Calcium is the most abundant mineral in the human body. Average healthy males have about two and a half to three pounds of calcium while females have about two pounds. Approximately 99 percent of calcium is present in the bones and teeth, which leaves only about one percent in cells and body fluids. While the most important function of calcium involves the maintenance of skeletal health, the small percentage of calcium outside the bones is used to maintain a variety of vital body functions.

Milk and dairy products are the major source of dietary calcium for most people. Other good sources are dark green leafy vegetables, broccoli, legumes, nuts, and whole grains.

Dosage Info

Dosage Range

Dosages that have been used in clinical studies range from 500-2,500mg daily. (1) , (2)

Most Common Dosage

1,200mg daily.

1000mg elemental calcium
= ~3,950mg calcium acetate
= ~2,500mg calcium carbonate
= ~3,700mg calcium chloride
= ~4,740mg calcium citrate
= ~11,110mg calcium gluconate
= ~7,690mg calcium lactate
= ~4,000mg microcrystalline hydroxyapatite compound (MCHC)
= ~3,450mg calcium phosphate, dibasic anhydrous
= ~4,350mg calcium phosphate, dibasic dihydrate
= ~2,500mg calcium phosphate, tribasic

Dosage Forms

Tablets, capsules, powder, chewable tablets, functional foods, liposomal sprays, and injections (Rx only).

Interactions and Depletions



Reported Uses

As most people know, calcium is crucial for the development and long-term health of bones and teeth. The body’s need for calcium is greatest during periods of rapid growth including childhood, pregnancy, and lactation. (3) , (4)

Calcium is also necessary for a wide array of other functions. Calcium may initiate muscle contractions. For this reason it plays a vital role in maintaining a healthy heartbeat. It is also involved in the body’s blood clotting process. On the cellular level, calcium regulates the passage of nutrients and wastes through cell membranes. It is also involved in the regulation of various enzymes that control muscle contraction, fat digestion, and metabolism. Finally, calcium regulates the transmission of nerve impulses.

There are several targeted applications for calcium. For instance, it may be involved in blood pressure regulation. Studies have suggested that low levels of calcium are associated with high blood pressure. Studies also suggest that it may also aid in the prevention of colorectal cancer in men. (5) , (6) What’s more, calcium supplementation may reduce cholesterol levels. (7)

By reducing stone formation, calcium supplementation has shown promise in the treatment of kidney stones. (8) , (9) For support of PMS, calcium may dramatically reduce symptoms. (10) Calcium taken after the 20th week of pregnancy may also reduce a woman’s risk of pregnancy-related hypertension. (11)

Calcium has also received much attention for its role in supporting bone health in postmenopausal women. Research suggests that calcium can slow, but not completely stop, the progression of osteoporosis. (12) Calcium's importance for maintaining strong, healthy bones and slowing bone loss cannot be overstated. Studies have suggested that during perimenopause, calcium absorption decreases (13) and thus calcium supplements are a prudent dietary measure during menopause. Various types and dosage forms of calcium including calcium-fortified milk, high calcium milk powder, and chicken egg shell powder have been shown to delay bone loss in postmenopausal women. (14) , (15) , (16)

Toxicities & Precautions


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This dietary supplement is considered safe when used in accordance with proper dosing guidelines.

Health Conditions

If you have a history of kidney stones talk to your doctor before taking this dietary supplement. (17)

Pregnancy / Breast Feeding

To date, the medical literature has not reported any adverse effects related to fetal development during pregnancy or to infants who are breast-fed. Proper nutrition is essential during pregnancy for the healthy development of the fetus. Numerous vitamins and minerals are a vital part of proper nutrition. If you are pregnant, think you might be pregnant, trying to get pregnant, or breast-feeding an infant, talk to your healthcare professional about supplementing your diet with appropriate vitamins and minerals.

Age Limitations

To date, the medical literature has not reported any adverse effects specifically related to the use of this dietary supplement in children. Vitamins and minerals are an essential part of proper growth and development. Talk to your healthcare professional about the appropriate use of vitamins and minerals in children. Do not use any vitamin or mineral in children under 2 years of age unless first discussed with your healthcare professional.


  1. View Abstract: Heaney RP. Calcium supplements: practical considerations. Osteoporos Int. Feb1991;1(2):65-71.
  2. View Abstract: Dawson-Hughes B, Harris SS, Krall EA, Dallal GE. Effect of calcium and vitamin D supplementation on bone density in men and women 65 years of age or older. N Engl J Med. Sep1997;337(10):670-676.
  3. View Abstract: Abrams SA. Calcium turnover and nutrition through the life cycle. Proc Nutr Soc. May2001;60(2):283-9.
  4. View Abstract: O'Brien KO, Nathanson MS, Mancini J, Witter FR. Calcium absorption is significantly higher in adolescents during pregnancy than in the early postpartum period. Am J Clin Nutr. Dec2003;78(6):1188-93.
  5. View Abstract: Rozen P, et al. Calcium supplements interact significantly with long-term diet while suppressing rectal epithelial proliferation of adenoma patients. Cancer. Feb2001;91(4):833-40.
  6. View Abstract: Satia-Abouta J, Galanko JA, Martin CF, Potter JD, Ammerman A, Sandler RS. Associations of micronutrients with Colon Cancer risk in African Americans and whites: results from the North Carolina Colon Cancer Study. Cancer Epidemiol Biomarkers Prev. Aug2003;12(8):747-54.
  7. View Abstract: Bell L, et al. Cholesterol-lowering Effects of Calcium Carbonate in Patients with Mild to Moderate Hypercholesterolemia. Arch Intern Med. Dec1992;152(12):2441-44.
  8. Marshall RW, et al. Relationships Between Calcium and Oxalic Acid Intake in the Diet and Their Excretion in the Urine of Normal and Renal-stone-forming Subjects. Clin Sci. Jul1972;43(1):91-99.
  9. View Abstract: Curhan GC, Willett WC, Speizer FE, Spiegelman D, Stampfer MJ. Comparison of dietary calcium with supplemental calcium and other nutrients as factors affecting the risk for kidney stones in women. Ann Intern Med. Apr1997;126(7):497-504.
  10. View Abstract: Thys-Jacobs S, et al. Calcium Carbonate and the Premenstrual Syndrome: Effects on Premenstrual and Menstrual Symptoms. Premenstrual Syndrome Study Group. Am j Obstet Gynecol. Aug1998;179(2):444-52.
  11. View Abstract: Belizan JM, et al. Calcium Supplementation to Prevent Hypertensive Disorders of Pregnancy. N Engl J Med. Nov1991;325(20):1399-405.
  12. View Abstract: Dawson-Hughes B. Calcium Supplementation and Bone Loss: A Review of Controlled Clinical Trials. Am J Clin Nutr. Jul1991;54(1):274S-80S.
  13. View Abstract: Wishart JM, Clifton PM, Nordin BE. Effect of perimenopause on calcium absorption: a longitudinal study. Climacteric. Jun2000;3(2):102-8.
  14. View Abstract: Cleghorn DB, et al. An open, crossover trial of calcium-fortified milk in prevention of early postmenopausal bone loss. Med J Aust. Sep2001;175(5):242-5.
  15. View Abstract: Lau EM, Woo J, Lam V, Hong A. Milk supplementation of the diet of postmenopausal Chinese women on a low calcium intake retards bone loss. J Bone Miner Res. Sep2001;16(9):1704-9.
  16. View Abstract: Schaafsma A, Pakan I, van der Veer E. Positive effects of a chicken eggshell powder-enriched vitamin-mineral supplement on femoral neck bone mineral density in healthy late post-menopausal Dutch women. Br J Nutr. Mar2002;87(3):267-75.
  17. View Abstract: Domrongkitchaiporn S, et al. Risk of calcium oxalate nephrolithiasis after calcium or combined calcium and calcitriol supplementation in postmenopausal women. Osteoporos Int. 2000;11(6):486-92.