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Is Calcium Hydroxyapatite Safe To Take?

Updated: Jan 19

Calcium hydroxyapatite is a type of supplement, which can be taken to meet the daily recommended intake for calcium. People aren't always able to get in their required amount from natural sources and that is where this supplement comes in.

NOW foods calcium hydroxyapatite
NOW foods calcium hydroxyapatite

Table of contents:


What is calcium hydroxyapatite made of?

One way to understand whether or not a compound is safe or not is by looking at its individual components. The molecular formula for calcium hydroxyapatite [Ca10(PO4)6(OH)2] gives us a hint as to what it is made of.

It's literally composed of calcium and phosphates, both of which are naturally found in food sources. They also happen to be very important minerals for keeping your bones and your teeth healthy. In other words, they're as safe as you can get.


Calcium is certainly not harmful because it is a necessary mineral for building strong bones and teeth. In fact, the vast majority of the population happens to be calcium deficient because they don't get enough of it in their diet.

Drinking milk has always been a great source of getting more of this nutrient into your body. You can also find it in most dairy products such as cheese and even fortified milks.

Recommended daily intake:

  • Women 19-50 = 1000 mg; Women 51+ = 1200 mg; Pregnant/Lactating = 1,000 mg

  • Men 19-70 = 1000 mg; Men 71+ = 1,200 mg


When we think of strong bones, calcium comes to mind but phosphates are required in order for the bone mineral to be complete. After all, the bone mineral is hydroxyapatite and it is not calcium alone that makes up all of it. Without phosphates you'll have an incomplete structure.

Dairy tends to be a fairly good source for phosphorus along with proteins like beef, poultry, pork, and salmon. You'll also find them in vegetables and whole grains as well.

Recommended daily intake:

  • Women 19+ = 700 mg

  • Men 19+ = 700 mg


What makes it safe to take?

What makes calcium hydroxyapatite safe to take is the fact that it is highly biocompatible and biomimetic since it is identical to what our teeth and bones are made of. Due to its similarities, it is non-toxic and there have never been any reported allergies.

This calcium supplement is perfectly safe to take, ingest, and use since it is essentially made of calcium and phosphorus. There is nothing toxic about any of these individual mineral components which it is made out of. They are technically vital supplements that are essential for human survival.

No reported allergies

It is technically impossible for you to be allergic to calcium hydroxyapatite since our bones and teeth are made of it.

  • Bones consist of 60% of it by weight.

  • Enamel consists of 97% and dentin 70% by weight.

If you were allergic to it, you would be permanently itchy all of the time since your skin, lips, and tongue are in contact with hydroxyapatite at all times. Essentially you would be allergic to your own being.

Nonetheless, the allergenicity of calcium hydroxyapatite have been tested and no adverse skin reactions were found. According to studies, it turns out that hydroxyapatite cannot possess immunotropic nor allergenic characteristics. That makes sense since we wouldn't have teeth or bones otherwise.

Benefits of taking it

If you're not intaking enough calcium, it is actually more dangerous to NOT take a supplement such as calcium hydroxyapatite. A lot of bodily functions rely on having sufficient calcium such as your bones and your teeth. When you are deficient in it, your bones and your teeth will start to weaken.

Studies have shown that there is a direct correlation between how much calcium you take and your risk for fracturing bones.

  • There is a 280% increase in fracture risk if you take less than 800 mg/day.

  • There is a 85% decrease in fracture risk if you take more than 800 mg/day.

calcium intake on fracture risk graph

Calcium also helps to keep your teeth healthy because it is used to build and repair them. Studies have shown that even if you use a remineralizing fluoride toothpaste, a limiting factor is often the quantity of calcium and phosphates in saliva.

However if you use a different remineralizing toothpaste such as nanohydroxyapatite, you may be able to circumvent that deficiency in minerals. Reason is because it already contains all of the calcium and phosphates that you need in it!


What happens when you swallow calcium hydroxyapatite?

Absolutely nothing bad happens if you happen to swallow it. The calcium hydroxyapatite simply dissolves into its individual mineral components when it comes into contact with stomach acid.

The chemical reaction that occurs when hydroxyapatite encounters acid whether in the mouth or in the stomach: Ca10(PO4)6(OH)2 + 8 H+ → 10 Ca2+ + 6 HPO42- + 2 H2O

Essentially the entire compound breaks up into calcium, phosphates, and water. All of which are harmless and non-toxic. These minerals get absorbed by the body once it passes through the stomach and into the intestines. Then it gets routed to your bones and teeth to be used as building blocks for making them stronger.

Due to the fact that hydroxyapatite is non-toxic, it is one of the reasons why it is recommended over fluoride toothpastes for children. If children swallow the nano-hydroxyapatite, it is not harmful but if they swallowed the fluoride one, you'd be in trouble.

This happens on a daily basis with your teeth

There is no need to be concerned about ingesting the hydroxyapatite because you do it all the time with your teeth. When you consume a lot of sweets or anything acidic, the acid will attempt to dissolve your enamel via a process called demineralization.

demineralization remineralization of teeth
Credit: Sangi Co

The acid will pull the calcium and phosphates out of the hydroxyapatite in your enamel. Most of which you'll most likely end up swallowing. That is essentially what happens whenever you start developing a cavity. Most people have had cavities and the unfortunate ones have had multiples.

Since you were fine from the cavities, you're most likely going to be okay from taking these calcium supplements since they're identical.


Is it the best source of calcium?

Unfortunately according to studies, taking calcium hydroxyapatite is NOT the best source of calcium. That is not because it is an illegitimate source for the mineral but rather it has to do with how well it gets absorbed on its own.

The mineral calcium is fat soluble and the body needs vitamin D to help absorb it. It gets actively absorbed in the small intestine whenever vitamin D is present. Without any of the vitamin, you won't be able to get as much out of the supplement as you otherwise could.

Due to this reason, the recommendation from nutritionists have always been to try to get as much of your calcium from whole foods sources as possible. This is why milk tends to be a fantastic choice for reaching your daily quota since it has fats and vitamin D in it.

kefir whole milk lifeway

However that doesn't mean that calcium hydroxyapatite is a failure as a supplement. You will still get calcium out of it even if you take it on its own but just not as much. It is simply not easily absorbed on its own.

Nonetheless, you can increase the effectiveness of it if you take it with a meal that has fats and vitamin D. Those will assist your body in helping you take in more of it by absorbing it more easily.


The Verdict

Calcium hydroxyapatite is safe to take as a supplement because our bones and teeth are practically made of it. It is highly biocompatible and is non-toxic in nature. The only effect which occurs if you swallow it is it helps you build stronger teeth and bones which our dentists in Long Island City support.

Despite it being harmless, it is actually not the most efficient source of calcium. The general consensus is to try to get your minerals from whole foods instead of supplements because it gets absorbed better. Taking the supplement on its own typically leads to lower absorption rates when compared to foods.

Reason is due to the fact that calcium is a fat soluble mineral whose absorption gets enhanced by the presence of vitamin D. In other words, milk is a great alternative! However if you really can't get enough of this mineral in your diet, the supplement is helpful to take. You can make it more effective by taking it with a meal that contains fats as well as vitamin D.


David Chen 200 x 200.jpg

About the author: Dr David Chen, DDS

Hello, I'm Dr Chen and I'm an actively practicing dentist in Long Island City, NY. I graduated from Columbia University College of Dental Medicine in 2016 but prior to going to dental school I was already working in the dental field. It's been more than a decade since I first got to know dentistry and let me tell you, time flies by quickly. Since then I've developed a fondness for writing, which is how this all got started!

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Medical Disclaimer:

This blog is purely meant for information purposes and should not be used as medical advice. Each situation in your mouth is unique and complex. It is not possible to give advice nor diagnose any oral conditions based on text nor virtual consultations. The best thing to do is to go in person to see your dentist for an examination and consultation so that you can receive the best care possible.

The purpose of all of this oral health information is to encourage you to see your dentist and to inform you of what you may expect during your visit. Due to the unfortunate nature of dentistry, there isn't really any true home remedies that will get rid of dental problems. Roughly 99.99% of them require in-person intervention by a healthcare professional.

Hint: That is the reason why you can't eliminate seeing dentists in your life!

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