Is Your Dental Floss Full of Forever Chemicals?

Floss feels like the least controversial product in your bathroom, until you read the label. In 2019, researchers found that women who regularly used a popular "glide"-style dental floss had measurably higher levels of a PFAS chemical in their blood than women who didn't. If that's the first you're hearing of it, you're not alone, and it's worth five minutes to understand what's actually going on.

This guide covers what PFAS are, what the actual research found (and didn't find), how to check any floss for it, and PFAS free alternatives, including where our own bamboo charcoal floss stands.

What Are PFAS, and Why Are They in Floss?

PFAS (per- and polyfluoroalkyl substances) are a family of thousands of synthetic chemicals prized for making things slippery, waterproof, and stain resistant, think non-stick pans, waterproof jackets, and stain resistant carpet. They're nicknamed "forever chemicals" because their carbon fluorine bonds barely break down, so they persist in the environment and in the human body for years.

In dental floss, the relevant PFAS is usually PTFE (polytetrafluoroethylene), the same polymer family as Teflon, used as a single smooth filament or coating to make floss glide easily between tight teeth without shredding. It's genuinely effective at that job, which is exactly why "glide," "silk-like," or "ultra-smooth" floss claims are worth a second look at the ingredients.

What the Research Actually Found

The most-cited study here is a 2019 analysis by scientists at the Silent Spring Institute and the Public Health Institute. They measured 11 PFAS chemicals in blood samples from 178 middle-aged women and asked about their habits, including floss brand. Women who regularly used Oral-B Glide floss had higher blood levels of a specific PFAS called PFHxS (perfluorohexane sulfonic acid) than women who used other flosses. The same research group separately tested floss products for fluorine (an indicator of PTFE) and found it in several "glide"-style products.

A few important caveats worth being upfront about:

• This was an association found in a cross-sectional study of 178 women, it shows a correlation, not proof that floss alone caused elevated PFAS levels. People are exposed to PFAS through many sources (drinking water, food packaging, stain resistant fabrics), and floss is one possible contributor among several.
• A more recent (2025) cross sectional study published in the Journal of Clinical Periodontology also found an association between PFAS serum levels and dental floss use, describing it as a "double edged sword", floss is essential for gum health, but material choice matters.
• The findings were significant enough that Oral-B reformulated its Glide floss to remove PTFE following the coverage, which is a meaningful real world response even though it wasn't a regulatory recall.

None of this means flossing is dangerous, skipping floss is worse for your gums than almost any material concern. It means the type of floss you use is worth a five second label check.

How to Tell If Your Floss Contains PFAS

• Look for "PTFE" or "Teflon" on the ingredients or packaging. This is the most direct giveaway.
• Be skeptical of "glide," "ultra-slide," or "shred-resistant" claims on unlabeled floss, that slipperiness is often (though not always) achieved with a PTFE coating rather than wax.
• Wax ≠ PTFE. Traditional wax coatings (beeswax or plant-based wax like candelilla) are a completely different, PFAS free way to make floss glide. Waxed nylon, waxed silk, and wax coated bamboo charcoal floss are not PTFE flosses.
• When in doubt, contact the brand. Ingredient transparency varies a lot by manufacturer, and a quick email or DM will usually get you a straight answer.

PFAS Free Floss Alternatives

The good news: PFAS free floss that still performs well is widely available. The main filament types are:

• Nylon — the classic multifilament floss, plastic but PFAS free, effective at plaque removal.
• Silk — biodegradable, gentle, usually wax-coated, but not vegan.
• Corn based PLA — plant-based, compostable under the right conditions, typically vegan.
• Bamboo charcoal blends — usually a polyester or nylon filament infused with charcoal, coated in plant wax rather than PTFE.

We cover the trade offs between these in detail, cleaning effectiveness, comfort, and environmental footprint, in our full guide to dental floss types.

Where Crescent Nest's Floss Fits

Our Bamboo Charcoal Dental Floss uses a polyester filament infused with bamboo charcoal, coated with candelilla plant wax and natural mint oil, no PTFE, no Teflon-style coating, no PFAS. We're upfront that the filament itself isn't biodegradable (it's still a plastic core), but it's genuinely PFAS free, and it comes in a refillable glass jar so you're not buying a new plastic dispenser every time you run out. You can browse the full dental floss collection here.

If you're building out a full routine, pair it with proper technique, our guide on whether to floss before or after brushing covers the order that actually matters.

FAQs

Does all dental floss contain PFAS?
No. PFAS (specifically PTFE) shows up mainly in "glide" or ultra smooth style flosses. Nylon, silk, PLA, and wax-coated bamboo-charcoal flosses are typically PFAS free.

Is Oral-B Glide still made with PTFE?
Oral-B reformulated its Glide floss to remove PTFE following the 2019 research and subsequent media coverage. If you're concerned, check the current ingredient list or contact the manufacturer directly, since formulations can change.

What is PTFE floss?
PTFE (polytetrafluoroethylene) is a synthetic fluoropolymer, part of the PFAS family and the same material used in non-stick cookware, used to make floss glide smoothly through tight teeth without shredding.

Is PFAS-free floss as effective as PTFE floss?
Yes, when used correctly. PTFE floss slides more easily, but that same slipperiness can mean it glides over plaque rather than scrubbing it off, so it sometimes needs extra passes. Textured PFAS-free flosses like nylon or bamboo charcoal can be just as effective at plaque removal.

Should I be worried about past PFAS exposure from floss?
A single source of past exposure isn't something to panic over, PFAS come from many everyday sources, and switching floss going forward is a reasonable, low effort step. If you have specific health concerns, talk to your doctor.

This article summarizes publicly available research for general information and isn't medical advice. If you have concerns about PFAS exposure, speak with your healthcare provider.