What Is n-HA? How Nano-hydroxyapatite Superpowers Your Smile

Have you heard of hydroxyapatite? It’s a mouthful to say (pronounced “hahy-drok-see-ap-uh-tahyt”). It’s also a leading ingredient in top-shelf toothpastes around the world. In fact, Cocofloss co-founder Dr. Chrystle Cu chose it to star in our smile-strengthening Cocoshine Whitening Toothpaste. 

But what is hydroxyapatite and why is it good for our teeth?

Space Paste: How NASA Rocket-boosted the Hydroxyapatite Trend

We know, hydroxyapatite (abbreviated as “HA”) sounds like a precious metal from another planet. That’s fitting because it was first added to toothpaste by NASA in 1970 to help astronauts cope with bone and enamel loss caused by floating around in zero-gravity space.

But despite the galactic-sounding name, HA is actually a mineral that occurs naturally in our bodies. Composed mostly of calcium and phosphate, HA makes up 50 to 60% of our bones and 97% of our tooth enamel. This high concentration of hydroxyapatite is why our enamel is the hardest substance in the human body and our first defense against tooth decay. 

While we usually can’t repair parts of our bodies by directly applying the elements that compose them (wouldn’t that be a nice easy fix for kiddos’ skinned knees!), we can remineralize our teeth with hydroxyapatite — if it’s in the right form. 

Brush Booster: Hydroxyapatite Strengthens Enamel From the Inside Out 

After NASA experimented with rocket-boosting toothpaste with HA, a Japanese company bought the rights to create their own HA toothpaste with synthetic nano-hydroxyapatite (n-HA). The nanoparticles are so small, they are invisible to the human eye — but our bodies know what to do with them. The smaller the HA particles are in size, the more bioavailable (easily absorbed and used by the body) they become.

The n-HA in toothpaste fills in small fissures and depressions on the enamel and penetrate below to rebuild and fortify your teeth, or deeply remineralize them. As explained in the New York Times, “Your teeth have pores, and micro-hydroxyapatite can get in those pores and strengthen them from the inside out.” 

By remineralizing your enamel, n-HA can actually reverse the smallest cavities before they cause serious damage. “Remineralization is reversal of the smallest cavities,” clarifies Dr. Chrys. “Though if someone has a big active carious lesion [cavity], it's not likely to reverse it.” (So don’t wait to take extra good care of your smile.)

It’s no surprise that n-HA toothpaste became the A+ standard for oral care in Japan, raising the eyebrows of dental pros around the world and leading to robust research. A 2014 study summarizing the research stated, “Nano-hydroxyapatite is a revolutionary material with a wide use in dentistry.” 

So why is it just becoming more popular in the U.S.?

Nontoxic Fluoride Alternative: Hydroxyapatite Is Safe to Swallow

For most of modern oral-care history, fluoride has been the go-to ingredient for enamel repair and remineralization. It’s a proven cavity-fighter. But it’s also controversial.

While fluoride has been deemed safe to use at the levels found in most oral-care products and fluoridated drinking water, it’s toxic at high doses. It also has side effects (like fluorosis) when consumed in moderate doses over long periods of time, especially while teeth are developing. 

A growing awareness about clean ingredients points the way to n-HA: hydroxyapatite is completely nontoxic and safe to swallow, according to multiple studies. Ongoing research has also shown that n-HA is as effective as fluoride in preventing cavities and remineralizing enamel. 

“Hydroxyapatite can be safely used to remineralize teeth without the worry of reaching toxic exposure,” says Dr. Chrys. In fact, she suggests leaving HA on your teeth overnight to boost its remineralizing powers.

(Read more in our blog post about how fluoride and hydroxyapatite compare and contrast in our blog post about these two smile-strengthening ingredients.)

Smile Superpowers: Other Big Benefits of Nano-Hydroxyapatite 

Besides deeply remineralizing your teeth, n-HA boasts some other impressive benefits:

✨ Reduced teeth sensitivity and pain. By strengthening enamel, n-HA makes your smile less sensitive to heat, cold, and textures.

✨ Smoother, whiter, shinier teeth. Tiny crystals of white n-HA fill in the micro-crevices in your enamel, including little spots that accumulate stains, helping your teeth to regain their brightness and luster. Hello, whiter smiles!

✨ Protection against bacteria sticking to your teeth. Early research shows that n-HA creates a shield-like layer that makes your enamel more resistant to the bacteria that cause plaque, a sticky, acidic biofilm that can harden into stinky, yellow tartar and lead to gum disease and cavities.

✨ Maintains a healthy oral microbiome. Many oral products, such as common mouthwashes, effectively “carpet bomb” all the bacteria in your mouth, both good and bad. N-HA does not kill bacteria, but helps prevent it from creating plaque (see above). In the long run, maintaining the balance of bacteria in your mouth is essential to the health of your smile.

✨ May improve gum health and help fight gum disease, according to preliminary research.

Hydroxyapatite: Top Shelf in the Toothpaste Aisle

With all of these benefits, you’d think n-HA might have taken over the toothpaste aisle. But its relatively slow rise in U.S. popularity is also due to its price.

While it’s possible to extract hydroxyapatite from fish or animal bones, shells, or other natural sources (often called “microcrystalline-hydroxyapatite” or “micro-hydroxyapatite”), HA must be synthesized in a lab to maintain a consistent high quality. Plus, since HA becomes more readily absorbed by enamel when it’s in nano form rather than in the larger micro form, the lab must be able to create these very small particles — currently a more expensive process than producing fluoride for toothpaste.

Toothy tip: Different n-HA toothpastes contain varied quantities and qualities of hydroxyapatite. For the best results, look for a paste with a high concentration of top-quality n-HA, like Cocoshine.

Despite the cost, hydroxyapatite has become a new star ingredient in toothpastes as people seek effective, nontoxic alternatives to fluoride with added benefits. Some pros believe n-HA may even be better than fluoride. The technology for creating it is also becoming more advanced. So it may not be long before top-shelf n-HA toothpaste is found on most everyone’s bathroom shelf — including yours.