calcium
Did you know there are over 8 different calcium chemical compounds sold as calcium supplements
There are 2 important things to keep in mind when looking at any mineral supplement, first what is the elemental percentage and second is bioavailability
Elemental Percentage
This is simply what percent of the compound is actually calcium. Some supplement’s chemical compound only contains 10% calcium while others are almost 90% calcium. Generally speaking, the higher the elemental percentage, the smaller the pill or the fewer pills there are to take
Bioavailability
Bioavailability is a measure of how much calcium is absorbed by your body. The bioavailability of a calcium supplements varies depending on its the chemical compound, its form (tablet, capsules, powders), other minerals present in the supplement, foods you eat with it, your age, and physical activity
Our key metric
Price Per Absorbed Gram
This allows you to see what the true cost is for each gram of calcium that your body actually uses.
Featured Products
Finding calcium supplements with high bioavailability and elemental percentage lowers the size and number of pills needed to meet the recommended daily allowance (RDA). When we consider what your body absorbs some of the more inexpensive supplements may not be the bargain they appear to be. While other supplements with higher prices may be absorbed much better allowing you take fewer (or smaller) pills.
Additionally, reviewing the possible side effects that may be heightened in one compound over another. Click on any of the compounds below to see the top-rated supplements within each compound
Our Picks for Top Calcium Supplements
Finding the best calcium compound for you can depend on a lot of things and vary depending on what you are looking to achieve. Bioavailability plays a role, as does elemental percentage. We’ve compiled the data for you, and here are our top calcium picks.
Below, please find a complete list all of the major supplement types.
Calcium Citrate Malate
- 40% bioavailability
- 26% calcium
- Water Soluble (easier on the stomach)
- There is some evidence of it being dissolved directly into cell membranes
- Treats Osteoporosis, Osteomalacia/Rickets, Hypoparathyroidism, and Latent Tetany
Calcium Orotate
- 90% bioavailability
- 10% calcium
- It is naturally found in the body
- Calcium ion is delivered directly to the center of the body’s cells
- Treats Osteoporosis, Osteomalacia/Rickets, Hypoparathyroidism, Latent Tetany, and has been found to help reduce muscle cramps and spinal pain, reduces the severity of insomnia and stress, and increases the ability to metabolize iron.
Calcium Citrate
- 35% bioavailability
- 21% calcium
- Recommended compound for those at risk for kidney stones since citrate is a natural inhibitor of stones (for those forming the most common calcium oxalate stones)
- Calcium citrate is less likely to cause constipation than many other forms of calcium
Bioavailability
15%
Calcium Carbonate
The most common and least expensive calcium supplement; seashells, shellfish, eggshells, pearls, rocks (like limestone) and even snails. Antacids frequently contain calcium carbonate. It contains a high percentage of elemental calcium but is not absorbed well by the body.
Possible side-effects:
- More Common – constipation, upset stomach, gas, and burping (allergic reactions for those with allergies to shellfish(skin rash, hives, swelling))
- Unlikely – confusion, irritability, headache, mental/mood changes, loss of appetite, weight loss, bone/muscle pain, changes in urination, and unusual weakness or tiredness
- Rare – allergic reaction (skin rash, hives, swelling)
Calcium Citrate
Calcium citrate has an acidic base which in turn allows better absorption than many other calcium compounds. This is due to the fact that the acidity of calcium citrate requires less production of stomach acids to digest. It does, however, have lower concentrations of calcium in the supplement at only 21%.
Possible side-effects:
- More Common – stomach upset and constipation
- Unlikely – changes in urination, nausea/vomiting, loss of appetite, weight loss, mental/mood changes, bone/muscle pain, headache, dry mouth, weakness, tiredness and pounding heartbeat
- Rare – allergic reactions (skin rash, hives, swelling, trouble breathing)
Bioavailability
35%
Bioavailability
40%
Calcium Citrate Malate
Calcium citrate malate is water soluble, which means it is more gentle on the stomach than other calcium compounds. It has a relatively high elemental percent of calcium, plus it has a high bioavailability. Some studies show evidence of calcium citrate malate being dissolved directly into cell membranes which is an added bonus.
Possible side-effects:
- More Common – constipation and stomach upset
- Unlikely – nausea/vomiting, loss of appetite, mental/mood changes, urination changes, bone or muscle pain, headache, increased thirst, weakness, tiredness, and pounding heartbeat
- Rare – allergic reaction (rash, swelling, trouble breathing)
Calcium Lactate
Produced by mixing lactic acid with calcium carbonate or calcium hydroxide. Calcium lactate is not, however, considered a dairy product, so those with dairy allergies should be safe. The food industry uses it as a thickener, a leavening or firming agent, and even a flavor enhancer. Mixing an organic acid with calcium increases the bioavailability, which is what is done to produce calcium lactate. If you compare the elemental percentage and the bioavailability of calcium carbonate and calcium lactate, you can see how effective that process is.
- More Common – stomach upset and constipation
- Unlikely – changes in urination, nausea/vomiting, loss of appetite, weight loss, mental/mood changes, bone/muscle pain, headache, dry mouth, weakness, tiredness and pounding heartbeat
- Rare – allergic reactions (skin rash, hives, swelling, trouble breathing)
Bioavailability
30%
Bioavailability
20%
Calcium Gluconate
Calcium gluconate is water soluble but has a very low percentage of actual calcium (only 9%). The bioavailability isn’t much better at only 20%. [sub_nutrient_description]calcium gluconate[/sub_nutrient_description]
Possible side-effects:
- More Common – stomach upset and constipation
- Unlikely – changes in urination, nausea/vomiting, loss of appetite, weight loss, mental/mood changes, bone/muscle pain, headache, dry mouth, weakness, tiredness and pounding heartbeat
- Rare – allergic reactions (skin rash, hives, swelling, trouble breathing)
Calcium Orotate
Calcium Orotate is made with the mineral salts of orotic acid. Most living things naturally have small amounts of calcium orotate in their systems. In fact, both plants and animals use it in their RNA and DNA. It is a primary mineral (naturally found in the body) for the creation of bones and teeth. Studies have shown calcium orotate is able to penetrate cell membranes rising the bioavailability of this calcium compound far above all the rest. Not only does it treat osteoporosis effectively, but is also prescribed more than other compounds for those with low blood calcium levels. These calcium compound supplements have also been found to reduce muscle cramps, reduce pain associated with the spine, helps with insomnia, reduces stress, and increases the ability to metabolize iron.
Possible side-effects:
-
More Common – stomach upset and constipation
-
Unlikely – changes in urination, nausea/vomiting, loss of appetite, weight loss, mental/mood changes, bone/muscle pain, headache, dry mouth, weakness, tiredness and pounding heartbeat
-
Rare – allergic reactions (skin rash, hives, swelling, trouble breathing)
Bioavailability
90%
Bioavailability
15%
Calcium Phosphate
Calcium Phosphate occurs naturally in our tooth enamel and bones as well as some rocks, and animal bones. Besides being used as a supplement, it is also used as a fertilizer, in dentifrices, baking powder and also as a food additive. The bioavailability is very low at only %15 and with higher an elemental percentage of 35%, it makes this supplement less effective than most… slightly better than calcium carbonate.
Possible side-effects:
-
More Common – stomach upset and constipation
-
Unlikely – changes in urination, nausea/vomiting, loss of appetite, weight loss, mental/mood changes, bone/muscle pain, headache, dry mouth, weakness, tiredness and pounding heartbeat
-
Rare – allergic reactions (skin rash, hives, swelling, trouble breathing)
Oyster Shell Calcium
Oyster Shell Calcium is a natural source of calcium is simply a form of calcium carbonate. Some claim it is absorbed better than other forms of calcium carbonate which are sourced from limestone. It has a low elemental percentage as well as low bioavailability. In rare cases oyster shell calcium supplements have been known to contain levels of lead toxins.
Possible side-effects:
-
More Common – stomach upset and constipation
-
Unlikely – changes in urination, nausea/vomiting, loss of appetite, weight loss, mental/mood changes, bone/muscle pain, headache, dry mouth, weakness, tiredness and pounding heartbeat
-
Rare – allergic reactions (skin rash, hives, swelling, trouble breathing)
Bioavailability
15%
Calcium Compound Summary
| Compound Name | Elemental % | Bioavailability |
| Calcium Carbonate | 40% | 15% |
| Calcium Citrate | 21% | 35% |
| Calcium Citrate Malate | 26% | 40% |
| Calcium Gluconate | 9% | 20% |
| Calcium Lactate | 13% | 30% |
| Calcium Orotate | 10% | 90% |
| Calcium Phosphate | 35% | 15% |
| Oyster Shell Calcium | 10% | 15% |
Elemental % indicates what percent of the compound is actually calcium. (Supplement labels should indicate how much elemental calcium is present in each serving, not how much of the compound is present.)
Bioavailability is an estimated percentage of the amount of the elemental calcium that is absorbed by an average person.
Recommended Dietary Allowance
The Recommended Dietary Allowance (RDA) is “the amount of an essential nutrient, as a vitamin or mineral, that has been established by the Food and Nutrition Board of the National Academy of Sciences as adequate to meet the average daily nutritional needs of most healthy persons according to age group and sex.” –- dictionary.com
We used the RDA for calcium from the National Institutes of Health – Office of Dietary Supplements listed below.
|
Age |
Male Daily |
|
0-6 months |
200 mg |
|
7-12 months |
260 mg |
|
1-3 years |
700 mg |
|
4-8 years |
1000 mg |
|
9-18 years |
1300 mg |
|
19-50 years |
1000 mg |
|
51-70 years |
1000 mg |
|
71+ years |
1200 mg |
|
Age |
Female Daily |
|
0-6 months |
200 mg |
|
7-12 months |
260 mg |
|
1-3 years |
700 mg |
|
4-8 years |
1000 mg |
|
9-18 years |
1300 mg |
|
19-50 years |
1000 mg |
|
51+ years |
1200 mg |
| Life Stage | Age | RDA |
| Pregnancy | 13-19 years | 1300 mg |
| Pregnancy | 20+ years | 1000 mg |
| Breast-Feeding | 13-19 years | 1300 mg |
| Breast-Feeding | 20+ years | 1000 mg |