For most people, choosing a toothbrush comes down to three things: soft, medium, or hard. Maybe the brand. Maybe the colour.
Nobody ever told you that the material the bristles are made from was even a choice. Nobody suggested that "nylon" might not be the obvious answer. Nobody explained that for most of human history, people cleaned their teeth with something completely different — and arguably better.
This post is that conversation. An honest, side-by-side look at the two main options: petroleum-derived nylon and natural horsehair. What they're made of, how they perform, what they do inside your mouth, and what they leave behind when you're done with them.
Round 1: What They're Actually Made Of
Nylon bristles are synthetic polymers derived from petroleum. The most common variants used in toothbrushes are nylon-6,6 and polybutylene terephthalate (PBT). They are manufactured through an industrial chemical process, extruded into uniform filaments, and cut to the required length. Every bristle is identical — a feature of synthetic manufacturing, not of nature.
Horsehair bristles are exactly what they sound like: natural hair from horse mane and tail, collected as a byproduct of the equine industry. The hair is cleaned and sterilised using hot water only — no chemical processing. Natural colour variations in the bristles (typically dark brown) reflect their untreated, authentic origin. Each bristle is a natural keratin fibre — the same protein that makes up human hair and nails.
Winner: Horsehair — if your criterion is "no synthetic polymers in my mouth."
Round 2: Microplastic Shedding
This is the big one.
Nylon bristles shed microplastic particles during use. This has been confirmed by multiple peer-reviewed studies. A 2024 study in the Microchemical Journal found that all commercially tested toothbrushes released microplastics during simulated brushing — an average of 39 particles per day. These particles enter the mouth, mix with saliva, and are swallowed or absorbed through the mucous membranes.
Horsehair bristles, when they wear or shed, release keratin fibres — an organic protein material. Keratin is not a synthetic polymer. It does not classify as a microplastic. It is a naturally occurring biological material that the human body encounters in many forms.
This doesn't mean horsehair bristles are completely inert — any material introduced into the mouth warrants consideration. But organic protein fibres are categorically different from synthetic polymer fragments in terms of how the body processes them and what the long-term implications are.
Winner: Horsehair — by a significant margin on this criterion.
Round 3: Cleaning Performance
Here's where a lot of people expect nylon to win easily. It doesn't.
Nylon bristles are consistent and firm — they maintain their shape well, reach between teeth effectively, and deliver a reliably uniform clean. Dental associations have historically recommended them partly because they're standardised and predictable, not because they've been proven superior to natural alternatives in clinical settings.
Horsehair bristles are naturally soft and flexible — softer than even "soft" nylon bristles in most cases. They flex more readily, which some users find means they conform better to the curved surfaces of teeth and gums. The softness also means less enamel wear and less gum irritation, which is particularly relevant for the significant proportion of people who brush too hard.
Multiple user reviews of horsehair toothbrushes note that teeth feel genuinely clean after use — not just the surface sensation that some associate with nylon, but a thorough clean without the post-brush sensitivity that hard nylon bristles can cause.
The one area where nylon has a technical edge: because horsehair is a natural material, individual bristles can vary slightly in diameter and stiffness across a brush head. Some users notice this; most don't. It's a feature of natural materials, not a flaw.
Winner: Draw — nylon for uniformity, horsehair for gentleness and sensitivity.
Round 4: Hygiene and Care
Nylon bristles are hydrophobic — they repel water rather than absorbing it. This means they dry relatively quickly between uses and don't retain moisture in a way that encourages bacterial growth. This is the main hygiene argument for synthetic bristles.
Horsehair bristles are natural protein fibres and do absorb a small amount of moisture — similar to a natural hairbrush. This means they require slightly more attention to dry properly between uses. The care is simple: rinse thoroughly, shake out excess water, and allow to air dry upright. The KYND toothbrush is designed to stand on its own without a holder — place it bristle-side up on any flat surface and it dries completely between uses. The bamboo handle is also coated in 100% natural beeswax, which prevents moisture absorption into the bamboo itself, reducing any mold risk at the handle. These two features together make the natural bristle care routine as simple as possible.
The hygiene concern around natural bristles is largely theoretical in practice. People have been using natural bristle brushes and hairbrushes for centuries without this being a documented health problem. The key is simply to let it dry — which is good practice for any toothbrush regardless of bristle type.
Winner: Nylon — on paper, for ease of care. Horsehair requires slightly more attention but is manageable for anyone who knows what to expect.
Round 5: Environmental Impact
Nylon bristles are non-biodegradable. When your toothbrush reaches the end of its life, the nylon bristles will persist in the environment for hundreds of years. Even if the handle is bamboo, the bristles must be removed before composting — and in practice, most people don't do this, meaning the whole brush ends up in landfill or eventually in the ocean.
Horsehair bristles are fully biodegradable. When a horsehair bristle wears and falls out during normal use, it degrades into organic material — keratin returning to the environment. At end of life, the entire toothbrush (bamboo handle + horsehair bristles) can be composted whole. No separation required. No synthetic fragment left behind.
The environmental lifecycle of a horsehair toothbrush is as clean as a toothbrush can currently get. The handle is a renewable resource. The bristles are a natural byproduct. The packaging (if kraft cardboard) is compostable. From production to compost, every stage involves natural or sustainably harvested materials.
Winner: Horsehair — comprehensively.
Round 6: Cost
This one surprises people.
Nylon toothbrushes range from very cheap (supermarket multipack) to expensive (premium branded). Mid-range nylon toothbrushes — the kind most people buy — typically cost €2–4 per brush.
Horsehair toothbrushes have historically been more expensive, partly because of smaller production scale and a more involved supply chain. But as demand for natural alternatives has grown, the price gap has narrowed significantly.
KYND's 4-pack works out at roughly the same per-brush cost as a mid-range conventional toothbrush — without any compromise on quality and with a complete elimination of nylon from your oral care routine.
The premium natural option and the mainstream option are now at price parity. Which means cost is no longer a reason to stay with nylon. (See also: the problem with "good enough" oral care.)
Winner: Draw — at current pricing, the cost argument for nylon is largely gone.
The Scorecard: Horsehair vs Nylon
| Category | Nylon | Horsehair |
|---|---|---|
| Material origin | Petroleum-derived | Natural animal hair |
| Microplastic shedding | Yes (confirmed) | No (organic protein only) |
| Cleaning performance | Consistent, uniform | Gentle, effective, slightly variable |
| Hygiene / care | Easy, quick-drying | Simple with proper drying |
| Environmental impact | Non-biodegradable | Fully compostable |
| Cost | €2–4 per brush | Comparable at scale |
The scorecard isn't close on the criteria that matter most — what goes into your body and what gets left on the planet. Nylon wins on manufacturing consistency and ease of care. Horsehair wins on everything else.
The Bottom Line
The switch from nylon to horsehair is not a sacrifice. It's not a wellness compromise that requires you to accept a worse product in exchange for better values. It's a genuinely better bristle for most people — gentler, cleaner in terms of what it introduces into your body, and dramatically better for the planet at every stage of its life.
The reason most people are still using nylon is simply that nobody ever told them there was a choice. Now you know. The same logic applies across the bathroom — explored in small swaps, big impact and our bathroom chemical exposure breakdown.
Make the switch to horsehair. KYND's natural toothbrush 4-pack is available at trykynd.co — fully natural, fully compostable, same price as the toothbrush you're using now.
References
- Azoulay, D. et al. (2024). Preliminary results on microplastic release from commercial toothbrushes. Microchemical Journal.
- Gaia Guy (2024). The Return of the Horsehair Toothbrush. gaiaguy.com
- Aragaw, T.A. (2023). Microplastic release from bioplastic materials. Journal of Hazardous Materials.
- NBC News Select (2025). Are you brushing your teeth with microplastics? nbcnews.com