Can I take vitamin D and calcium together?
Yes, they are often combined. NIH says vitamin D is required for the gut to absorb calcium by active transport, and many supplements contain calcium plus vitamin D [2]. No official source says to take them apart. NIH also notes that taking calcium supplements in combination with vitamin D supplements may increase the risk of certain adverse effects [1].
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What the sources say about vitamin D and calcium
NIH says vitamin D promotes calcium absorption in the gut and maintains the blood calcium and phosphate levels needed for normal bone mineralization [1]. Vitamin D is required for calcium to be absorbed in the gut by active transport [2]. Many supplements contain calcium plus vitamin D, commonly with 500 or 600 mg of calcium [2]. The NHS says vitamin D helps regulate the amount of calcium and phosphate in the body [3]. Because vitamin D increases calcium absorption, NIH says vitamin D toxicity causes high blood calcium [1]. In one large trial, women with high calcium intakes (about 2,100 mg a day from food and supplements) and moderate vitamin D intakes had a 17% higher risk of kidney stones over 7 years, though shorter trials did not find more kidney stones [1].
How to time them
No official source says to separate vitamin D and calcium or gives a set timing for them. NIH says calcium supplements are generally absorbed better with food, calcium citrate can be taken without food, and absorption is highest at doses of 500 mg or less [2]. NIH notes that fat in the gut helps vitamin D absorption, but some is absorbed even without fat [1]. In the UK, the NHS says everyone should consider a daily 10 mcg vitamin D supplement in autumn and winter [3], and that adults need 700 mg of calcium a day, which they should be able to get from their diet [4].
Who should ask a doctor or pharmacist first
Ask a doctor first if you take a thiazide diuretic: with vitamin D supplements it might lead to high blood calcium, especially in older adults and people with reduced kidney function or hyperparathyroidism [1]. NIH also lists orlistat, statins and steroids for vitamin D [1], and dolutegravir, levothyroxine, lithium and quinolone antibiotics for calcium [2]. Ask too if you have a condition that limits fat absorption, such as celiac disease, Crohn's disease or cystic fibrosis [1]. NIH says higher supplemental calcium intakes might increase the risk of kidney stones [2].
Supin schedules what you take around each other
Supin puts what you take into a daily routine by time of day, follows each product's label, and reminds you.
Questions people ask next
NIH says vitamin D is required for calcium to be absorbed in the gut by active transport [2].
No official source names a best time of day for either.
NIH says absorption from supplements is highest with doses of 500 mg or less; for example, the body absorbs about 36% of a 300 mg dose and 28% of a 1,000 mg dose [2].
Sources
- Vitamin D: Fact Sheet for Health Professionals — NIH Office of Dietary Supplements
- Calcium: Fact Sheet for Health Professionals — NIH Office of Dietary Supplements
- Vitamin D - Vitamins and minerals — NHS
- Calcium - Vitamins and minerals — NHS
Educational information, not medical advice, and not a recommendation for you. Check with your doctor or pharmacist before starting, combining or changing supplements, especially if you take medication, are pregnant or have a health condition. Supin sells a subscription, not supplements. Last reviewed .