Calcium Hydroxyapatite vs Calcium Citrate | What's the Difference?

Calcium is a crucial mineral that promotes the development of sturdy bones and teeth. The human body comprises calcium and other minerals, including phosphorus, sodium, magnesium, sulfur, and chloride.


    Key Takeaways

  • Two calcium supplements are calcium citrate and calcium hydroxyapatite.
  • The most popular calcium supplement is calcium citrate, though some also use the more recent calcium hydroxyapatite form.
  • Calcium citrate may cause heartburn in some people who take it with meals, but this side effect isn't common with calcium hydroxyapatite.
  • Calcium supplements offer safe blood calcium levels if you take them as directed by your doctor or pharmacist.



Calcium is a crucial component in forming bone tissue and teeth enamel. It's also necessary for regulating blood pressure levels in our bodies by balancing out the effects of sodium (salt). Find out calcium citrate vs calcium hydroxyapatite and how they compare. We at Dr. Brite advise on what’s best as Dr.Brite's oral care products are plant-based and free from toxins. 

Taking pills out of the bottle

Calcium Hydroxyapatite vs Calcium Citrate

Calcium citrate is a form of calcium. When you hear someone say “calcium,” they usually refer to the mineral that makes up our teeth and bones. However, calcium hydroxyapatite is an alternative calcium form that is morebioavailable and better suited to your body's needs.

Three popular calcium supplement forms are calcium citrate, hydroxyapatite, and calcium carbonate. The mineral calcium is crucial for healthy bones and the prevention of osteoporosis. In the United States, calcium supplements are most frequently found in calcium citrate, though hydroxyapatite and carbonate are also available.

Calcium Citrate

Calcium citrate contains calcium and citric acid, a natural preservative derived from citrus fruits. This form of calcium is commonly used in antacids to treatindigestion, heartburn, and other conditions. Calcium citrate, which facilitates calcium absorption, is available as tablets and capsules.

Calcium citrate

Calcium Hydroxyapatite

Calcium hydroxyapatite contains calcium. Dr. Brite defines Hydroxyapatite as a naturally occurring mineral found in teeth and bones. It is often used for bone grafting procedures because it has a similar composition to bone tissue. Calcium hydroxyapatite is also used in cosmetics such as hydroxyapatite toothpaste and hair products. Calcium intake strengthens weakhair shaftsby making them more flexible and resistant to breakage when combed or brushed.

Which Is Better, Calcium Citrate or Calcium Hydroxyapatite?

If you're taking dietary calcium supplements, it's essential to find the most absorbable form.

The best source of calcium supplements is food. However, if you need more from your diet, your doctor may recommend taking a supplement containing calcium citrate or hydroxyapatite as the main ingredient.

Both are sources ofsupplemental calcium, but which is better? Calcium citrate has a higher absorption rate than hydroxyapatite (71% vs 46%), making it more efficient in terms of how well it gets into your bloodstream and works to neutralize acidity levels in cells throughout the body. It also doesn't leave abad taste in the mouth as other forms do; plus, it's cheaper than different types!

Pills on a table

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Which Form of Calcium Is Best Absorbed?

The answer to this question is calcium citrate. The form of calcium has a higher bioavailability than hydroxyapatite, meaning it's easier for the body to absorb.

  • Calcium citrate is also less likely to cause side effects like constipation and bloating than hydroxyapatite, making it more convenient for supplement use.
  • Calcium hydroxyapatite is harder to absorb but has more calcium.
  • Calcium citrate is the more digestible option but contains less calcium. On the other hand, calcium hydroxyapatite is harder to absorb but provides more calcium per gram.
  • Calcium citrate is cheaper and easier to find than its counterpart. Calcium hydroxyapatite may be better suited for those with poor digestion or absorption of nutrients because it contains more calcium per gram than the other form.

Is Calcium Hydroxyapatite Easily Absorbed?

Not all calcium is created equal. While all three forms—calcium citrate, hydroxyapatite, and carbonate—contain the same amount of elemental calcium (1 gram), there are differences in how much your body absorbs calcium when you take each form.

Calcium hydroxyapatite is more complicated to absorb than calcium citrate or carbonate. Hydroxyapatite is more bioavailable thancarbonate but isn't as easily absorbed as citrate or other chelated forms of calcium. They both contain 1 gram per serving.

An older woman taking pill suplements

What Is Elemental Calcium?

Elemental calcium is the purest form of calcium that you can find, and it's available in various foods. Calcium is an essential mineral that helps build bones and teeth. It also plays a role in blood clotting, muscle contraction, and many other body functions.

Calcium is present in all animal products, such as milk, cheese, yogurt, and green vegetables, such as broccoli or bok choy (Chinese cabbage). It's also present in nuts such as almonds or Brazil nuts; seeds like sesame seeds; soybeans; wheat germ; sunflower seeds; corn kernels; dried fruit like apricots or raisins; oranges; pineapple juice; tea with lemon juice added; seafood such as clams or oysters; beans (black beans or navy beans); molasses.

Calcium citrate is one of the most popular forms of calcium because it's well-absorbed by most people. Calcium citrate has been widely used for decades to prevent bone loss during menopause because it doesn't causestomach upset or constipation. In addition, studies show that taking at least 1,200 mg/day of elemental calcium from supplements or fortified foods can help maintain normal kidney function in people with chronic kidney disease.

What Are Calcium Salts?

Calcium salts come in a variety of forms, including:

  • Calcium citrate—is more soluble than calcium carbonate and calcium phosphate
  • Calcium gluconate—solubility decreases when ionized (as from stomach acid)
  • Calcium lactate—is usually used with other ingredients, such as malic acid or sodium bicarbonate. In the U.S., they get labeled as “calcium malate,” “calcium malic acid complex,” or “calcium malate.”


Calcium salt in a wooden bowl

    Where Does Calcium Come From?

    Calcium is essential for maintaining healthy bones, teeth, and other bodily processes. Calcium supplements are frequently recommended for people with trouble getting enough calcium in their diet.

    Calcium comes from three sources:


    Calcium is found naturally in many dairy products, green leafy vegetables (collards, turnip greens), canned sardines and salmon with bones, tofu made with calcium sulfate, almonds, cocoa, and oyster shell calcium.


    Calcium supplements are available in various forms, including calcium citrate and calcium carbonate. These are sometimes taken together with vitamin D to make up for any deficiencies in your diet.


    Doctors sometimes give patients intravenous (IV) infusions of calcium gluconate or other IV injections to treat specific health problems that cause low blood levels of calcium.

    Intravenous (IV) infusions

      So Which One Is Better?

      The answer to that question is still up for debate. Experts claim that one form is better than the other, while others think it depends on your personal needs and preferences. But at the end of the day, calcium citrate and hydroxyapatite are excellent choices —and you should choose whichever works best for you!

      Frequently Asked Questions

      1. Can I Take Calcium Citrate with Other Vitamins and Supplements?

      Yes, you can take calcium citrate with other vitamins and supplements. However, you can only take the combination as long as they do not contain iron or magnesium. It is because calcium citrate can interact with these minerals to form insoluble salts that will be eliminated through the feces instead of absorbed into the body. Therefore, fewer nutrients will be available for your body to use.

      2. Is There Any Difference Between the Two Types of Calcium Supplements?

      There are several differences between calcium carbonate and calcium citrate, including price and absorption.

      In contrast, calcium carbonate is less expensive per milligram of elemental calcium, with a lower absorption rate than calcium citrate. Therefore, it is challenging to determine precisely how much essential calcium you are getting from your supplement if it contains both forms of this mineral.

      3. Are All Calcium Supplements the Same?

      No, all calcium supplements are not the same. Products labeled as “calcium carbonate” or “calcium citrate” are not always made the same way and may vary significantly in their bioavailability (how easily yourbody absorbs calcium). These two forms of calcium aren't created equal – some are better than others for bone health, and some will cause stomach issues and constipation.

      4. Can I Take Both at The Same Time?

      Yes, you can take calcium hydroxyapatite and calcium citrate simultaneously. Both are different forms of calcium supplementation that one may take simultaneously. However, if you are taking them both together, you will only need to take one pill per day instead of two.