She is a registered dietitian nutritionist, certified diabetes care, and education specialist. Casey is the founder of a private practice, Casey Seiden Nutrition, specializing in a non-diet approach to diabetes care and women’s health. She works with individuals, partners with companies, writes for media outlets, and is a published cookbook author.
Meredith Bull, ND, is a licensed naturopathic doctor with a private practice in Los Angeles, California.
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Calcium is the most abundant mineral in the body. and many people in the US don't consume enough of it. Calcium is "most known for its role in bone health, but it's also essential for blood clotting and the proper functioning of the muscles, heart and nerves,” says Anya Rosen MS, RD, LD, CPT, a virtual functional medicine practitioner.
If you can, try to meet your calcium needs through food rather than a supplement. The food group containing the most calcium is dairy, which includes yogurt, cheese, and milk. Other top food sources of calcium are canned sardines and salmon with bones, soy milk and tofu, chia seeds, and green vegetables.
If you have a deficiency, have absorption issues due to a health condition, or you follow a diet that limits or eliminates dairy, you may benefit from supplementation. If you do not fall into one of these groups, however, research is less clear on the benefits of taking a calcium supplement. If a healthcare provider has recommended you take a calcium supplement, talk to them about the ideal form and dosage for you. Additionally, look for a calcium supplement that also contains vitamin D, as these two nutrients work together and increase the amount of calcium your body can utilize.
Always speak with a healthcare professional before adding a supplement to your routine to ensure that the supplement is appropriate for your individual needs and which dosage to take.
The bottom line is that not everyone needs a calcium supplement, but some people may benefit from taking one. A calcium supplement does not make up for other factors that contribute to strong bones and overall health. It is important to eat an adequate and nutritious diet (being underweight is a risk factor for poor bone health and increased mortality) and exercise regularly. Smoking and excessive alcohol consumption can also contribute to weaker bones and other health issues.
Calcium is an important mineral for all people to consume, but some groups require more of it or are more at risk for calcium deficiency.
People with malabsorption conditions, such as inflammatory bowel disease and other diseases or previous surgeries affecting the intestines
People who use steroids may need a calcium supplement, as steroids can affect how your body uses calcium and vitamin D and can lead to bone loss.
Adolescent girls may benefit from a calcium supplement. Bone growth starts before birth and continues until age 20 to 25 years old, so early intake of calcium is important. For girls, increasing intake of calcium-containing foods and potentially adding a calcium supplement may help build bones and prevent or delay osteoporosis later in life.
Postmenopausal women may or may not benefit from a calcium supplement. After age 25 to 30, bones tend to get weaker. Postmenopausal women specifically have a higher risk of bone fractures because of changing hormone levels which causes bones to “shed” calcium. Increased dietary calcium may be beneficial during this time, and a supplement may or may not be helpful.
Those with diets low in calcium, such as many folks following vegan diets, will benefit from taking a calcium supplements or consistently consuming calcium-fortified foods.
Those who get enough calcium from food: Again, a supplement would be to complement dietary calcium intake, so it’s important that your total intake does not go over the upper limit, which ranges from 2,000 to 3,000 milligrams per day, depending on your age. Over supplementation of calcium may cause constipation, lead to kidney stones or kidney damage, and even contribute to cardiac and respiratory failure.
Those with kidney stones: If you have a history of kidney stones or heart disease, you should consult with your doctor before beginning a calcium supplement.
Those taking levothyroxine: Calcium supplements can also interfere with the absorption of thyroid hormones, so those taking levothyroxine (Synthroid) there would need to leave a time gap between taking these two pills.
Those taking antacids: If you frequently take antacids, such as Tums, exercise caution when supplementing with calcium as well.
Some people may need more than one serving
Bayer is known for high quality supplements, and their petite calcium pills do not disappoint. A top consideration for many people when taking and sticking with a supplement regimen is the ease of taking the supplement, which is usually connected to the size and number of pills. Compared to other calcium pills, Citracal Petite are narrower in size and coated for easier swallowing that doesn’t leave a chalky taste in your mouth. For adults who have difficulty swallowing, or someone who is already taking numerous other large pills—for example, in pregnancy—a smaller size and dose may make it easier to take them regularly.
We also like that Citracal Petites contain the digestive-friendly form, calcium citrate, so you’ll worry less about constipation. Their petite size and the fact that the total dose of calcium is less than 400 mg means that you could take both pills at the same time with a meal and still ensure they are absorbed well. These pills also include vitamin D3, which works in partnership with calcium to maintain strong bones. Keep in mind that if you have increased calcium needs, you would need to take an additional pill at a separate time of day. One bottle contains 50 servings, so it will easily last you more than one month.
Citracal Petites have been tested and approved by ConsumerLab, one of the three most reputable organizations that check supplements for contents and contaminants.
Serving Size: 2 caplets | Vitamin D3: 500 IU | Calcium: 400 mg | Sodium: 5 mg
Exceeds 500 mg calcium per serving
Calcium carbonate is the most commonly found form of calcium and is often available to consumers at a comfortable price point. This bottle contains 220 tablets, and the cost comes out to just a few cents per dose. Calcium carbonate contains the highest concentration of calcium at 40% by weight, and this supplement pairs calcium carbonate with vitamin D3 in one convenient tablet. This supplement contains no added colors or artificial flavors and is gluten-free.
It is important to note that one serving of this supplement contains 600 mg of calcium, which, when taken at one time, may not be optimally absorbed. It also may cause more of the classic digestive upset that is also common with calcium carbonate supplements.
Of note, NatureMade's calcium carbonate has been tested and approved by USP, one of the top third party certifiers.
Serving Size: 1 tablet | Vitamin D3: 400 IU | Calcium: 600 mg
contains vitamin D3, vitamin K, and magnesium
Bone is more complex than it might appear, and, while calcium is the foundation, there are other critical nutrients that our bodies need to build strong bones. TheraCal Bone Health Supplement contains calcium citrate in combination with vitamin D3, vitamin K2, and magnesium.
Vitamin K is the key nutrient that helps bind calcium and create a mature bone cell. It also plays an important role in preventing calcium deposits in blood vessels. In postmenopausal women, low magnesium intake has been correlated with rapid bone loss and weaker bones, and some trials have shown benefits from supplementation. This supplement is then the trifecta, including not only vitamin D but also vitamin K and magnesium.
TheraCal is produced without artificial dyes, is certified gluten-free, and tested in a high quality lab. It has been certified by one of our top three third party organizations—NSF. The manufacturer of this supplement, Theralogix, also offers it in varying doses of vitamin D so you can pick the one that meets your needs. One of the downsides is cost; a 90-day supply usually costs at least $50.
Serving Size: 2 tablets | Vitamin D3: 1000 IU | Calcium: 500 mg | Magnesium: 500 mg | Strontium: 50 mg | Boron: 1.5 mg | Vitamin K: 50 mcg
contains vitamin D3 and vitamin K2
Garden of Life is a brand synonymous with top quality, organic products and made in a certified USDA Organic manufacturing facility. They keep their products free of gluten, synthetic binders and fillers, and GMOs, and prioritize safety above all. If you follow a vegan diet, or simply value a plant-based supplement, then the mykind Organics Plant Calcium is for you. The supplement contains 800 mg of calcium sourced from organic algae, which the company mentions makes it easy to digest. In addition to calcium, you will find vitamin D3, plant-sourced magnesium, and natto-derived vitamin K2.
This organic supplement doesn’t stop there though. It also contains a blend of over 20 organic fruit and vegetable powders—from apple and beet, to cauliflower and kale—to provide more micronutrient benefits. Due to this added benefit, the number of tablets is increased to three total, which may be difficult for people to remember taking all of them daily.
While certified gluten-free, this supplement is the only one of our picks that is not verified by a third party organization to ensure it contains what it says it contains in the quantities listed on the label.
Serving Size: 3 tablets | Vitamin D: 1000 IU | Calcium: 800 mg | Magnesium: 60 mg | Vitamin K2: 80 mcg | Magnesium: 60 mg
Free of: artificial colors & flavors, lactose, and gluten
contains vitamin D and phosphorus
Who wouldn’t want to take their supplements when they are chewable and taste great? Costco’s Signature brand, Kirkland, has delivered a product that is easy to consume, comes in two tasty flavors (orange and cherry), and is USP verified.
Each serving of 2 gummies contains 500 mg tribasic calcium phosphate, 1000 IU vitamin D, and 230 mg of phosphorus, which work in harmony for bone strengthening. If you are conscious of added sugars, it’s important to call out that it does contain 3 grams of sugar per serving; however, this is modest compared to most chewable supplements.
Keep in mind that this form of calcium may not be ideal for certain populations and may have some side effects, such as digestive issues, increased thirst, increased urination, and decreased appetite.
Serving Size: 2 gummies | Calories: 20 | Total Carbohydrate: 5 g | Total Sugars: 3 grams | Vitamin D: 25 mcg (1,000 IU) | Calcium: 500 mg | Phosphorus: 230 mg
Bayer Citracal Petite is our top calcium pick. It is a high quality supplement from a trusted brand that contains 400 mg calcium citrate and vitamin D to support bone strength without digestive upset. The small size makes it a convenient pill for many populations to tolerate.
Our team works hard to be transparent about why we recommend certain supplements; you can read more about our dietary supplement methodology here.
We support supplements that are evidence-based and rooted in science. We value certain product attributes that we find to be associated with the highest quality products. We prioritize products that are third-party tested and certified by one of three independent, third party certifiers: USP, NSF, or ConsumerLab.
It's important to note that the FDA does not review dietary supplements for safety and effectiveness before they go to market. Our team of experts has created a detailed, science-backed methodology to choose the supplements we recommend.
Although we know that calcium plays a vital role in the body and that consuming enough calcium from foods is very important, the research on calcium supplements is less clear. Many supplement companies still make claims about how their product might benefit you, and these promises are not necessarily backed by quality research. Let’s look into a few areas where calcium supplementation may or may not be beneficial.
Osteoporosis is a skeletal disorder that causes weaker bones and is usually associated with aging. People with osteoporosis have a higher risk of fracture. Women are at greater risk of this than men because they naturally have smaller bones and, after menopause, estrogen (which helps protect bones) decreases significantly. In theory, supplementing with calcium and vitamin D could reduce this risk, but research does not necessarily support this.
Some research has shown that higher dietary calcium intake is linked to greater bone mineral density in women over 60; other research has shown no effect. The evidence on calcium supplementation and fractures is also inconclusive. A meta analysis (research that looks at many different studies) showed no effect of calcium and vitamin D supplementation on hip fracture risk.
Calcium has also been studied to see if it may help prevent cancer. Most high quality research has shown no effect from calcium and vitamin D supplementation on cancer risk, though one study showed that higher total calcium intake may decrease the risk of colorectal cancer.
In the blood, calcium helps to decrease the amount of fat your body absorbs, and therefore people have wondered if it may reduce the risk of cardiovascular disease (CVD). It looks like this might be the case for eating more calcium in the diet but not with calcium supplements.
A large study in Australia found that adults with the highest calcium intake from their diets, excluding supplements, had a 25% lower risk of stroke. On the other hand, there is evidence that calcium supplements may increase CVD. In one large-scale study of women, calcium supplements (with or without vitamin D) were associated with a modestly higher risk of cardiovascular events, especially heart attacks.
The leading cause of illness and death related to pregnancy and childbirth for both mother and baby in the United States is preeclampsia. This condition is a combination of high blood pressure and protein in the urine that occurs sometime after 20 weeks of pregnancy.
According to the American College of Obstetrics and Gynecology, supplementing daily with 1,500–2,000 mg calcium might reduce the severity of preeclampsia in pregnant people, but only for those who consume less than 600 mg/day of calcium.
The research on calcium supplements and weight loss is also mixed. So we turn to the highest quality research to draw conclusions from, a research analysis, which looks at the results of many studies. In a research analysis that looked at 41 studies, no association was found between increased dairy food intake or supplemental calcium intake on weight loss.
Supplements that are third-party tested are sent to a lab where they are tested to ensure they contain what they say they contain and are not contaminated with specific high-risk, common contaminants. However, it’s important to note:
When choosing a supplement, it’s important to obtain it from a trusted source that upholds standards of efficacy and purity, and calcium is no exception. One of the biggest concerns with calcium supplements is related to the quantity of the mineral actually contained in the pill or powder. A product label may say it contains a certain amount of calcium, but in fact it falls short. Another concern is that many sources of calcium also contain heavy metals such as lead, arsenic, and cadmium. Choosing your supplement from a trusted source is imperative, especially for women who are pregnant.
Calcium is available in various forms. Some are more effective and desirable than others. The most commonly available forms are: calcium carbonate, calcium malate, calcium citrate, tricalcium phosphate, calcium lactate, and calcium gluconate. Let's look in more depth at the four of these forms used in our top supplement picks.
Calcium carbonate is the most common and also the least expensive form. However, it can cause gastrointestinal upset, such as bloating, gas, and constipation.
Calcium malate and calcium citrate are the forms that are more effective at raising calcium levels compared to carbonate, but it’s important to consume these two forms with a meal as they do require stomach acid (which our bodies produce when we eat) to be best absorbed.
Tricalcium phosphate is not only used as a supplement but also as an additive to powdered food items to prevent caking and in processed foods to enrich or fortify them with calcium. Possible side effects include nausea, vomiting, constipation, increased thirst, increased urination, and decreased appetite. It can also interact with certain medications and may not be ideal for people with certain health conditions.
As a final consideration, all of these forms of calcium, with the exception of carbonate, usually come in the form of large pills or multiple tablets and can be more expensive.
It is essential to carefully read the ingredient list and nutrition facts panel of a supplement to know which ingredients and how much of each ingredient is included, relative to the recommended daily value of that ingredient. Please bring the supplement label to a healthcare provider to review the different ingredients contained in the supplement and any potential interactions between these ingredients and other supplements and medications you are taking.
Calcium relies on vitamin D for absorption, and so it’s not uncommon to see calcium supplements containing vitamin D as well. Vitamin K and magnesium, which also helps promote calcium deposition in bone, might also be found in the same supplement.
According to current recommendations from the Dietary Guidelines for Americans, the Recommended Dietary Allowances (RDAs) for calcium are as follows:
Excessive calcium supplementation can cause dangerous health problems; therefore, Tolerable Upper Intake Levels (ULs) have been established. No matter whether you get your calcium from food or supplements, you should not exceed:
2500 mg per day for those aged 1-8 years and 19-50 years old
3000 mg per day for those aged 9-18 years
2000 mg per day for those aged 51 and older
It is important not to exceed these limits because, although rare, hypercalcemia (high serum calcium) or hypercalciuria (high urine calcium) can lead to poor muscle tone, kidney issues, constipation, nausea, weight loss, fatigue, heart arrhythmias, and a higher risk of death from heart disease.
Although it depends on the form, most calcium supplements should be taken with a meal but separately from most other supplements. It is generally advised to not take more than 500 mg at one time as the body may not be able to absorb more than this at once. Calcium should also be taken separately—at least 2 hours apart—from an iron supplement, as these two minerals compete for absorption.
According to Rosen, you should avoid taking a calcium supplement with meals that include whole grains, seeds, legumes, nuts, spinach, soy, potatoes, or beets. They can interfere with the way your body naturally absorbs calcium. This doesn’t mean you should refrain from eating these nutrient-dense foods (far from it!). Rosen recommends continuing to eat these foods but taking your calcium supplement at a different time.
Constipation is a dreaded side effect of many medications and supplements, yet the link between calcium and constipation remains unclear. According to the Institute of Medicine, calcium carbonate can cause constipation, flatulence, and bloating, and so it could be wise to choose a different form, or take smaller doses at one time and consume it with food. On the other hand, a small randomized control trial from 2016 showed no effect of 500 mg of either calcium carbonate or phosphate on constipation.
Depending on the form and preparation, research shows that calcium is absorbed 2-4 hours after consumption, and calcium carbonate powder is absorbed about 40 minutes more rapidly than calcium citrate tablets .
Calcium from foods does not contribute to kidney stones and can actually help prevent them. However, calcium in the form of a supplement may increase your chances of forming new calcium oxalate kidney stones. Recent research has shown that supplemental calcium may increase the risk for kidney stone formation in postmenopausal women supplementing with 1,000 mg of calcium per day. Although the risk was small, you may want to take it into consideration if you choose to take a calcium supplement.
As we age, stomach acid production often declines, so calcium carbonate may be more effective for seniors (since the other common calcium supplements require stomach acid for absorption). A supplement that contains calcium and vitamin D is best for preserving bone health in older people. Try Nature Made's Calcium with Vitamin D. Also, take into consideration the size of pill and ease of swallowing.
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