Every morning, without thinking about it, you pick up your toothbrush, squeeze on some toothpaste, and spend two minutes doing something you've been told your whole life is good for you.
And it is good for you. Brushing your teeth is one of the most important things you can do for your health. But there's something happening during those two minutes that nobody told you about. Something that's been confirmed by multiple peer-reviewed studies, and that the $8.5 billion toothbrush industry has absolutely no interest in talking about.
Your toothbrush bristles are shedding tiny plastic particles. And you're swallowing them.
Not occasionally. Not in trace amounts. Every single time you brush.
This isn't a fringe theory or a wellness influencer's hot take. It's published science. And once you understand what's actually happening inside your mouth every morning, you won't be able to look at your toothbrush the same way again.
What the Research Actually Says
In 2024, a study published in the Microchemical Journal set out to quantify exactly how many microplastic particles are released during a standard brushing session. Researchers used a 3D-modelled dental arch and simulated twice-daily brushing over seven days under realistic conditions.
The result: every toothbrush tested released microplastics. Every single brand. No exceptions.
The average was approximately 39 microplastic particles released per day. Some estimates from other studies put the number higher — between 30 and 120 particles per brushing session depending on the brand, bristle type, and brushing force.
Think about that number for a moment. 39 particles a day. 273 a week. Over 14,000 a year. Every year of your life that you've been brushing with a standard nylon toothbrush.
The particles don't just sit in your mouth. They get mixed into your saliva, swallowed with your toothpaste, and absorbed through the mucous membranes in your mouth — one of the most permeable surfaces in the human body.
What Are Toothbrush Bristles Actually Made Of?
Here's where most people are surprised.
The bristles on your standard toothbrush — even the expensive ones, even the "soft" ones, even the ones from brands that market themselves as premium — are almost universally made from nylon. Specifically, a type of synthetic polymer called polybutylene terephthalate (PBT) or standard nylon-6,6.
These are petroleum-derived plastics. The same family of materials used to make plastic bottles, synthetic clothing, and packaging.
Standard toothbrush bristles under magnification — petroleum-derived nylon.
When these bristles flex back and forth against your teeth and gums — which is exactly what they're designed to do — they experience mechanical stress. They bend. They rub. And at a microscopic level, tiny fragments break off. Fragments small enough to pass through biological barriers. Fragments that researchers classify as microplastics.
This isn't a manufacturing defect. It isn't the result of a bad batch. It's simply what happens when you rub plastic against hard surfaces repeatedly, twice a day, every day.
Why This Matters More Than You Might Think
Microplastics are not inert. That's the key thing to understand.
For a long time, the assumption was that if a substance passed through the body without being digested, it wasn't really a problem. We now know this isn't true for microplastics.
Research is showing that microplastic particles can:
- Cross biological barriers — Microplastics small enough (under 150 micrometres) have been shown in studies to pass through the gut lining and enter the bloodstream. Once in circulation, they can travel to organs.
- Carry chemical additives — Plastics don't exist in a pure state. They contain plasticisers, colourants, stabilisers, and other chemical additives that were used during manufacturing. When microplastics enter the body, these chemicals can leach out into surrounding tissue.
- Accumulate over time — Unlike water-soluble substances, microplastics don't flush out easily. Studies have now detected microplastics in human blood, lung tissue, liver tissue, and most recently, in the human heart. They build up.
- Trigger inflammatory responses — Particles the immune system doesn't recognise can provoke low-grade inflammatory responses. Chronic low-grade inflammation is a known driver of a wide range of modern health conditions.
It's worth being clear: the science on long-term human health effects is still developing. Researchers are careful not to overclaim. But the trajectory of the evidence is consistent, and it points in one direction: less plastic exposure is better, and the mouth — where microplastics are introduced directly into your body twice daily — is not a good place to start.
"But Isn't It Just a Tiny Amount?"
This is the most common response, and it's a fair one to examine honestly.
Yes, 39 microplastics a day sounds small. But consider the context.
You are also ingesting microplastics from tap water, from food packaging, from the air you breathe, from synthetic clothing, and from dozens of other daily sources. Researchers estimate the average person ingests roughly 5 grams of microplastic per week — the equivalent of a credit card's worth of plastic entering your body every seven days. (More on the wider exposure picture in our breakdown of why your bathroom is the most chemically loaded room in your home.)
The toothbrush is not the only source. But it is one of the most direct. Unlike microplastics in your food, which at least have to survive stomach acid and the full digestive process, the particles released by your toothbrush are introduced directly into the most absorbent part of your body — your mouth — and immediately mixed into what you swallow.
When you're already being exposed from multiple directions, removing one of the most direct sources isn't a small thing. It's one of the highest-leverage swaps you can make.
What About "Eco" Bamboo Toothbrushes?
This is important, because a lot of people make the switch to bamboo and assume they've solved the problem.
They haven't. Not fully.
The handle of a bamboo toothbrush is made from bamboo — genuinely sustainable, genuinely biodegradable, genuinely plastic-free. But the bristles? In the vast majority of bamboo toothbrushes on the market, the bristles are still made from nylon.
The same petroleum-derived plastic. The same shedding behaviour. The same microplastic release.
Some brands have started using "plant-based" bristles — typically made from bioplastics derived from castor oil or corn starch. These are marketed as a more natural alternative, and the handle material is certainly an improvement. But here's what the research shows: bioplastics can still shed microplastics. A 2023 study published in the Journal of Hazardous Materials confirmed that PLA bioplastics — one of the most common plant-based plastic alternatives — still release microplastic particles under mechanical stress.
The handle being bamboo doesn't change what's happening at the tip of the bristles, inside your mouth.
The Only Bristle That's Actually Different
There is one type of bristle that sidesteps this problem entirely — not by using a different kind of plastic, but by using no plastic at all.
Natural horsehair bristles have been used for centuries. Before nylon was invented in the 1930s and quickly adopted by the dental industry for its cheapness and consistency, natural bristles were the standard. (For the full head-to-head, see horsehair vs nylon: the honest comparison.)
Horsehair bristles are:
- 100% natural — derived from horse mane and tail hair, a byproduct of the equine industry, collected humanely without harm to the animal
- Fully biodegradable and compostable — when you're done with the brush, every part of it can return to the earth (more on what fully biodegradable actually means)
- Genuinely soft — horsehair is naturally softer than nylon, making it particularly good for people with sensitive gums
- Free from plastic additives — no synthetic dyes, no chemical stabilisers, no petroleum derivatives
- Non-shedding in the way nylon sheds — when a natural hair bristle wears, it degrades into organic material, not synthetic polymer fragments
How to Make the Switch
If you're reading this and thinking "okay, I want to change" — the good news is that this is one of the easiest swaps you'll ever make.
A few things to know when switching to a natural bristle toothbrush:
- They feel different at first. Natural bristles have a slightly different texture to nylon — softer, more flexible. Most people find this an upgrade, especially if they have sensitive gums. Run the bristles briefly under warm water before your first use to soften them.
- They need to dry properly. Natural hair absorbs a small amount of moisture. Store your brush upright in a ventilated area — not in a closed cup or damp travel case. This is why KYND brushes are designed to stand upright on their own.
- Replace every 2–3 months. Same as a standard toothbrush.
- Composting is actually possible. When your KYND toothbrush reaches the end of its life, the entire thing — bamboo handle, horsehair bristles and even the kraft packaging box — can go into your compost. No landfill. No plastic fragment left behind.
A few things set KYND apart from other natural toothbrushes worth knowing about. The bamboo handle is coated in 100% natural beeswax — no synthetic lacquers, no chemical coatings of any kind. The beeswax seals the bamboo naturally, preventing moisture absorption and mold while keeping the handle completely plastic-free. The brush is also designed to stand upright on its own without a holder — a deliberate hygiene feature that allows the horsehair bristles to air dry completely between uses, eliminating the moisture that causes bacterial growth. And the packaging itself — kraft cardboard, no plastic windows, no lamination — is fully home compostable. When your KYND order arrives, nothing in the box needs to go to landfill. Not the brush, not the packaging, not a single component.
A Small Switch. A Real Difference.
We're not asking you to overhaul your life. We're not telling you that your toothbrush is going to kill you. The science on long-term health effects is still developing, and we'd rather be honest with you about that than sensationalise it.
What we are saying is this: you brush your teeth twice a day, every day, for your entire life. That's a lot of repetition. And when one of those daily repetitions is introducing plastic particles directly into your body — when there's a straightforward, affordable, genuinely better alternative — it seems like a reasonable thing to change.
Ready to make the switch? KYND's natural horsehair bamboo toothbrush 4-pack is available at trykynd.co. Every bristle natural. Every part compostable.
References
- Azoulay, D. et al. (2024). Preliminary results on microplastic release from commercial toothbrushes during simulated brushing. Microchemical Journal. sciencedirect.com
- Aragaw, T.A. (2023). Microplastic release from bioplastic (PLA) materials. Journal of Hazardous Materials.
- Leslie, H.A. et al. (2022). Discovery and quantification of plastic particle pollution in human blood. Environment International. sciencedirect.com
- Prata, J.C. et al. (2020). Environmental exposure to microplastics: An overview on possible human health effects. Science of the Total Environment.
- WWF (2019). Revealed: plastic ingestion by people could be equating to a credit card a week. wwf.org.au