In general, it appears to be preferable to get most of your calcium from foods which contain it naturally, and to restrict the amount you get from supplements (including calcium-fortified drinks and foods like orange juice, soy milk, almond milk, and even calcium-fortified milks like certain lactose-free milks — which are like taking a supplement with food). (A common form of calcium added to these beverages, as well as to gummy and liquid supplements, is calcium phosphate or tricalcium phosphate.) For example, getting too much calcium from supplements has been associated with an increased risk of kidney stones, heart attack and death in women, and an increase in the risk of heart attack in men. Taking calcium supplements has also been associated with an increased risk of dementia in elderly women who have evidence of cerebrovascular disease or who have a history of stroke. Nevertheless, calcium from all sources counts toward the upper tolerable intake level (UL) above which the risk of adverse effects increase — although it is rare to exceed this limit from food alone. 

If you are considering taking a calcium supplement, be sure to calculate how much calcium you are already getting from food, and from other sources, such as over-the-counter antacids, and then only supplement with the amount you need to meet the recommended daily intake. For more about getting the right amount of calcium, sources and different forms, and our tests of popular products, see the Calcium Supplements Review >>

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January 13, 2016

What about "food-based" calcium, such as Garden of Life's MyKind line, or MegaFood? Is that more similar to getting calcium from food? Thanks!
February 8, 2016

Hi Chris - You can find information about food-based calcium in the Calcium Supplements Review (, as well as our tests of a food-based calcium supplement (

December 20, 2015


Are you aware of a multi-vitamin you've tested that does not contain calcium carbonate? I get enough calcium from my diet and generally eat a well-balanced diet so I only take a multivitamin on a few non-consecutive days per week for insurance. I currently use the Bayer One-A-Day but it contains calcium carbonate.
December 31, 2015

Hi David - Are you looking for a multivitamin that does not contain calcium, or just a form other than calcium carbonate?

With the exception of one pre-natal product, all of the multis we tested do contain some form of calcium. Although many contain calcium carbonate, several contain a different form (such as D-calcium pantothenate or calcium ascorbate).

You can click on "Ingredients" underneath each product name (in the first column of the results table) in order to view the list of ingredients for each product, which includes the form of calcium used.
August 26, 2015

Thank you Jeanette and Kim for your questions! We've now added a new CL Answer about AlgaeCal here:

August 24, 2015

Can you kindly include review of other forms of calcium eg., AlgaeCal and Eggshell calcium?

I had been taking good Calcium Citrate for more than 10 years but still get osteopenia a few years back.
I switched to Nature City's TrueOsteo Advanced Bone Support as recommended by Dr Vivian Goldsmith of Saveourbones. TrueOsteo uses Algae Cal.
After almost 2 years on that my bone density tests showed some improvements instead of further deterioration. I'm now in my late 60's.
Thank you.

July 28, 2016

I think algae calcium is a good supplement. My doctor recommended Ca citrate because of better absorption into the blood stream vs. Ca carbonate. I have improved my bone density by about 5% a year. I am in my 70's. Sam's sell Ca citrate petite for a reasonable price. The petite means the tablets are smaller and easier to swallow. I take three a day. In September I take another Dexa scan. Hopefully it will increase. I am borderline osteoporesis.

August 24, 2015

This article makes sense to me. Years ago I was told that I have osteopenia. On and off for a while after being diagnosed I search the internet about osteopenia. After going through all the articles I came to the conclusion exactly what this article states.

August 23, 2015

My question is, what about the supplements that say they are "food-sourced" (from algae) calcium. Do they have the same issues as say, calcium citrate? That's not exactly like getting your calcium from something like kale - or is it?

August 23, 2015

Are the RDA figures for calcium in elemental form or in combination with other nutrients, such as Calcium Lactate or Calcium Citrate?
September 10, 2015

Hi Dave - The recommended daily intake is for elemental calcium only, not the entire compound.

February 8, 2017

Some unanswered questions exist about the negative effects of calcium supplements. The specific calcium complex may make a difference as might timing as might intake levels of other nutrients. For instance, taking calcium citrate before or between meals may spike blood calcium levels, which may be harmful. Taking the calcium at the end of a meal may not have the same effect. Also, taking calcium carbonate chronically may have antacid effects that may not be desirable in everyone. In addition, taking a lot of supplemental calcium may inhibit absorption of other nutrients such as magnesium (unless a person eats enough magnesium to overcome this). Lastly, it should be noted that the studies claiming harmful effects of calcium supplements can be interpreted multiple ways and are contradicted by some other studies.

Dr Robert DiSilvestro, Professor of Human Nutrition, Author of CRC Press Handbook of Minerals as Nutritional Supplements
February 8, 2017

Hi Dr. DiSilvestro - Yes, those are good points and these are discussed in detail in the Calcium Supplements Review ( It's worth clarifying that calcium’s effect on magnesium absorption is an issue when the two are taken at roughly the same time but not at different times of day.

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