The People's Perspective on Medicine

Does Your Dental Floss Contain PFAS Chemicals That Disrupt Hormones?

Dental floss treated to slide easily between the teeth may contain endocrine-disrupting chemicals called PFASs. Do they have health effects?
Woman looking in the bathroom mirror and using dental floss to clean her teeth. Reflection of woman in bathroom mirror while brushing teeth in morning.

How many times has your dentist told you to floss your teeth? Lots, right? But flossing can be a drag, especially if you use the unwaxed kind. It gets stuck or shreds. That’s why waxed or slippery floss is so popular. But a new study raises questions about the chemicals used to make dental floss and other substances slippery. PFAS stands for a tongue twister: polyfluoroalkyl substances. They’re found in lots of nonstick chemicals and they are suspected of causing substantial mischief, including thyroid problems.

PFAS Are Hard to Avoid:

There are a bunch of PFASs. They’re all impossible to pronounce. Here are just a few example:

PFOA (perfluorooctanoic acid)

PFOS (perfluorooctanesulfonic acid)

PFNA (perfluorononanoic acid)

PFHxS (perfluorohexanesulfonic acid)

PTFE (polytetrafluoroethylene)

These PFASs are used in all sorts of places you might not suspect. They are found in nonstick cookware and stain-repellent sprays. Carpets and furniture may be coated with PFAS to prevent stains from sticking to the fibers. Grease-resistant packaging may also have PFAS. Think pizza boxes or paper containers that hold French fries. Most surprising to us, though, was the report that suggested there are PFASs in some dental floss products (Journal of Exposure Science & Environmental Epidemiology, online, Jan. 8, 2019).

Why Should We Care About PFAS?

The authors of the article cited above state:

“Given their extensive use and persistent nature, it is unsurprising that PFASs have been detected in water and soil, and in the bodies of almost all Americans. Exposure to the long-chain PFASs perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) has been linked to kidney and testicular cancer, decreased semen quality, and ulcerative colitis in adults, and to thyroid disease, immune response, and lowered sex and growth hormones in children.”

PFAS and Thyroid Problems:

There appears to be a link between exposure to PFASs and thyroid disease. One chemical in particular, PFOA, has been associated with both hypo and hyperthyroidism. This was the conclusion of of the C8 Science Panel (July 30, 2012).  These scientists evaluated exposure of residents in Parkersburg, WV, to PFOA.

Ask veterinarians about the epidemic of hyperthyroidism in cats. It is a mystery, but there is tantalizing research to suggest that higher levels of PFASs in the environment could be associated with increasing amounts of feline hyperthyroidism (Wang, et al, Environmental Toxicology and Chemistry, Sept. 19, 2018). Another class of chemicals, PBDEs that are used as flame retardants, may also be contributing. If you are interested, here is a fascinating article by Emily Anthes in The New York Times (May 16, 2017) titled “The Mystery of the Wasting House-Cats.”

What About Dental Floss?

The article in the Journal of Exposure Science & Environmental Epidemiology (online, Jan. 8, 2019) describes blood levels of PFASs in 178 middle-aged women.

The investigators found:

“Flossing with Oral-B Glide was associated with higher levels of PFHxS. All three Glide products that we tested contained fluorine, consistent with available information that Oral-B Glide is made with PTFE and supporting our hypothesis that Oral-B Glide is a potential exposure source for PFASs. In addition, three other flosses also tested positive for fluorine, including two of three store-brand products advertised as ‘compare to Oral-B Glide’ on the package, and one described online as ‘single strand Teflon®fiber’.”

The researchers conclude:

“While this study did not capture all the potentially important sources of PFASs, our results strengthen the evidence for exposure to PFASs from food packaging and implicate exposure from PTFE-based dental floss for the first time—a finding that warrants prompt follow-up in a future study.”

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
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The only people who can successfully use POH have gaps between their teeth and probably no inlays/fillings either. My former dentist used to insist on it, and every day I would spend five minutes trying to remove shredded and torn floss that was stuck between my teeth. I finally ignored his fiat and switched to a waxed product. That was forty years ago.

My current dentist is ambivalent, and his hygienist has a bunch of POH horror stories.

Even if I were to switch to an “unwaxed” product, I would never go back to POH.


I’ve used the store-brand un-waxed dental TAPE for years. Tape is wider, a bit stronger, and does a more thorough job of removing food bits from between my teeth. Thanks to an article I read here on The Peoples’ Pharmacy, I now floss before I brush; my teeth feel cleaner.

After having read People’s Pharmacy for nearly two years, I have become a Jain. I sit naked in a temple fasting and using a fan to prevent imbibing unseen creatures. The only thing I read are People’s Pharmacy downloads with their daily declarations of pervasive toxicity and carcinogens,

I would appreciate some advice about how to avoid this in dental floss. Is there any product on the market that would be safer to use?

RADIUS – Natural Biodegradable Silk Floss is coated with calendula wax. I love it.

I buy “Eco•Dent VeganFloss” at my local health food store. “100% vegan waxed with all-natural essentials oils” the label says.

Just when I thought I’d guarded against every chemical that might worsen my fibromyalgia pain, we have hormone disruption by dental floss, used religiously by all of us in First World countries. Unbelievable, is nothing safe? Will sellers use anything, with known or unknown risks, to make a profit? Don’t their families use floss?

While perfloro acids have been linked to health problems, polytetraluroethylene (PTFA) has not UNLESS it is heated to high temperature (ie cooking) where it can break down to release degradation products like perfloro acids or is contaminated with those compounds during manufacture. Testing the dental flossing agents for fluorine is meaningless as that test is not specific enough. Those products need to be tested for the problematic prefluoro acids – only then can we know whether there is a health issue from the presence of those compounds.

My dentist has me using an oral product that is supposed to build up my enamel. I believe it contains fluorine as well. And I recently changed to Oral B floss because I was sick and tired of the other brand getting caught and tearing on my numerous crowns.

Eco brand of dental floshas no PFAs.. It’s also in a cardboard container instead of a plastic one.
Order it from or Swanson.

Thank you for sharing that useful information on a safe product!

Thanks for letting us know about Eco dental floss. I just ordered some.

Is there anything on the packaging of dental flosses that we can look for to check if they have these harmful substances? What should we look for since floss doesn’t have the nutrition or information panel that many foods and other products have?

The flossers I use say they have “shred resistant nylon mint floss.” How do I find out if they have PFAs?

For years, I have flossed with unwaxed, buying on-line from POH. Because it is unwaxed, it allows me to scrape the surface of the tooth, and it’s easier to floss under the gum line. The major commercial brands of unwaxed floss are inferior, in my view.

Where do you get POH???

Is any dental floss safe????? I have 30 new containers of Oral B Glide floss I bought at Costco and I just put them in the trash to be recycled. They maybe too toxic to recycle.
I stopped using supplements because they are toxic, I have still have to take Valsartan that causes cancer, and now I have to stop using dental floss.

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