Can You Take Calcium and Vitamin C Together?

Dose or timing may matter

The short answer

High-dose vitamin C is metabolized to oxalate, which combines with urinary calcium to form calcium oxalate kidney stones. Co-supplementation may elevate stone risk beyond either alone.

How to arrange timing

Keep vitamin C below 1,000 mg/day when taking calcium supplements. Stay well-hydrated and consider monitoring urinary oxalate levels.

Reference

Reference noted for this combination: Massey LK et al. J Nutr. 2005;135(7):1673-1677; Thomas LD et al. JAMA Intern Med. 2013;173(5):386-388

Important context

Whether supplements suit you together also depends on dose, product formulation, health conditions, and medication use. Ask a doctor or pharmacist first if you take medication, are pregnant or breastfeeding, or have a chronic condition.