Hydroxyapatite is a calcium-phosphate mineral complex that provides bone and teeth with their structural hardness and integrity. Medically, it has been used as an implant for bone and dental surgeries, in toothpaste, and as a supplement for dental health. Hydroxyapatite can be made synthetically from chemical salts, which may have some salt impurities and can have lower calcium levels, or it can be extracted from natural sources like fishbone, coral, bovine bone, eggshell, and seashells.[3]
What is hydroxyapatite?
Hydroxyapatite is a calcium-phosphate mineral complex that provides bone and teeth with their structural hardness and integrity. Medically, it has been used as an implant for bone and dental surgeries, in toothpaste, and as a supplement for dental health. Hydroxyapatite can be made synthetically from chemical salts, which may have some salt impurities and can have lower calcium levels, or it can be extracted from natural sources like fishbone, coral, bovine bone, eggshell, and seashells.[3]
What are hydroxyapatite’s main benefits?
Hydroxyapatite is used in toothpaste to prevent cavities and reduce dentin sensitivity.[3] There’s not enough research to say how it measures up to fluoride.
As a dietary supplement, it has been used as a source of calcium to slow osteoporosis and for reducing osteoporosis-related pain. The forms found in dietary supplements include ossein-hydroxyapatite complex (OHC) and microcrystalline hydroxyapatite compound, both of which are sourced from powdered bone and contain bone proteins in addition to hydroxyapatite.[1][4][5]
Hydroxyapatite has also been formulated as an injectable skin filler that is FDA-approved to cosmetically treat wrinkles and facial fat loss in people with human immunodeficiency virus (HIV).[6]
What are hydroxyapatite’s main drawbacks?
No safety concerns have been reported for hydroxyapatite used in toothpaste.[3] In supplements taken by mouth, ossein-hydroxyapatite has been used in studies for up to four years without safety issues, while microcrystalline hydroxyapatite has been used for up to one year.[1][7] Common adverse effects are gastrointestinal (constipation, dyspepsia, abdominal pain, vomiting, etc) and seem to occur at a slightly lower rate than with calcium carbonate supplements.[8][1] Since hydroxyapatite dietary supplements are typically from bovine sources, improper manufacturing processes might increase the risk of variant Creutzfeldt-Jakob disease(vCJD), also known as “human mad cow disease”.[2][9][10]
How does hydroxyapatite work?
Hydroxyapatite provides the hardness and support of bones and teeth in the body. Teeth are made of 70% to 80% large hydroxyapatite crystals, which are organized by matrix proteins such as amelogenins and enamelins, providing a framework for mineralization and demineralization of enamel. In the bone, nano-hydroxyapatite crystals in the shape of needles and plates are organized by a network of type-I collagen, resulting in the structural stability and hardness of bones.[3] As a supplement, hydroxyapatite is a source of dietary calcium which reduces bone resorption, which is the body’s process of breaking down bones to ensure there is sufficient calcium in the blood. This contributes to increased bone mineral density and, theoretically, to stronger bones.[2]
What are other names for Hydroxyapatite?
Note that Hydroxyapatite is also known as:
- HAP
- Microcrystalline hydroxyapatite compound (MHC)
- Nanohydroxyapatite (nHA)
- Ossein-hydroxyapatite (OHC)
Hydroxyapatite should not be confused with:
- Tribasic Calcium Phosphate
Dosage information
In dietary supplements, ossein-hydroxyapatite and microcrystalline hydroxyapatite contain about 20-25% of elemental calcium by weight. Typical dosage of ossein-hydroxyapatite is two 830 mg tablets twice daily; each tablet contains 178 mg elemental calcium, for a daily total of 712 mg elemental calcium.[1] A typical dose of microcrystalline hydroxyapatite compound is eight 500 mg capsules; each capsule contains 125 mg elemental calcium, for a daily total of 1000 mg elemental calcium.[2]
In toothpaste, hydroxyapatite concentration is typically 10%.[3]
Frequently asked questions
What is hydroxyapatite?
What are hydroxyapatite’s main benefits?
Hydroxyapatite is used in toothpaste to prevent cavities and reduce dentin sensitivity.[3] There’s not enough research to say how it measures up to fluoride.
As a dietary supplement, it has been used as a source of calcium to slow osteoporosis and for reducing osteoporosis-related pain. The forms found in dietary supplements include ossein-hydroxyapatite complex (OHC) and microcrystalline hydroxyapatite compound, both of which are sourced from powdered bone and contain bone proteins in addition to hydroxyapatite.[1][4][5]
Hydroxyapatite has also been formulated as an injectable skin filler that is FDA-approved to cosmetically treat wrinkles and facial fat loss in people with human immunodeficiency virus (HIV).[6]
Is hydroxyapatite better than other calcium supplements for bone health?
There are some claims that, because hydroxyapatite contains other minerals and constituents from natural bone, it works better for bone health than other calcium supplements. However, there’s currently no convincing evidence to prove this. Studies have not found higher calcium absorption from osseo-hydroxyapatite or microcrystalline hydroxyapatite supplementation than from supplementation with other calcium salts, such as calcium citrate.[11][2]
A meta-analysis from 2009 of six small studies does suggest that taking osseo-hydroxyapatite results in a 1% greater bone mineral density (BMD) over 1-3 years compared to taking calcium carbonate.[1] However, this analysis is of limited use because of inclusion of unpublished studies, low study quality (e.g. lack of blinding), and possible presence of financial bias. Furthermore, a 1% increase in BMD over 1-3 years is not enough to prevent fractures, which are the key clinical outcome in bone health.[12]
What are hydroxyapatite’s main drawbacks?
No safety concerns have been reported for hydroxyapatite used in toothpaste.[3] In supplements taken by mouth, ossein-hydroxyapatite has been used in studies for up to four years without safety issues, while microcrystalline hydroxyapatite has been used for up to one year.[1][7] Common adverse effects are gastrointestinal (constipation, dyspepsia, abdominal pain, vomiting, etc) and seem to occur at a slightly lower rate than with calcium carbonate supplements.[8][1] Since hydroxyapatite dietary supplements are typically from bovine sources, improper manufacturing processes might increase the risk of variant Creutzfeldt-Jakob disease(vCJD), also known as “human mad cow disease”.[2][9][10]
How does hydroxyapatite work?
Hydroxyapatite provides the hardness and support of bones and teeth in the body. Teeth are made of 70% to 80% large hydroxyapatite crystals, which are organized by matrix proteins such as amelogenins and enamelins, providing a framework for mineralization and demineralization of enamel. In the bone, nano-hydroxyapatite crystals in the shape of needles and plates are organized by a network of type-I collagen, resulting in the structural stability and hardness of bones.[3] As a supplement, hydroxyapatite is a source of dietary calcium which reduces bone resorption, which is the body’s process of breaking down bones to ensure there is sufficient calcium in the blood. This contributes to increased bone mineral density and, theoretically, to stronger bones.[2]
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