.S. company is facing growing backlash over concerns about toxic chemicals in its period underwear. Should women in Canada be concerned?

New York-based brand Thinx publicly confirmed last week that it had settled a US$5-million lawsuit that alleged the company had misled customers about its products being free of harmful chemicals.

The class-action lawsuit, which was filed last May, claimed that third-party lab testing found short-chain per- and polyfluoroalkyl substances (PFAS) in Thinx underwear.

Thinx has denied all allegations and wrongdoing in the case, saying “PFAS have never been a part of its product design.”

“Our customers’ health and safety remains our top priority,” Thinx said in a statement posted on Twitter Thursday. “We will continue to take measures to ensure that PFAS are not added to our products.”

According to the Thinx lawsuit settlement agreement, those who bought a pair of period underwear from the company between November 12, 2016 and Nov 28, 2022, can claim a US$7 refund per purchase for up to three pairs of underwear if they have the receipt. For those who don’t have proof of purchase, they will receive a US$3.50 cash refund per underwear for a maximum of three pairs.

Alternatively, customers also have the choice of getting a single-use voucher for 35 per cent off their next purchase.

The backlash against Thinx is not new – the issue was first brought to light in 2020 and adds to broader concerns about the safety of feminine hygiene products.

In Canada, Knix, which launched in 2013, also produces and sells period underwear.

Knix said it began routine testing for certain PFAS in its leak-proof fabrics and products in January 2020 when news broke about a potential link between period underwear and PFAS.

“At Knix we do not intentionally use PFAS in the manufacturing of our leakproof products,” the company said on its website in December 2021.

Knix also added that it takes steps to ensure that all of its third-party textile suppliers do not intentionally use PFAS in the fabrics they supply.

“In addition to organic fluorine testing, Knix also regularly tests its products for the most common PFAS,” the company said.

Aisle, another Canadian company that manufactures washable feminine hygiene products, reported last year that “no detectable levels of PFAS” have been found in its period underwear or menstrual pads, based on independent testing.

“All Aisle products are regularly tested by SGS – a leading testing and inspection company, to provide assurance as to whether PFAS are present in any fabric layers of our liners, pads, and underwear,” it wrote in a blog post.

However, it noted that is “technically impossible to say that anything is ‘PFAS-free,'” based on conversations with scientists.

PFAS are a group of thousands of long-lasting, human-made chemicals that are used in textiles, cosmetics, furniture, paints, firefighting foams, food packaging and other commonly used consumer products.

Known as “forever chemicals,” they are used as repellants for dirt, water and grease, which is why they are found in waterproof clothing and personal care products.

“Because of their widespread use and their persistence in the environment, many PFAS are found in the blood of people and animals all over the world and are present at low levels in a variety of food products and in the environment,” according to the U.S. Environmental Protection Agency (EPA).

Surveys conducted by the Centers for Disease Control and Prevention (CDC) show that most people in the United States have been exposed to some PFAS.

People are exposed to PFAS “mainly through food, drinking water and house dust,” Health Canada says on its website.

Meanwhile, hand-to-mouth contact with consumer textile products may be a “significant source of exposure” for infants, toddlers and children, the agency says.

While most known exposures to PFAS are relatively low, some can be high, especially when people are exposed to a concentrated source over long periods of time, the EPA says.

Some PFAS chemicals can also accumulate in the body over time, it added.

A number of studies have looked at the potential health hazards of exposure to PFAS, but more research is needed to fully understand the risks, experts say.

Exposure to certain PFAS is associated with reproductive, developmental, endocrine, liver, kidney and immunological effects, according to Health Canada.

“There is also weaker evidence linking them to other conditions, such as breast cancer, early onset puberty, and certain pregnancy complications, such as high blood pressure,” Canadian obstetrician and gynecologist Jen Gunter wrote in a blog post Sunday.

To lower human exposure, the government of Canada has prohibited certain types of PFAS, such as PFOS, PFOA, long-chain perfluorocarboxylic acids (LC-PFCAs), their salts and precursors.

Many women in Canada use period underwear, which like a menstrual pad absorbs the blood, but has the added advantage that it can be washed and reused.

So, is there reason to worry if you have worn period underwear possibly contaminated by PFAS?

“If you have been using Thinx, I wouldn’t panic,” said Gunter in her blog post.

While the vulva, the outer part of the female genitals, is more absorbent than other areas, most things placed on the vulva don’t absorb 100 per cent, according to Gunter.

“Overall, the biggest issue with PFAS in period underwear is likely the global contribution from manufacturing, washing, and then when it eventually ends up in landfill.”