Today’s newsletter is more technical than usual. If you love data, you’ll enjoy this deep dive—it exposes one of the biggest myths in oral health right now.
For those who prefer the plain-English version, here’s a simple breakdown of what you’ll learn:
- The “10% nano-hydroxyapatite” claim is a myth.
- A new peer-reviewed study compared Fygg’s 3.1% nano-Hydroxyapatite formula against Boka, Risewell, Just Ingredients, Dr. Jen, Crest Cavity Protection, and ClinPro 5000 (a prescription-strength 5000 ppm fluoride toothpaste).
- Quality of particles—not quantity—makes the difference.
- Too much nHA clumps, reduces enamel binding, and works less effectively.
There’s a funny thing that happens in the world of health…
Someone misreads the science, then turns that misinterpretation into a marketing slogan, and before you know it, everyone’s treating it like gospel.
We’ve seen this movie before. Nina Teicholz’s The Big Fat Surprise is a case in point: early misinterpretations of nutrition research—like blaming dietary fat for heart disease—were enshrined in official guidelines and amplified by marketing.
That decades‑long detour into low‑fat advice fueled obesity, diabetes, and heart disease. A perfect example of how bad science interpretation killed a lot of people.
In the world of hydroxyapatite toothpastes, that slogan has become: “It has to be 10% nano-hydroxyapatite—or it doesn’t work.” And it’s flat out wrong.
Instagram influencers parroted the 10% thing like gospel. One brand built its whole identity around that number. Some even implied that if your toothpaste didn’t hit that number, it wasn’t doing anything at all.
For a split second, I second‑guessed our formula at Fygg. I asked colleagues and critics to show me the studies that supposedly proved the 10% claim. Over and over, the evidence didn’t hold up.
The deeper I looked, and the more I spoke to the biochemists and oral microbiome scientists, the more insane the 10% claim appeared to be. Because if you’ve spent enough time in the science—really looked at how the oral microbiome works, how mineral particles behave in the mouth—you know: more isn’t always better.
In fact, too much nano-hydroxyapatite (nHA) can actually work against you.
Here’s why I’m writing about this today—thanks to a brand-new, peer-reviewed, Fygg-funded study, we finally have the data to show exactly why that decision was the right one.
Just published in the Journal of Dentistry (2025), this in vitro study tested eight major remineralizing toothpastes—including fluoride, nano-HAP, micro-HAP, and yes, a well-known “10% nano-HAP” brand.
Direct from the study: “The superior efficacy of Fygg over Dr. Jen and Risewell is likely attributable to its enhanced physicochemical properties, rather than simply the concentration of active ingredients. In contrast, regarding Boka, Fygg’s superior performance may primarily result from the higher concentration of nanoXIM in its formulation.”
And it did that using just 3.1% nano-hydroxyapatite.
Even more striking: Fygg toothpaste performed on par with prescription‑strength fluoride toothpaste—the gold standard for remineralization, often $20-27 and only available with a doctor’s prescription.
How can that be?
Why More Isn’t Better
You can’t just keep adding more and expect better results. In fact, too much nHA can lead to aggregation (it won’t dissolve so it starts clumping into big chunks)—which decreases how well it disperses across the enamel surface, reduces bioavailability, and as proved by the study, reduces ability to reverse cavities.
“Particle size and formulation design appear to play a pivotal role in the therapeutic outcome… The superior efficacy of Fygg was likely due to its optimized particle morphology and lower concentration of nanoXIM.” (Journal of Dentistry, 2025)
I appreciate that quote and this is part of our secret sauce, but there’s more to the formula than that—I can go into this in more detail in a future newsletter, if folks are interested. We were looking for the right concentration of nano-Hydroxyapatite in saliva, for it to be stored in saliva before it’s taken up by the tooth. Clumping or “clogging” the saliva doesn’t work well—it’s like adding too much salt to water and some of it doesn’t dissolve.
NanoXIM is a proprietary blend of nHA engineered at just the right size—smaller than 50nm, with a precise rod-shaped morphology—designed to mimic natural enamel.
Why the 10% Claim Is Wrong
The 10% number is based on a 2009 and 2011 study from China when, back then, the scientific community had not yet defined the size of “nano” and the uniformity and purity.
10% was the lowest threshold at which crude samples of nano-hydroxyapatite started to show a measurable effect. But technology has moved on. Particle morphology, surface charge, delivery medium—all of that matters more than brute concentration. Lots of brands out there are using micro-sized particles, and the uptake of micro is simply not as good as nano.
Unfortunately in that crude sample were pieces of nano hydroxyapatite that do not fit the current SCCS guidelines for safety. (that’s a different argument but what they’re doing is doping the formula, making it less safe, when 2 and 3% works just fine IF it is pure and high quality).
Fygg uses 20% NanoXIM paste, which contains 15.5% nHA, resulting in a 3.1% total active nHA—and that was proven to be more effective than the full 10% in other pastes.
“HAP particles larger than 1.3 μm have limited adhesion to enamel, while those below this threshold exhibit strong surface binding… Conventional micro-HAPs frequently contain particles exceeding 5 µm, which show little to no effective enamel adhesion.” (Journal of Dentistry, 2025)
When I decided I wanted to make a toothpaste, it was of utmost importance to me that if I was convincing parents to go fluoride-free, the alternative worked as well—if not better. That meant working with chemists, researchers, and oral microbiome experts to find the exact ratio that would…
- Penetrate subsurface lesions for increased depth of remineralization
- Avoid aggregation (clumping of nHAp particles making them less effective and available for remineralization)
- Respect the oral microbiome (the engine for remineralization)
And now, we finally have a peer-reviewed study to confirm what chemists and scientists have known all along!
It’s easy to believe that if something is good, more must be better. But there is always a sweet spot when it comes to metabolism and biological processes and systems—things like pH balance, oxygen saturation in the blood, and countless other finely tuned functions. Too much and too little can be deadly in those two systems.
So, it’s not “what’s the right amount for teeth” it’s “what’s the right amount for saliva” so that teeth can actually grab it when needed!
I’m proud Fygg led with science. And I’m grateful to the researchers who proved what we knew all along.
Here’s to science, healthier mouths, and fewer clumps in your toothpaste.
Dr. B
P.S. Know someone who is parroting the 10% myth? Forward this to them — they never have to miss another newsletter if they sign up for future emails here.