Calcium supplements: How to take them

The best time to take calcium supplements depends on the type of calcium the supplements contain.

Calcium supplements typically contain calcium carbonate or calcium citrate. Check the label to see which form the supplement contains. Calcium carbonate should be taken with meals. This is because acid secreted by your stomach enhances absorption of calcium carbonate. Calcium citrate does not need to be taken with meals. It does not matter what time of day you take either form of calcium.

Calcium is absorbed most efficiently by the body when it is taken in amounts of 500 milligrams (mg) or less. If you take 1,000 mg of calcium a day, split it in two or more doses over the course of the day.

Calcium supplements can impair absorption of some medications, such as iron supplements and certain antibiotics and blood pressure drugs. For this reason, you shouldn't take calcium at the same time as these medications. Consult your doctor or pharmacist regarding any possible interactions between calcium and other medications you take.