What Is Hydroxyapatite Toothpaste?

Written by Ana Gascon Ivey
Medically Reviewed by Robert Brennan, DDS on July 30, 2025
7 min read

Hydroxyapatite (HAP) toothpaste is a dental product that contains manufactured calcium phosphate. Calcium and phosphate are minerals that form 95% of tooth enamel and 70% of bones. 

NASA developed HAP toothpaste in the 1970s. In gravity-free conditions, astronauts were losing mineral content from their teeth. HAP toothpaste "remineralized" their teeth, depositing calcium phosphate back onto them.

A Japanese company bought the rights to synthetic HAP from NASA in 1970 and made the first commercially available hydroxyapatite toothpaste. In 1993, the Japanese government approved hydroxyapatite toothpaste as an anti-cavity product. Since then, it has become available around the world 

In the U.S., the FDA has not approved any hydroxyapatite toothpaste. It also does not carry the Seal of Acceptance from the American Dental Association (ADA). You can still buy it online. 

Hydroxyapatite toothpaste vs. nano-hydroxyapatite toothpaste

The difference between hydroxyapatite toothpaste and nano-hydroxyapatite toothpaste is the particle size. Nano-hydroxyapatite toothpaste contains particles that are one nano or smaller in size. There are 25,400,000 nanos in one inch. This may make it better at filling smaller cracks in tooth enamel. 

Dentists and oral surgeons use nano-hydroxyapatite to:

  • Prevent and treat periodontal disease.
  • Re-create bone after oral surgery.
  • Coat the surface of dental implants and improve how they bind to bone.

Nano-hydroxyapatite toothpaste, like HAP, is not approved by the FDA. It also does not have the ADA’s Seal of Acceptance.

Hydroxyapatite toothpaste works by filling in tiny cracks and weak spots on teeth caused by acids in foods. HAP sticks to teeth and puts calcium and phosphate back into the enamel. This process is called remineralization. 

"Hydroxyapatite adds a protective layer on the surface of the tooth, particularly in areas of dental erosion," explains Bennett Amaechi, PhD, a dentistry professor at the University of Texas, San Antonio, and a leading U.S. researcher on hydroxyapatite toothpaste. "When acid from food attacks a tooth, it attacks the layer of hydroxyapatite before it can attack the natural tooth."

 This added layer protects teeth from erosion, decay, and cavity formation. 

Studies show that hydroxyapatite toothpaste and fluoride toothpaste help remineralize teeth and fight cavities. But they do so in different ways. To compare the two, it’s important to understand how fluoride works.

What is fluoride?

Fluoride is a mineral found in soil, rocks, and water. Research on fluoride began in Colorado in the early 1900s. In the 1940s, researchers found that adding low levels of fluoride to public drinking water greatly reduced cavity rates in children. Since then, municipalities across the U.S. have added fluoride to public drinking water.

In 1956, the first fluoridated toothpaste became commercially available. Fluoride became the primary weapon for battling tooth decay. Today, the American Dental Association gives its Seal of Acceptance only to fluoride toothpaste.

How does fluoride work? 

Food acids and bacteria can harm your teeth. They break down the minerals on tooth enamel. This process is called demineralization. As tooth enamel weakens, it becomes vulnerable to erosion and decay.

"Fluoride interacts with tooth enamel and facilitates the formation of fluorapatite [calcium phosphate]," explains Domenick Zero, DDS, a professor at Indiana University School of Dentistry and an ADA spokesperson. "Fluoride not only slows down or inhibits the demineralization of the tooth, but it also enhances and accelerates the remineralization of the tooth."

What about claims against fluoride?

You may have seen news reports linking fluoride to cancer, thyroid disease, neurodevelopmental disorders, and other health risks.

Most of the evidence around these claims focuses on fluoridated water, not fluoride toothpaste. One study linked drinking water containing more than 1.5 milligrams of fluoride per liter to lower IQs in children. Most U.S. community drinking water has .07 milligrams of fluoride per liter. Other studies have found no connection between early exposure to fluoridated water and IQ. 

"It’s clear in my mind, based on the totality of evidence, that the risk of any potential negative health effects from fluoride is very, very low. It has a long history of being effective and safe," says Zero. 

The science behind HAP, while optimistic, is still relatively new.

Early research shows promise for hydroxyapatite toothpaste. Scientists have discovered several benefits, from stronger tooth enamel to whiter teeth. Most of these have been small studies. We need more large randomized controlled trials to know for sure if these benefits are accurate. 

Remineralization

The main benefit of hydroxyapatite toothpaste seems to be its mineral content. HAP toothpaste contains calcium and phosphate, the building blocks of tooth enamel. Hydroxyapatite sticks to tooth enamel, replacing minerals lost to erosion and decay, and adding a layer of protection against food acids. 

Sensitivity 

Several small studies suggest that HAP toothpaste makes teeth less sensitive. In one study, scientists tested cold air sensitivity and tactile (touch) sensitivity. After two weeks and four weeks, people who used nano-HAP toothpaste were less sensitive in both categories. 

Whitening

Early studies, mostly done in laboratories, suggest that HAP toothpaste whitens teeth. The protective layer that HAP toothpaste adds to teeth is made of white opaque particles. As these particles stick to tooth enamel, they mask yellow coloring on teeth and remove stains and plaque.

So far, scientists believe hydroxyapatite toothpaste is safe. It doesn’t seem to penetrate or damage cells in the mouth or elsewhere in the body if ingested. 

In Europe, the Scientific Committee on Consumer Safety (SCCS) questioned the safety of nanoparticles in nano-HAP cosmetic products. The committee found that nano-hydroxyapatite is safe in concentrations up to 29.5% in toothpaste after reviewing existing research. Most commercially available nano-hydroxyapatite toothpaste contains HAP concentrations of 10% or less.

In laboratory studies, ingestion of HAP raised calcium levels in cells. Too much calcium (hypercalcemia) can weaken bones and cause kidney stones. But scientists found that affected cells were able to manage high calcium levels and return to normal. Amaechi says there’s a lack of evidence that shows hydroxyapatite toothpaste causes kidney stones. 

What are the downsides of hydroxyapatite toothpaste?

Zero calls hydroxyapatite toothpaste the "new kid on the block." He says he believes more research needs to be done before dentists widely accept it.

If you want to try it, consider adding it to your routine rather than replacing fluoride toothpaste completely. Bear in mind that: 

  • The FDA has not approved hydroxyapatite toothpaste as an anti-cavity product.
  • No hydroxyapatite toothpaste has the ADA's Seal of Acceptance. 
  • A tube of HAP toothpaste runs between $5 and $25, with an average price of $15. Fluoridated toothpaste costs from $1 to $6 a tube.
  • HAP toothpaste is not widely available in the U.S. You can order it online.

Hydroxyapatite toothpaste seems safe and suitable for use in children. Many younger children accidentally swallow toothpaste. Evidence suggests that swallowing HAP does not harm children.

In small studies, children who used HAP toothpaste had less decay than children who used regular toothpaste. Some studies show that HAP toothpaste works as well as fluoride toothpaste for treating cavities and remineralizing teeth. 

Most hydroxyapatite toothpastes don’t have fluoride. For parents and caregivers worried about fluorosis – which happens when you take in too much fluoride, changing the color of your teeth – HAP may be a good alternative. Talk to your child’s dentist first before switching to HAP toothpaste.

  • Hydroxyapatite toothpaste is a newer type of dental product that is made mostly with synthetic calcium phosphate. 
  • Calcium and phosphate are minerals found in tooth enamel and bones. 
  • When food acids contact teeth, they weaken teeth by breaking down minerals in tooth enamel. Early research shows that hydroxyapatite toothpaste deposits minerals back into the teeth, making them stronger and more resistant to bacteria. 
  • Before you trade your fluoride toothpaste for HAP, talk to your dentist. Fluoride toothpaste is still considered the best anti-cavity weapon on the market. 

Why did Europe ban hydroxyapatite?

Europe has not banned hydroxyapatite. Some European scientists raised safety concerns about the nanoparticles in nano-hydroxyapatite. The European Commission’s Scientific Committee on Consumer Safety (SCCS) looked at the data and found that nano-HAP toothpaste is safe.

Can you reverse cavities with hydroxyapatite?

Hydroxyapatite can help fix early cavities. It fills cracks and crevices on the tooth’s surface with calcium and phosphate. These minerals make teeth resistant to decay. 

Why isn’t hydroxyapatite FDA-approved?

 The FDA has approved hydroxyapatite for use in medical applications, such as:

  • Bone grafting to reconstruct defects in the mouth, face, or jaw
  • Coating for orthopedic implants that promotes bone growth into implants (knee replacement, hip replacement)
  • Dermal fillers for wrinkles on the face and hands

The FDA has not approved hydroxyapatite toothpaste for cavity prevention. Currently, the FDA only approves toothpastes with fluoride. 

Does hydroxyapatite regrow enamel?

Hydroxyapatite regrows enamel by binding to microscopic gaps in the teeth. This process rebuilds and strengthens enamel.

Which is better: hydroxyapatite or fluoride?

Both hydroxyapatite and fluoride toothpastes have advantages and disadvantages. Research suggests HAP toothpaste is safe to use and can strengthen tooth enamel. It’s more expensive and not currently approved by the FDA or ADA. Research is still relatively new on hydroxyapatite toothpaste. 

Fluoride toothpaste has been the gold standard of oral health in the U.S. for more than 70 years. Studies consistently show that fluoride toothpaste is a safe and effective cavity fighter.

Does hydroxyapatite cause kidney stones? 

Hydroxyapatite (calcium phosphate) is found in urine and kidney stones. Small HAP crystals can damage the kidneys and contribute to kidney stone formation. 

Does hydroxyapatite make your teeth yellow?

No, hydroxyapatite does not make your teeth yellow. Studies show that HAP gives teeth a whiter, glossier appearance. 

Does hydroxyapatite damage DNA?

Most studies on the effects of hydroxyapatite on DNA have been done in laboratories. Many of these studies show that hydroxyapatite does not damage DNA. In some cases, it might protect DNA. Scientists need to do more research before they can guarantee no harm to human DNA.