Calcium Carbonate or Calcium Citrate?
Calcium carbonate is the more common of the two main types of calcium supplements. You should also eat something when you take it to help your body use it best. It doesn't matter if you take calcium citrate with or without food.
A supplement may have more calcium carbonate as an ingredient than one with calcium citrate, but they could be equally effective. When you compare products, check the labels to find out how much actual calcium you'll be getting in a dose.