Most dental floss is not toxic, but some brands contain chemicals worth knowing about. The main concern is a group of synthetic compounds called PFAS, sometimes called “forever chemicals,” which are used to make certain flosses glide more easily between teeth. Testing of 39 floss brands found PFAS in roughly one-third of samples, with concentrations ranging from 11 parts per million to nearly 25 percent of the product’s composition.
The PFAS Problem in Dental Floss
PFAS are a family of nearly 12,000 chemicals used to make products slippery and water-resistant. They’re the same compounds behind nonstick cookware coatings. In dental floss, PFAS (specifically a type called PTFE) create that ultra-smooth, glide-style texture that slides between tight contacts without shredding.
Testing by the consumer wellness site Mamavation and Environmental Health News found wide variation across products. Four brands exceeded 70,000 parts per million (7 percent PFAS by weight), and Oral-B Glide tested at 248,900 ppm, meaning roughly a quarter of the product was PFAS material. Many other flosses tested at negligible levels or showed no detectable PFAS at all. The pattern is clear: if a floss feels slick like tape rather than fibrous like thread, it’s more likely to contain PTFE.
Does Flossing Raise PFAS Levels in Your Body?
This is where the picture gets complicated. A study of 178 middle-aged American women found that those who used Oral-B Glide had higher blood levels of one specific PFAS compound called PFHxS. A larger cross-sectional study of U.S. adults found that floss users overall had slightly elevated blood levels of another compound, PFOA, compared to non-users. That difference was statistically significant.
However, the same large study found something counterintuitive: floss users actually had lower blood levels of four other PFAS compounds and a lower overall PFAS burden score than people who didn’t floss at all. People who floss regularly tend to have different lifestyle habits across the board, which makes it difficult to isolate flossing as the sole source of any one chemical. PFAS exposure comes from dozens of everyday sources, including drinking water, food packaging, clothing, and cookware.
The practical takeaway is that PFAS-containing floss likely contributes a small, measurable amount of specific compounds, but it doesn’t appear to be a major driver of total PFAS exposure for most people.
What Regulators Say
The American Dental Association reviewed the research linking floss to PFAS exposure and found the data insufficient to support restricting any floss products. The ADA noted that PTFE is widely used in food, pharmaceutical, and cosmetic applications, and that detecting PTFE in floss doesn’t prove it’s responsible for elevated blood levels of specific chemicals. The FDA has not issued any restrictions on PFAS in dental floss.
Europe is moving faster. The EU is pursuing a broad restriction proposal on all non-essential uses of PFAS, and consumer testing in 2025 specifically flagged dental floss as a product category of concern. All PFAS in food contact materials will be restricted in the EU starting in 2026, and further bans on PFAS in health and hygiene products are expected.
Microplastics Are a Separate Concern
Beyond PFAS, conventional floss is typically made from nylon or polyester, both of which are plastics. Research examining microplastics in oral healthcare products found four major polymer types across products including dental floss, with polyethylene and polyamide (nylon) being the most common. When you pull floss between your teeth, small fibers can shred and break off, potentially releasing microplastic particles that you swallow. The health significance of ingesting tiny amounts of microplastic from floss is still poorly understood, but it’s a concern that has driven interest in non-synthetic alternatives.
How to Choose a Safer Floss
If you want to minimize chemical exposure from floss, the simplest rule is to avoid anything marketed as “glide” or described as tape-style floss. These products are far more likely to be made from PTFE. Traditional woven or braided flosses made from nylon contain no PFAS, though they are still synthetic.
For the lowest chemical footprint, natural flosses exist made from silk coated in beeswax with plant-based mint flavoring. These contain no synthetic polymers and no PFAS. The tradeoff is that silk floss tends to be less durable, can shred more easily between tight teeth, and costs more than conventional options. It also isn’t vegan, if that matters to you.
The most important thing is that you keep flossing. Skipping floss entirely to avoid trace chemical exposure would be a poor trade, since gum disease is linked to heart disease, diabetes complications, and tooth loss. If PFAS-free options feel comfortable and clean effectively between your teeth, they’re a reasonable swap. If glide-style floss is the only kind you’ll actually use daily, the benefit of removing plaque and bacteria still far outweighs the small chemical exposure involved.