Toxins & Microplastics in Dental Floss
- Alayne
- Sep 22, 2025
- 6 min read
Updated: Apr 29
Not Flossy: Toxic Materials & Ingredients in Dental Floss | Low Tox Swap
THE THREADS
Most big-name brands of dental floss are made from nylon (a petroleum-based synthetic polymer), polyester (a petroleum-based synthetic fiber), or PTFE (a fossil fuel derived synthetic fluoropolymer). PTFE floss typically has a flat, ribbon-like design and is touted as being stronger with the ability to 'glide' easily between teeth. A popular, more familiar brand name for PTFE is Teflon. Warnings about Teflon-coated cookware have circulated for some time, so why the radio silence when PTFE is in a product that we run through our teeth?
MICROPLASTICS
Nylon, polyester, and PTFE are thermoplastics. Dental floss made from thermoplastics release microplastics if they become shredded during use. Friction from flossing also causes plastic particles to shed into the mouth. The particles are collected in saliva and subsequently swallowed. Ingested microplastics and the chemicals they carry enter the bloodstream and circulate to organs like the heart, liver, spleen, and brain. Chemicals and microplastics can also gain direct access to the bloodstream if gum damage or bleeding is encountered while flossing.
CHEMICALS
Chemical coatings like PFAS, forever chemicals, add to the pile-on of toxins in dental floss. A Consumer Reports investigation conducted in 2024 discovered concerning levels of PFAS in several popular dental floss brands. Additionally, be wary of synthetic fragrances, synthetic flavorings, and waxes derived from petroleum as they contribute to the chemicals that can be absorbed during flossing.
In This Post:
Toxins & Microplastics in Dental Floss | Low-Tox Flossing | Low-Tox Alternative | 'Clean' Branding Hype
Toxins & Microplastics in Dental Floss
Microcrystalline Wax
Petroleum-based synthetic wax that may contain impurities like PAHs, known carcinogens, and toxins like 1,4-dioxane, a known carcinogen that also causes numerous health conditions like reproductive harm, liver and kidney damage, and nervous system damage. Flammable. Not biodegradable. Harmful to aquatic life.
Nylon
Fossil-fuel based thermoplastic derived from petroleum. One of the most common materials used in conventional dental floss. Capable of shedding microplastics and nanoplastics as a result of the friction that is created against teeth during flossing. Made of twisted strands, it is prone to shredding which also causes microplastics to be released. Not biodegradable.
PFAS (per- and polyfluoroalkyl substances)
A large, complex group of synthetic chemicals. Referred to as forever chemicals because of their persistence in human bodies and the environment. Studies have revealed that exposure to these chemicals can lead to hormone disruption, adverse reproductive and developmental outcomes, liver damage, cardiovascular issues, weakened immune function, altered thyroid function, lipid and insulin dysregulation, and an increased risk of certain cancers. Not biodegradable.
Polyester aka PET (polyethylene terephthalate)
Synthetic fiber derived from petroleum-based chemicals. Identified as an endocrine disruptor that alters developmental and reproductive health. Polyester is a fiber version of PET, both classified thermoplastics that release microplastics and nanoplastics during flossing. Can be associated with PFAS and synthetic, petroleum-based wax (microcrystalline wax) coatings. Not biodegradable.
PP (polypropylene)
Predominantly petroleum-based thermoplastic which, like its counterparts PET and nylon, releases microplastics and nanoplastics during flossing. A by-product of refining crude oil and natural gas. Can be associated with PFAS and synthetic, petroleum-based wax (microcrystalline wax) coatings. Not biodegradable and persists for hundreds of years in the environment contributing to plastic pollution.
PTFE (polytetrafluoroethylene)
Synthetic thermoplastic fluoropolymer derived from fossil fuel. Capable of shedding microplastics during flossing. PTFE is a type of PFAS, but it is not considered as harmful due to its larger molecular size which prevents it from being as easily absorbed by the human body. Can be associated with PFAS and synthetic, petroleum-based wax (microcrystalline wax) coatings. Not biodegradable.
Is Dental Floss Made from PLA Safe?
PLA (polylactic acid)
Plant-based thermoplastic also referred to as a bioplastic. Derived from corn, sugarcane, and sugar beets. Considered a safer, more eco-friendly option than petroleum-based plastics, but there are some concerns that PLA may only be biodegradable in industrial composting facilities (at high temperatures and in specific conditions), not in soil, home compost, or landfill environments indicating that more research and considerations are needed to fully understand its broader environmental effects. With synthetic plastics and microplastics persisting for centuries, PLA is a more viable option.
Low-Tox Flossing
NATURAL SOURCES
Look for natural alternatives like silk, bamboo, or plant-based materials that are plastic-free. Select brands that come in refillable or recyclable glass jars, metal tins, or paper boxes.
NATURAL COATINGS
To avoid PFAS in your dental floss, choose brands that clearly state they are PFAS-free or are completely natural. Switching to a PFAS-free alternative or selecting a brand that uses natural materials and is coated with natural waxes like beeswax, coconut oil, or candelilla wax will limit your exposure to this harmful group of chemicals.
Low-Tox Dental Floss Swap: Canary
STRONG ENOUGH?
I've had trouble with natural flosses shredding or breaking between tight contacts (where two teeth touch). For my latest trial, I turned to the brand that makes the toothpaste tablets that I use and adore. Allow me to introduce you... meet Canary floss. I didn't try it right away because I wasn't sure about the inconclusive concerns about the biodegradability of PLA. My household isn't plastic-free (mindful in making changes, but honest with myself), so I needed to be realistic here. In spite of it being made from PLA, in this case, corn-based with added activated charcoal (not nefarious petroleum-based plastic), it will stay in my routine because it is super strong. This little bundle of thread is a beast.
CANARY STATS
Canary is priced well for a natural floss, where some brands marketed as clean (but aren't) cost almost twice as much for the same length. Canary is the best floss I've used thus far... natural and toxic alike. Its coating is natural candelilla wax, and it's free of plastic and all of the other chemicals covered in this post. Its packaging is recyclable, and it holds 30m (98ft) of floss. It lasts longer for me than a conventional brand that is 50m. Canary designates a single pack as a 1-month supply, flossing 2x per day using 12-18" of floss per use. My frugal self uses about 9-10" of floss so I get almost 2-months out of a single.
PLA & CHARCOAL
Canary Charcoal Mint Dental Floss contains PLA and charcoal, neither of which are toxins, but as we covered earlier, there are some concerns around PLA not breaking down well in the environment and charcoal may be slightly abrasive on enamel. I will continue to investigate silk and bamboo options and report back if and when I find a favorite. In the meantime, I'll stay friends with my little powerhouse, Canary.
Orders placed via Collaboration Links attribute commissions at no expense to you.
As an Amazon Associate, I earn from qualifying purchases via Amazon links.
Canary Dental Floss
Vegan/Gluten-free
No Microplastics, PFAS, Parabens, Sulfates, Aspartame
Wyld25
25% off all orders
Free shipping over $35
Excellent customer service and timely shipping
or
Canary's Low-Tox Personal & Homecare Products:
Nano Hydroxyapatite Toothpaste Tablets
Foaming Hand Soap
Bar Soap
Clay Face Masks
Plastic-free Bamboo Toothbrushes
Alcohol-free Mouthwash
Watch Out for Greenwashing & 'Clean' Dental Floss Branding Hype
KEEKO
Be vigilant when seeking a natural dental floss brand. I failed to recognize what now seems to be somewhat of an advertising smokescreen by Keeko. I got lost in the hype that it was made from bean wax, coconut oil, and natural coconut flavor. The formula was vegan, cruelty-free, free of beeswax, mineral oil, phthalates, and parabens, which are all great attributes. Unfortunately, it left a greasy mouthfeel and shredded very easily leaving strands of floss wedged between teeth. I went back to investigate a little further to be sure I didn't choose a new brand made of the same materials. Oh my... the floss was nylon. I prefer recommending effective low-tox options as opposed to throwing not-so-clean brands to the wolves, but to spare you of making the same mistake, I'm sharing the brand names with you.
COCOFLOSS
Another brand that comes out of the gate marketing their safe ingredients is Cocofloss. It looks trendy, it has a price tag that separates it as an elite version of floss, it's free of PTFE, PFAS, parabens, sulfates... and... it's polyester (so it's plastic). Beyond having plastic thread, it's synthetically flavored, coated with microcrystalline wax, and packaged in plastic.
REACH POP
Reach Pop is a more mainstream brand that markets itself as stylish and PFAS-free with 384 interlaced micro-threads and a vegan wax coating, but what is not stated outright is that the floss is nylon with ambiguously listed bright 'colors' and 'flavors'. It's packaged in 100% RPET recycled plastic, which is more eco-friendly, but it's still plastic, just like the floss.
To brush up on your low-tox dental care, visit my Canary Toothpaste Review and Toxins in Traditional Toothpaste & Natural Toothpaste posts.
Comments