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Silver and possible PFAS in 'organic' menstrual underwear has local women seeing red, so they sue

Women from Boston and Peabody say they never would have bought Thinx period underwear - or would have paid far less for it - if they had known it contained silver nano-particles and a possibly harmful class of chemicals known as PFAS, rather than being the 100% organic, safe alternative to tampons the company advertised it as.

Jillian Blenis of Boston and Lili Mitchell of Peabody are seeking to become lead plaintiffs in a class action against Thinx, Inc. of New York on behalf of all Massachusetts residents who have purchased the product, which users wear during their periods rather than using tampons or pads. A California woman filed a similar suit last fall.

In their suit, filed in US District Court in Boston, Blenis and Mitchell claim that the silver the company uses to kill bacteria and which the company says "won’t come off your undies" can, in fact, migrate to the users' vaginas, potentially disrupting the "vaginal microbiome" and causing potential health issues.

Also, the two say that after reading a 2020 article in Sierra, they sent samples of their underwear to a test lab, which found more than trace amounts of "short-chain PFAS." Manufacturers have phased out "long-chain" PFAS because of its toxicity and because it takes incredibly long to degrade, but continue to use the other form despite a 2019 study suggesting they can cause similar health issues. And because PFAS is man-made, any product containing it cannot legally be advertised as "organic."

According to their complaint, Blenis first purchased Thinx underwear in 2016 because she "was seeking an easy, safe, reusable, and sustainable form of menstrual protection." In 2019, after being diagnosed with endometriosis, she wanted to make sure she was only using organic menstrual protection, to guard against potential inflammation, and looked at Thinx's Web site:

These representations all indicated that that the Thinx Underwear was safe for normal use and fit for the purpose of collecting and/or absorbing menstrual fluid and other vaginal discharge, that the Underwear was sustainable and safe for the environment, and that the Underwear was free from harmful chemicals. The Thinx representations also stated the cotton underwear was organic, and Ms. Blenis relied upon that representation.

Ms. Blenis reasonably believed, based on Thinx’s representations, that the Underwear would serve as a safe, healthy, organic and chemical-free alternative to traditional menstrual products. Nothing in Thinx’s representations indicated to Ms. Blenis that the Underwear contained various chemicals known to be harmful to the female body and the environment.

The suit states that Mitchell bought her first pair of Thanx underwear in 2019, based in part on its ads on Facebook and Instagram and because she was "actively seeking an eco-friendly and chemical-free alternative to traditional feminine hygiene products."

In making her purchase, Ms. Mitchell specifically relied on Thinx’s representations on its website that the product was safe, free of harmful chemicals, and certified for ecological safety. Ms. Mitchell also relied on Thinx’s representations that stated the product was organic. Ms. Mitchell reasonably believed that all of the cotton used in the Organic Cotton Bikini and Organic Cotton Thong Underwear was organic.

After wearing the Underwear regularly, Ms. Mitchell experienced multiple infections, including bacterial vaginosis, a type of vaginal inflammation caused by the overgrowth of bacteria naturally found in the vagina. Bacterial vaginosis can occur when the vagina’s levels of lactobacilli are too low, causing other bacteria to grow.

Silver nanoparticles, like that contained within the Underwear, is known to disrupt lactobacilli in the vagina.

Nowhere on the Underwear’s label or packaging did Thinx disclose the presence of silver nanoparticles in its Underwear.

The two charge that Thinx violated Massachusetts consumer-protection laws through breach of warranty, unjust enrichment, negligent design and negligence in failing to warn consumers. They are seeking damages and an order forcing the company to "disgorge its ill-gotten gains," stop advertising the products as healthful and organic without making changes in it and attorneys' fees and court costs.

Complete complaint (2.8M PDF).
Similar California complaint (820k PDF).

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If the facts as asserted are correct, I hope that the lead plaintiffs and the attorneys, for taking on the work that the regulators were supposed to be doing, make some good coin.

Voting closed 57

regulators are always asleep when it comes to products that are inserted into or put near vaginas. no one cares about women's vaginas other than to want to force women to gestate any babies that are created in their vaginas. who the f&ck knows what's in tampons and pads, nothing good for us. hello toxic shock syndrome.

Voting closed 3

No different than the chemicals in the synthetics you are all wearing now on your stupid ass right now. Greatest thing about being menopausal is not having to deal with menstrual bullshit and being able to enjoy the new ability to tell everyone to fuck off and gettouttamyway!! It's not me it 's the hormones!!! Now excuse me while put my 100% natural hemp nightgown on.

Voting closed 19

nice try but i'm also menopausal and no one is going to out tantrum me in this comments section. my ass is swathed in cotton. enjoy your burlap sack/hair shirt.

Voting closed 22

Silver nitrate was mentioned in Prance Wear's 2013 patent. Thinx picked it up in 2016. The practice of misleading labeling spans many product categories, and fools countless consumers. This practice by marketing and ad teams needs to stop, but likely won't. It's also frustrating that consumers need to know how to do deep research on products, by referencing MSDSs, or even patents, to have a better idea of what they're actually purchasing.

Silver nitrate mentioned in SUMMARY [0009].

It is my hope that the plaintiffs win.

Voting closed 36

How is silver not organic?

Voting closed 20


Voting closed 23

Asbestos is organic.. but I can't buy it at whole foods because well... its Asbestos.

Voting closed 17

Asbestos in naturally occurring. It is, however, inorganic because it is not carbon based.

Silver is similarly naturally occurring, yet inorganic.


Voting closed 22

Fire retardant in underwear is something I would have expected to be required in the former president's administration. Not in mass-market period panties.

Voting closed 22