This review from 2007 is the only comprehensive assessment of the various types of calcium salt forms. Suggesting that calcium carbonate offers an effective and cost-efficient form that should be taken with a meal to ensure optimal absorption.
References:
Straub DA. Calcium supplementation in clinical practice: a review of forms, doses, and indications. Nutr Clin Pract. 2007 Jun;22(3):286-96. doi: 10.1177/0115426507022003286. PMID: 17507729.
