What form of calcium supplementation do you like the best? Both calcium citrate / malate and calcium microcrystalline hydroxyapatite seem good. Do you prefer one over the other? Do you know of any side effects or drug interactions with either of these?

Thank you for your advice. 

Laura 

Both citrate malate and hydroxyapatite are good forms. For Osteoporosis and fractures I use them together. As for drug interactions, the most common ones are: 

• Calcium - may reduce the effectiveness of Ca+ channel blockers.
  
• Glucocorticoids - may lower serum Ca+ Oral Contraceptives - may improve absorption of Ca+.
  
• Tetracycline - use when long term may deplete Ca+.
  
• Calcium decreases bioavailability of ciprofloxacin.
  
• Digoxin increases renal Ca+ clearance.
  
• Neomycin impairs Ca+ absorption.
  
• Phenobarbital (long term) reduces Ca+ absorption.
  
• There are other drugs that can effect Ca+, as well. Check.