Is Micro or Nano Hydroxyapatite Safer? A Complete Guide to Remineralizing Toothpaste
If you're looking for a fluoride-free, enamel-safe toothpaste, you've likely come across hydroxyapatite — but not all hydroxyapatite is created equal. So, what's the difference between nano-hydroxyapatite and micro-hydroxyapatite, and which one is safer?
At Terra & Co., we receive this question often, especially from customers who care deeply about ingredient safety, holistic oral health, and choosing clean alternatives to fluoride.
In this guide, we’ll break down:
- What hydroxyapatite is and how it works
- The difference between nano and micro hydroxyapatite
- The potential risks of nano-sized particles
- Why Terra & Co. uses micro-cluster hydroxyapatite
- FAQs optimized for SEO and voice search
What Is Hydroxyapatite?
Hydroxyapatite (Ca₅(PO₄)₃(OH)) is a naturally occurring mineral form of calcium apatite and the main mineral component of human enamel and dentin. It's also found in bones. In oral care, it’s used as a biocompatible fluoride alternative that helps remineralize teeth, reduce sensitivity, and protect enamel from daily wear.
Fun fact: The hydroxyapatite in Terra & Co. toothpaste is vegan, sustainably derived from organic mineral sources in France—not animal bone or synthetic labs.
What Is the Difference Between Micro and Nano Hydroxyapatite?
The key difference lies in particle size:
| Feature | Nano Hydroxyapatite (nHA) |
Micro Hydroxyapatite (μHA)
|
|---|---|---|
| Particle size | ~20–100 nanometers (nm) | ~5–10 microns (μm) |
| Origin | Often synthetic | Naturally sourced from rock minerals |
| Absorption | Can penetrate deeply into enamel, soft tissue, or possibly the bloodstream | Remains on the tooth surface or saliva; too large to penetrate cells |
| Safety concerns | May cross gum tissue, enter bloodstream, or affect the blood-brain barrier | No known health risks; too large to be absorbed |
| Regulatory status | Approved in the EU at ≤10% in toothpaste only | GRAS (Generally Recognized As Safe) status; no EU restrictions |
| Ideal use | Deep remineralization, hypersensitivity | Daily remineralization, holistic oral care |
Why Is Nano Hydroxyapatite Controversial?
While nano-hydroxyapatite (nHA) is effective for desensitizing teeth and sealing dentin tubules, its nano-scale size raises safety concerns. According to a 2023 review by Today’s RDH:
“Due to their small size, nano-HA particles can potentially migrate into tissues, including gum tissue and blood vessels, and possibly pass the blood-brain barrier.”
Because nano-particles are small enough to enter cells, there is growing concern in the wellness and holistic health communities over long-term exposure, especially in children.
Some scientists also warn that the needle-like shape of certain nHA formulations could pose health risks when used in spray or inhalable products.
Why Terra & Co. Uses Micro Hydroxyapatite
At Terra & Co., safety is our priority. That's why we use micro-cluster hydroxyapatite (μHA) in all our toothpaste formulas, including:
Key Benefits of Micro-Hydroxyapatite:
- Naturally remineralizes enamel without synthetic additives
- Vegan and fluoride-free — derived from mineral deposits, not animal bones
- Safe to swallow — ideal for kids, pregnancy, or anyone avoiding fluoride
- Too large to penetrate the gum tissue or organs
- Backed by dentists and functional medicine practitioners
Our formulas contain 8–10% micro-HA, which aligns with clinical studies suggesting this concentration is ideal for surface remineralization and enamel integrity.
Is Micro Hydroxyapatite as Effective?
Yes! While nano-HAp may penetrate deeper into enamel, micro-HA is still effective at:
- Repairing microscopic enamel damage
- Reducing tooth sensitivity
- Supporting a healthy oral microbiome
- Offering a safe, non-toxic fluoride alternative
In fact, micro-HA may be better for long-term daily use due to its excellent safety profile and biocompatibility.
Frequently Asked Questions (FAQs)
Q1: What type of hydroxyapatite does Terra & Co. use?
We use micro-cluster hydroxyapatite, derived from organic mineral sources in France. It is not synthetic and not nano-sized.
Q2: How much hydroxyapatite is in Terra & Co. toothpaste?
Both our Gentle Green and Brilliant Black® Toothpaste formulas contain 8–10% micro-hydroxyapatite, an ideal concentration for enamel repair and daily use.
Q3: Is micro-hydroxyapatite safe to swallow?
Yes. Micro-HA is non-toxic, fluoride-free, and too large to pass through gum tissue or into the bloodstream, making it safe for children and adults alike.
Q4: Is nano-hydroxyapatite dangerous?
While approved in some regions at controlled concentrations, nano-HA’s small size raises questions about tissue absorption, neurotoxicity, and long-term exposure. Micro-HA is a safer alternative with no such risks.
Q5: Does Terra & Co. use fluoride?
No. All Terra & Co. products are 100% fluoride-free and formulated with non-toxic, holistic alternatives like hydroxyapatite, activated charcoal, and coconut oil.
Final Thoughts
Micro-hydroxyapatite is a powerful, science-backed alternative to fluoride that supports strong enamel, reduces sensitivity, and promotes a healthy mouth, all without the potential risks of nanoparticles
