5 Reasons People Are Switching to PRIMALS Replacement Heads
Microplastics, glue, mold, and a "plant-based" fix that isn't one. Here's what a million people found out about the plastic head clicking onto their handle, and why they switched to the first natural bristle replacement head, in boar or horse, built for the PRIMALS Electric Toothbrush and most click-on handles.
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Every Nylon Bristle Sheds Microplastics Into Your Mouth, and a Sonic Motor Speeds It Up
A 2025 study measured nylon toothbrush bristles shedding 3,000+ particles per use, up to 2.3 million a year per person. On a sonic brush, tens of thousands of strokes a minute wear that nylon faster than any manual brush could.
- 🔬3,000+ particles per useMeasured on nylon toothbrushes. Twice a day, every day. (Ecotoxicology and Environmental Safety, 2025)
- 📅Up to 2.3 million a year, per personShedding rises fast with fresh bristles, then keeps going for the life of the head.
- ⚡Sonic motors wear nylon fasterFriction, flex, and recovery, 62,000 times a minute, on a plastic filament.
- 🩸Gum tissue absorbs, it doesn't rinseParts of the mouth are over 20 times more permeable than skin, so particles don't simply wash away.
Castor Oil Bristles Are Still Nylon. Just Partly Made From Beans.
If you bought a castor oil brush to go plastic-free, the bristle never actually changed. Castor beans are processed into nylon-11, a synthetic polymer in the same family as standard nylon. "Plant-based" describes the feedstock, not the material in your mouth.
- 🫘Castor oil is the feedstock, not the materialThe bean goes in. A plastic filament comes out. Nylon-11 is still nylon.
- 🔬Still a plastic polymer, still sheddingA nylon-11 bristle wears down under a sonic motor like any nylon bristle. Shedding from castor bristles hasn't been quantified, but it's plastic, and plastic bristles shed.
- 🪡Still stapled into glue wellsThe bristles are anchored with adhesive an inch from your gums, the same molded, glued construction as any plastic head.
- 💧Same hollow plastic head underneathSwap the bristle and the cavity that traps water is still there.
The Microplastics Don't Stay in Your Mouth. Researchers Keep Finding Them Inside the Body.
Once particles get past the gums, they travel. In the last few years researchers have found microplastics in blood, in artery plaque, in placentas, and in brain tissue, and they don't travel alone: nylon carries BPA and phthalates with it.
- 🧠In brain tissue, and climbingBrain samples from 2024 held about 50% more plastic than samples from 2016. (Nature Medicine, 2025)
- 🫀In artery plaque, with a risk signalPeople with plastic in their artery plaque had a 4.5x higher risk of heart attack, stroke, or death over three years. (NEJM, 2024)
- 🧬Linked to hormone markers in men and womenMicroplastics found in every human testis sample tested; phthalate exposure associated with lower testosterone in men and women. (Toxicological Sciences 2024; JCEM 2014)
- 🤰In placentas and bloodDetected in human placentas in 2021 and in the blood of most people tested in 2022. (Environment International)
These studies report where particles were found and statistical associations. They are not proof that a toothbrush causes any condition. They are a reason to stop adding to the load where you easily can.
Plastic Heads Are Molded Hollow. Water Sits Inside and Mold Grows Where You Can't Clean.
Every click-on plastic head has a cavity between head and shaft. It never fully dries, and the motor drives whatever grew overnight straight back into the mouth.
- 💧A cavity that holds water between brushesMolded hollow to save plastic. You can't rinse it, and you can't see it.
- 🌙Damp, dark, twelve hours at a timeSolid-head brushes carried significantly less microbial contamination than hollow heads in 8 of 10 comparisons. (J Dent Hyg 88(4):237)
- 🔁The motor sends it backOn the next brush, it's driven into the mouth, including toward the throat.
- 🎋PRIMALS heads are solid bambooHeat-carbonized, no hollow chamber, and boar and horse bristle are naturally antimicrobial, so the head dries instead of breeding.
The PRIMALS Replacement Head: Zero Microplastics, Solid Bamboo, Hand-Woven, No Glue
The first natural bristle replacement head. Real boar or horse bristle hand-woven into a solid bamboo head that clicks onto the PRIMALS Electric Toothbrush, the first natural bristle electric toothbrush, and most click-on handles. Zero nylon, zero microplastics to shed, and no hollow chamber for mold.
- 🐗Boar head for a firmer, deeper cleanThe sturdier natural bristle, for healthy gums that want a thorough scrub. Zero nylon.
- 🐴Horse head for sensitive gums and dental workThe softest natural bristle, for receding gums, crowns, implants, or aligners. Zero nylon.
- 🎋Solid bamboo head, nothing hollow to trap waterHeat-carbonized bamboo with no sealed cavity, so the head dries instead of breeding. Boar and horse bristle are naturally antimicrobial.
- 🧵Hand-woven into bamboo, no glue, no staplesPlastic heads staple nylon into glue wells an inch from your gums. Ours are set by hand.
- 🔁Fits most click-on handlesBuilt for the PRIMALS Electric Toothbrush and compatible with most click-on electric handles.
- 🎁4-pack value, free gifts with every bundleA 4-pack covers most of a year. Ships next day from California.
PRIMALS vs the Leading Plastic Head vs the Castor Oil Head
| What you're brushing with | PRIMALS Head | Leading plastic head | Castor oil head |
|---|---|---|---|
| Bristle material | Real boar or horse | Nylon | Nylon-11 (castor-derived) |
| Sheds microplastics | No | Yes, up to 2.3M a year | Yes, still plastic |
| Head construction | Solid bamboo | Hollow plastic | Hollow plastic |
| How bristles are set | Hand-woven, no glue | Stapled in glue wells | Stapled in glue wells |
| Naturally antimicrobial | Yes, boar and horse | No | No |
| Fits most click-on handles | Yes, incl. PRIMALS | Handle-specific | Handle-specific |
"Leading plastic head" refers to a nylon-bristle replacement head as a category; "castor oil head" to a castor-oil-bristle replacement head. Microplastic figures are published research on nylon-bristle brushes as a category; castor bristle shedding has not been quantified. Heads are built for the PRIMALS Electric Toothbrush and fit most click-on handles.
Over a Million People Have Switched to PRIMALS
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One Natural Bristle Head, Two Firmness Options
Same solid bamboo head, same zero-nylon promise, built for the PRIMALS Electric Toothbrush and most click-on handles. Choose how it feels on your gums.
🐗 Boar Bristle Heads
The firmer natural bristle, for a deeper, thorough clean on healthy gums.
- ✅ Real boar bristle, zero nylon, zero microplastics
- ✅ Solid bamboo head, no hollow chamber for mold
- ✅ Hand-woven, no glue, no staples
- ✅ 4-pack, fits most click-on handles
🐴 Horse Bristle Heads
The softest natural bristle, for sensitive or receding gums, crowns, implants, and aligners.
- ✅ Real horse bristle, zero nylon, zero microplastics
- ✅ Solid bamboo head, no hollow chamber for mold
- ✅ Hand-woven, no glue, no staples
- ✅ 4-pack, fits most click-on handles
Founded in Hawaii by a Woman Who Was Done Reading Labels
Lauryn started PRIMALS because every product she picked up turned out to be plastic, synthetic, or both, and the clean version didn't exist. It began with one boar bristle toothbrush. Now it's more than 20 products, and over a million people. The electric was built to the same standard: remove a toxin, don't add a feature.
Everything You Might Be Wondering
Will these fit my toothbrush?
How often should I replace the head?
Does a natural bristle clean as well as nylon?
Boar or horse, which should I get?
Are castor oil bristles really plastic?
How is the head different from a plastic one?
What's in the box?
Zero microplastics. No glue. No hollow head. Solid bamboo. Boar or horse.
The first natural bristle replacement head, built for the PRIMALS Electric Toothbrush and most click-on handles. Every restock has sold out.