Calcium supplements are typically prescribed for the prevention and treatment of osteoporosis, osteomalacia, or rickets. They may also be recommended for people who do not consume enough calcium in their diet.

Calcium supplements may also be recommended for conditions affecting calcium absorption in the body, such as prolonged use of corticosteroids, inflammatory bowel disease, and celiac disease.

While getting the recommended amount of calcium is important, taking too much can cause problems like kidney stones, constipation, and stomachache. For this reason, calcium supplements should only be taken as directed by a doctor or other licensed healthcare professional.

Indications for use

Calcium supplements are generally recommended for the treatment of certain health problems and in cases of low calcium intake or conditions affecting calcium absorption in the body. Indications for supplementation include:

Osteoporosis;
Osteomalacia;
Rickets;
Use of corticosteroids like prednisone, prednisolone, or hydrocortisone;
Hypocalcemia;
Inflammatory bowel disease;
Bariatric surgery;
Celiac disease;
Low intake of calcium-rich foods.

Calcium supplements are also indicated for the treatment of hypoparathyroidism, a condition caused by decreased levels of parathyroid hormone in the blood. Symptoms can include weakness and bone abnormalities.

It is important to remember that vitamin D is essential for increased absorption of calcium in the body. Therefore it is also important to get the recommended amount of vitamin D through sunlight and by eating foods high in vitamin D, such as egg yolks, milk, and milk products.

Types of calcium supplements

Calcium supplements come in the form of capsules, pills, and injections and are available as calcium citrate, calcium carbonate, calcium phospate, and calcium gluconate. Calcium supplements may contain only calcium or be combined with vitamin D.

Dosing instructions

The type, dose, and duration of use will depend on the condition being treated and should be determined by your doctor, registered dietitian, or other licensed healthcare professional.

1. Calcium carbonate

Calcium carbonate is indicated for the treatment and prevention of osteoporosis and hypocalcemia. The recommended dose is between 100 and 500 mg per day. Because calcium carbonate requires stomach acid to be absorbed, it should be taken with meals and a full glass of water.

2. Calcium citrate

Calcium citrate is easier to absorb and is therefore usually prescribed to people with alterations in stomach acid production, such as the elderly and people who have undergone bariatric surgery, for example.

Calcium citrate pills should be taken on an empty stomach with a full glass of water. Dosing will depend on the condition being treated. Some examples include:

Calcium deficiency in adults and children over 6 years of age: 800 mg per day;
Calcium deficiency in people who are pregnant or breastfeeding: 1000 to 1200 mg per day;
Treatment of hypocalcemia: 800 to 1200 mg per day;
Prevention and treatment of osteoporosis: 800 to 1500 mg per day.

Calcium citrate may also be available in packets (as granules) or sold as a powder.

3. Calcium phosphate

Calcium phosphate is usually combined with vitamin D and can be found in the form of 600 to 1600 mg pills.

This supplement is typically indicated for the prevention of rickets as well as the prevention and treatment of osteoporosis. The recommended dose is 1 to 2 tablets per day, which should be taken with meals and a full glass of water.

4. Calcium gluconate

Calcium gluconate comes in injectable form and is indicated to treat low levels of calcium in the blood as well as hyperkalemia, which is an increase in the levels of potassium in the blood.

Calcium gluconate should only be administered at the hospital and is given through an IV by a nurse or other licensed healthcare professional.

5. Calcium caseinate

Calcium caseinate is a salt derived from casein, a milk protein. It is low in calcium and is therefore not indicated for the treatment of osteoporosis or calcium deficiency.

However, calcium caseinate may be used as an ingredient in supplements used by athletes to help build muscle mass and improve endurance.

Side effects

Calcium supplements may cause side effects like stomachache, vomiting, burping, constipation, dry mouth, increased urine volume, loss of appetite, and a metallic taste in the mouth.

Calcium supplements can also make it difficult for the body to absorb zinc and iron, increasing the risk for kidney stones and hypercalcemia, which is an increased amount of calcium in the blood.

Taking more than 2000 mg of calcium supplements per day can increase the risk of calcification of the blood vessels, leading to cardiovascular disease including heart attack and high blood pressure.

Contraindications to use

Calcium supplements are not indicated for people with advanced chronic kidney disease, severe hypercalciuria, hypercalcemia, hypervitaminosis D (vitamin D toxicity), or sarcoidosis, a condition characterized by the formation of inflammatory cells in the body leading to symptoms like excessive tiredness as well as joint pain or swelling.

Children and people who are pregnant should only take calcium supplements if advised by a doctor.

It is important to tell your doctor or other healthcare provider about all medications and supplements you are taking before starting calcium supplements. This is because calcium supplements can interfere with the effects of other medications.