Maintaining adequate calcium intake is important for bone and cardiovascular health. However, getting too much calcium, particularly from supplements, can be harmful, and has been associated with an increased risk of prostate cancer, kidney stones, and heart attack -- especially in post-menopausal women. Use of calcium supplements may increase the risk of dementia in elderly women who have evidence of cerebrovascular disease or who have a history of stroke. There is mixed evidence as to whether calcium from supplements increases the risk of age-related macular degeneration (AMD).

For women over age 50 and men over age 70, 1,200 mg is the recommended daily intake of calcium from food and supplements combined (for women under 50 and men under 70 it's 1,000 mg, while for older kids and teenagers it's 1,300 mg). If you can get most of it from food, then limit your calcium supplement to just the amount you need.  It is generally felt that calcium supplementation should not exceed 500 mg per dose and no more than 900 mg per day.  

More information about calcium, including amounts of calcium in foods and our tests of calcium supplements, is found in the Calcium Supplements Review >>

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August 3, 2014

One added thought: The calcium in SILK and Orange Juice is CaCO3, the same stuff as most supplements, thus really NOT a "food" source. Kale contains the most Calcium of all veggies, and it's absorbed from out gut; the Ca in Spinach is not aborbed due to oxalic acid content of this veg. BTW, these are two of highest Vitamin K content vegs. (See USDA SR-17 for breakdown of foods).

August 3, 2014

I think it's good that ConsumerLab is saying to not exceed 500mg Ca per serving. Studies seem to indicate that Supplemental CA increases the risk of calcium buildup in arteries, but that from foods does not do this.

I was diagnosed with Osteoporosis (tho' a husky male) in 1997, and tho' purposely avoiding fosamax and other bisphosphonates, managed to improve bone density rather than loosing it with increasing age (DEXA scan now @ 76 rates me as Osteopeia). This was accomplished with exercise, testosterone cypionate injections, supplemental calcium (I'm allergic to milk) and vitamin D3 (25 OH=60). Unfortunately a recent heart scan resulted in a coronary artery calcium score of 1350 or 75th percentile, a significant risk factor, but no symptoms. This with all green lipid results since 2006 on Berkeley and HDL panels.

My Endocrinologist is now telling me to get 1000 mg of Ca daily from food and supplements combined and to limit individual Ca doses. I've switched to the Forks over Knives whole plant foods diet to try to improve that calcium score in 2-3 years.

January 25, 2015

Docs and nutritionists argue over Calcium. A supplement of 1000 is an awful lot, because it would be added to what you get from your diet. Many docs (my buddies) throw calcium around like water. If you eat veggies, you get some calcium, and if you eat "tons" of red meat you may need extra calcium, as it is used to neutralize the acid made as the meat is digested. Increasingly recognized is that you need magnesium to go with your calcium, in relatively similar doses. But this is complicated. Vegetable foods have both minerals, maybe why calcium from food is not toxic, but from supplements calcium can increase heart disease. Magnesium comes in many different salts, and the cheapest oxide is poorly absorbed in many people, so use mag citrate or chloride or malate or taurate or glycerinate. Mg citrate can make the bowel loose, the others not as much. Magnesium has multiple beneficial effects on insomnia, tight muscles, cramps, restless legs, irritable mood, helps maintain blood pressure in normal range, migraines, and even seizures in pregnancy. (Now you see why we're trying to figure out the right balance between calcium and magnesium.)

May 28, 2020

I have celiac disease and find that when I take less than 1,500 mg of calcium supplements in a day, I feel sad and get cramps in the backs of my legs, just below the knee -- both of which are signs of low calcium. I take 2000 IU of vitamin D each day, so it's not that. I worry that 1,500 mg of calcium in a day is a lot and could be setting me up for heart attacks in the future, but I think the bottom line is that I need to listen to my body, and since I get symptoms of calcium deficiency when I don't take 1,500 mg a day, then it seems likely that 1,500 mg is right for me. But I worry.

May 27, 2015

I had Thyroid surgery years ago and after that was left with low calcium levels in my blood. For years I am taking very high doses of Calcium otherwise my fingers and legs are going to sleep. I am taking liquid Calcium. Is it better then regular calcium pills?
May 28, 2015

Hi Jolanta - As long as a calcium pill can properly disintegrate in solution (a test performs on all tablets and caplets), it should be as effective as a liquid supplement. You can see our test results for popular calcium supplements here:

August 27, 2015

I, also had parathyroid surgery (I believe you meant parathyroid, as those are the glands that control calcium levels in the body) and was on very high doses of calcium for almost a year. I had been maintaining on 1000--2000 mg calcium daily, but was looking for a more natural form of obtaining my calcium. I recently stopped taking my calcium and switched to an herb, yellow dock, which I was told was high in calcium. Within three weeks, I could barely move my legs. When I figured out what had happened, I immediately went back on my calcium and, within an hour, was back to normal. I, then, researched this herb and discovered that it can lead to hypocalcemia (low calcium). It was a very frightening experience. I am sticking to my calcium supplements.

March 19, 2017

I take a "One A day Men's" multivitamin a day. However, I take it every other day - about 3-4 days a week. My diet is pretty balanced so it's more for insurance purposes if you will.

It contains 200mg of Calcium elemental.

1) Even though I believe I consume adequate calcium in my this small amount of calcium from the multivitamin of concern?

2) Is elemental safer than carbonate?

Thank you.
March 20, 2017

Hi David - Taking it every other day is not a bad idea if you are just taking it as "insurance." As noted elsewhere, if you are definitely already getting the daily requirement of calcium, you don't need the 200 mg. If you are borderline, the 200 mg every other day should be fine. You can't actually take "elemental" calcium - it is always combined with another compound. Calcium carbonate is fine.

March 20, 2017

My calcium levels were tested and were in the Normal range.

If one is getting too much calcium from supplements or otherwise to where it could cause kidney stone or artery calcification issues, is this going to show up in blood work as ABOVE normal?
July 28, 2017

Hi David - You may not see a rise in your serum calcium level from taking calcium supplements, as our bodies typically do a good job at keeping levels fairly steady. However, there may be a significant increase in urine calcium levels (Samozai J Nutr Health Aging 2015 --

January 30, 2017

As for osteoporosis prevention and treatment the plant-based calcium like Algae Cal is pretty popular. At the Consumer Lab Calcium section I see information that such products can increase bone density by 1%-4% a year. Could you please inform which of these products is most effective and safe?
February 8, 2017

Hi Leonard - Please see this CL Answer:

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