A migratory robin can find its way across a continent in the dark using nothing but the Earth's magnetic field. That sense is so fine that a faint hum of everyday electromagnetic noise can switch it off completely. It is a strange thing to hold in your head while you brush your teeth, because electric toothbrush EMF is one more source of that same everyday noise, sitting inches from your skull twice a day.
What EMF does to a bird's compass
Migratory birds like the European robin carry an internal magnetic compass. The sense is thought to rely on light-sensitive cryptochrome proteins in the eye, and the signal is handled by a region of the bird's forebrain that researchers named cluster N. It is, in a real sense, navigation run through the brain.
In a 2014 study published in Nature, researchers at the University of Oldenburg found that robins kept in ordinary wooden huts on campus could not orient at all. When they electrically grounded and shielded the huts, cutting the background electromagnetic noise by about a hundredfold, the birds' compass came back. The result held up double-blind and reproducible. The mechanism behind that compass, down to the magnetically sensitive cryptochrome protein, is still being mapped today.
Everyday electromagnetic noise, at strengths below WHO exposure guidelines, switched off migratory robins' magnetic compass. Shielding it out switched the compass back on. (Nature, 2014)
Why birds are not the same as you
Here is where honesty matters more than a good headline. That magnetic compass is a specialized sense. The scientists who ran the study have been clear that it may be unique to migratory birds and may not exist in mammals or people at all. So the robin result does not prove that EMF harms the human brain, and this post will not pretend otherwise.
That is still worth sitting with. For decades the debate over whether everyday human-made fields affect biology stayed unsettled because nothing survived a properly blinded test. The bird compass was the first effect that did. It is a reminder to be thoughtful about exposure you can easily control, and to lean on the World Health Organization's guidance rather than hype in either direction.
What electric toothbrush EMF reads on the meter
Exposure is cumulative. It adds up across your phone, your laptop, your home wiring, and everything else, all day. Most of that is hard to change. A toothbrush is one of the easy ones, and it happens to sit against your head while its motor runs. So we measured the PRIMALS Electric Toothbrush, which comes in boar and horse bristle versions on the same low-EMF handle, against a leading plastic electric toothbrush on the same meter, held the same distance away.
| Measurement | Leading plastic electric toothbrush | PRIMALS Electric Toothbrush | Difference |
|---|---|---|---|
| Electric field (V/m) | 265 | 14 | 19x less electric field |
| Magnetic field (µT) | 88.29 | 17.62 | 5x less magnetic field |
| Bristle | Plastic nylon | Natural bristle (boar or horse) | First natural bristle electric toothbrush |
The leading plastic electric toothbrush read 265 V/m on the electric field. The PRIMALS Electric Toothbrush read 14, which is 19x less electric field. On the magnetic field it was 88.29 microtesla against 17.62, which is 5x less magnetic field. These numbers are not zero, because any running motor gives off a field you can measure. It is way less radiation reaching you while you brush, not none.
I came across the robin study long after we had started building the brush, and it stopped me cold. Not because it says anything about people, it does not, but because it showed how fine the line is between a living thing and the noise we surround it with.
It made me glad we had already decided to measure our own brush instead of guessing. If a bird can feel a field that faint, the least we can do is know exactly what ours puts out, and bring it as low as we can.
Lauryn, founder of PRIMALS
Meet the PRIMALS Electric Toothbrush
One low-EMF handle, two natural bristle options. Boar for a firmer, deeper clean. Horse for the softest touch on sensitive gums.
The electric toothbrush EMF you can actually lower
You cannot shield your whole life the way those researchers shielded a hut for their robins. But you can pick the version of a daily device that reads lower. The PRIMALS Electric Toothbrush is the first natural bristle electric toothbrush, low-EMF engineered from the start, and it still runs the full powered clean at 62,000 movements a minute. You keep the deep clean and drop the reading.
It comes in two natural bristle options on that same low-EMF handle. The boar bristle version gives a firmer, deeper clean, while the horse bristle version is the softest natural bristle available, made for sensitive gums, receding gumlines, and kids aged 6 and up. Both read the same low fields, because they share the same handle and motor, so the choice is only about how firm you like the clean.
It also takes natural bristle heads, so the whole routine stays plastic-free. If you are keeping a handle you already own, our guides on natural bristle replacement heads that fit standard handles and horse bristle heads for sensitive gums cover the options either way.
Frequently asked questions
Does EMF really affect birds?
Yes. A double-blind study in Nature (2014) found that migratory robins lost the use of their magnetic compass when exposed to everyday human-made electromagnetic noise, at levels below WHO limits, and regained it once that noise was shielded out.
Does that mean my electric toothbrush is damaging my brain?
No. The bird finding is about a magnetic navigation sense that humans are not known to have. It does not show harm to the human brain. It is a reason to be thoughtful about cumulative exposure you can easily lower, not a reason to panic.
How much lower is the PRIMALS Electric Toothbrush?
On the same meter, 19x less electric field (14 versus 265 V/m) and 5x less magnetic field (17.62 versus 88.29 microtesla) than a leading plastic electric toothbrush.
Is it zero EMF?
No, and no powered brush is. Any running motor produces a field. The PRIMALS Electric Toothbrush simply reads far lower than a leading plastic electric toothbrush on both fields at once.
Should I choose boar or horse bristle?
Both share the same low-EMF handle, so the readings are the same. Choose boar bristle for a firmer, deeper clean, or horse bristle for the softest touch on sensitive gums, receding gumlines, and kids aged 6 and up.
Keep the clean. Drop the reading.
Pick your bristle. Both are low-EMF engineered and both are the first natural bristle electric toothbrush.
