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Best calcium supplement

Which calcium supplement is best?

Taking calcium for strong bones may be a no-brainer but not all calcium supplements are of equal value. Plus, your age is a factor in how much calcium you should take. Some supplements may also include added vitamins, such as vitamin D or magnesium, to improve absorption.

Calcium supplements not only help strengthen bones but also support your heart, muscles and nerves. For vegans and vegetarians, or for those who prefer organic supplements, Garden of Life MyKind Organics Plant Calcium is the top choice. 

What to know before you buy a calcium supplement

Types of calcium

There are a few different types of calcium available in supplement form. All are in compound form. This means that the calcium is attached to other atoms. You'll want to pay attention to what percentage of the compound contains actual calcium (called elemental calcium). 

  • Calcium carbonate contains 40% elemental calcium. This is the cheapest and one of the most common calcium compounds used in supplements. While it has a high concentration of calcium, it can cause stomach upset. The stomach has to produce more acid to absorb this type, which may cause gas, bloating and constipation.
  • Calcium citrate contains 21% elemental calcium. It is another common and inexpensive calcium compound. While its percentage of pure calcium is lower than calcium carbonate, it is easier on the stomach. 
  • Calcium gluconate contains 9% elemental calcium. It is mostly used by physicians intravenously to treat conditions such as hypocalcemia and too much magnesium. It’s not as popular in supplement form because it contains such a low amount of elemental calcium.
  • Calcium lactate contains 13% elemental calcium. It has good bioavailability but you’ll have to take more of it to match the amount of calcium in the other types. One of the benefits of calcium lactate is that you can take it on an empty stomach. 


The majority of calcium supplements come in pill form, either capsules, softgels or tablets. If you have trouble swallowing pills, you can also find calcium in liquid, chew or powder form. 


The recommended daily allowance (RDA) of calcium is 1,000 milligrams per day for adults ages 19-50. For women aged 51-70, 1,200 mg is the RDA while only 1,000 is the RDA for men in that age group. For all adults over 70, 1,200 mg a day is recommended. Pay attention to the serving size, which is the number of pills or scoops required to get the full dose of calcium.   

Tolerability and precautions 

Calcium supplements can cause constipation, especially calcium carbonate. You may need to try a few types to see what you can tolerate. Calcium citrate can be taken on an empty stomach and is recommended for people with low stomach acid, such as individuals aged over 50 or who are taking acid blockers.

Calcium supplements can interact with many different prescription medications (such as blood pressure medications and antibiotics) as well as supplements, so ask your health care provider before starting supplementation. 

What to look for in a quality calcium supplement

Added minerals

Calcium can reduce the absorption of magnesium, zinc and iron. Select supplements contain added magnesium and/or zinc. If you take an iron supplement, take your calcium one at least two hours before or after the calcium supplement. 

Added vitamins 

To absorb calcium, your body needs vitamin D. If you’re not getting enough vitamin D through the sun or food, choose a calcium supplement with added D, or even better, D3. Select calcium supplements also contain added vitamin K2, which directs the calcium to its proper place. 


If you’re on a plant-based diet, be sure your supplement is labeled vegan. Algae calcium is a newer plant-based supplement that's popular. The majority of supplements with added vitamin D are not vegan. Capsules that contain gelatin are not vegetarian. 

How much you can expect to spend on a calcium supplement

Expect to pay between 5-25 cents per pill. Algae and plant-based forms of calcium cost between 16-68 cents per pill. 

Calcium supplement FAQ

Should I take a calcium supplement derived from oyster shells or bone meal?

A. While these forms of calcium are advertised as being natural, we don’t recommend taking them due to their high concentrations of heavy metals, such as lead, which can be toxic. 

What does bioavailability mean?

A. A supplement’s bioavailability means how much of the calcium (or other nutrients) are absorbed by the body. It’s measured by the proportion of the element that enters the bloodstream. 

What’s the best calcium supplement to buy?

Top calcium supplement

Garden of Life MyKind Organics Plant Calcium

What you need to know: A top-of-the-line organic supplement, this plant-based calcium is sourced from real foods and doesn’t contain animal products. 

What you’ll love: The tablets contain vegan vitamin D3, vitamin K and magnesium. It’s sourced from algae, fruits and vegetables — not from crushed stones like most calcium supplements. It’s certified organic and vegan. 

What you should consider: To get the full dosage, you have to take this three times a day and the vegan tablets are pricey. 

Where to buy: Sold by Amazon 

Top calcium supplement for the money

Nature’s Bounty Calcium 

What you need to know: This low-cost calcium softgel is easy to swallow and contains vitamin D3. 

What you’ll love: People report a decrease in muscle cramps after taking these regularly. The gelcaps are easy to swallow for most. They provide the right amount of calcium for older adults concerned with osteoporosis, and many report improvement in their bone density conditions. 

What you should consider: Some reviewers complain that the serving size is two softgels a day for 1200 mg of calcium, instead of just one pill. 

Where to buy: Sold by Amazon

Worth checking out

New Chapter Calcium Supplement 

What you need to know: This vegetarian calcium tablet is slim and offers slow release for better absorption. 

What you’ll love: The tablets are small but include vitamin D3 and vitamin K2. Derived from Red Marine Algae, the calcium source naturally includes magnesium. People report improvement in bone density, if not a reversal of osteoporosis conditions, from taking this. 

What you should consider: These plant-based tablets may cause nausea upon first taking them. They are also pricey. 

Where to buy: Sold by Amazon 

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Ana Sanchez writes for BestReviews. BestReviews has helped millions of consumers simplify their purchasing decisions, saving them time and money.

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