Which toothbrush bristles shed microplastics? The materials compared

The bristle materials, side by side

Most of the confusion comes from labels that name a raw material or a handle instead of the bristle itself. Pick a material to see what it actually is, and what’s known about it. Each one links to the guide that goes into it properly.

Two words you’ll see on packs aren’t bristle materials, so they aren’t in the picker. “Charcoal” describes a pigment, so check the filament underneath it; we cover that in are charcoal toothbrushes worth it? And “corn starch” usually means a bioplastic such as PLA, which the NSW EPA counts as a plastic. More in are corn starch toothbrushes compostable?

What the shedding research has found

Research on toothbrush shedding is new, and there isn’t much of it. A 2023 study used Raman imaging to confirm that toothbrushes release microplastics in use. A 2025 lab study, which its authors call preliminary, simulated brushing on a dental arch with commercial brushes and identified PBT and nylon among the particles released. The brushes it tested released an average of up to about 39 particles a day. That is the top of its range, not a typical brush.

Those are the two bristle plastics a study we could check has found. We looked for the same kind of measurement on castor oil nylon and on silicone bristles and didn’t find one. That is a gap in the research, not evidence that they don’t shed.

You’ll also see much bigger numbers per brushing on brand blogs. We couldn’t trace them to a study we could check, so we don’t use them. There’s more on the evidence in do toothbrushes shed microplastics?

A plant-based nylon is still a nylon

Castor oil is a raw material, not a fibre. Through several chemical steps it becomes nylon 11, and it can also supply a building block of nylon 610 and 1010. The plant decides where the raw material came from. It doesn’t change what the finished bristle is, or that what wears off it is still plastic.

Bio-based isn’t the same as biodegradable either. The European Commission notes that bio-based plastics are not necessarily biodegradable or compostable, and researchers describe nylon 11 as a plastic that has previously been considered non-biodegradable.

We wouldn’t assume a nylon made from a plant wears differently from any other nylon. A pack that says castor oil bristles shed less would need a test behind it, and we haven’t seen one.

Bamboo is the handle, not the bristle

Bamboo toothbrushes come up in this question a lot. On a bamboo toothbrush the bamboo is the handle, and nylon is the most common bristle choice for bamboo toothbrushes. So most bamboo brushes wear and shed from the head the same way a plastic brush does. The handle is the part you see. The bristles decide the answer, which is why we wrote are bamboo toothbrush bristles plastic?

Silicone sits in between

Silicone is a synthetic polymer with a silicon and oxygen backbone. EU food-contact law keeps silicones separate from plastics, while other definitions are less clear, so whether it counts as plastic depends on whose definition you use. Cured silicone rubber is described as difficult to degrade naturally. We go through it in are silicone toothbrushes plastic-free?

What isn’t plastic

Horse hair and boar bristle are animal hair. Both are keratin, the protein family that also makes wool, and microorganisms in soil and water break keratin down with enzymes called keratinases, though keratin is tough and slow to go. Whatever wears off a hair bristle is hair. The miswak stick skips bristles altogether: it’s a twig you chew into fibres.

Natural bristle has honest costs, and they belong next to the good news. It isn’t vegan. Hair takes up water and swells, where nylon takes up less. And nylon has a real advantage at the tip. A 1982 microscope study found new swine and wild boar bristles had irregular, uneven ends while nylon’s were uniform, though horse hair wasn’t studied. Nylon tips can also be end-rounded, and a later trial of synthetic brushes found that ones with 40 to 50% or more of their filaments end-rounded caused fewer gum abrasions than ones simply cut. Natural bristle wasn’t part of that trial. The whole comparison is in natural vs nylon toothbrush bristles.

Should the shedding worry you?

Nobody knows yet. We haven’t found a study linking toothbrush microplastics to any health outcome, and the research that exists is small and new. Some people are comfortable with that and some would rather not run the experiment. Both are reasonable readings of the same evidence, and the longer version, with what’s proportionate to do, is in do toothbrushes shed microplastics?

Where we fit

We make a horse hair brush, so read this page knowing that. Our bristles are sterilised horse hair woven into the bamboo head, with no nylon and no glue.

Two honest catches. Ours isn’t vegan, because horse hair is an animal product. And there is one small aluminium staple inside the head, which doesn’t compost, so fish it out at the end. If vegan is your line, the vegan options in the table are plastic or silicone bristles, or the miswak. We wrote up the choices in is a bamboo toothbrush vegan?

The short version

• Any plastic bristle can shed as it wears. Nylon and PBT are the ones a published brushing study has found.
• Castor oil bristles are nylon from a plant raw material. We found no shedding study on them, and nylon 11 isn’t considered biodegradable.
• A bamboo handle changes nothing about the bristles, and most bamboo brushes use nylon.
• Horse hair and boar bristle aren’t plastic. They aren’t vegan either.