Can I take magnesium and vitamin D together?
Yes. No source we checked says to separate them. The NIH notes that magnesium affects levels of the active form of vitamin D [1], and a review reports that the enzymes that process vitamin D in the liver and kidneys seem to need magnesium as a cofactor [3]. No official source gives a set time of day for the pair.
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What the sources say about magnesium and vitamin D
Magnesium affects the concentrations of both parathyroid hormone and the active form of vitamin D, which the NIH describes as major regulators of bone homeostasis [1]. A 2018 review states that magnesium assists in the activation of vitamin D and that all of the enzymes that metabolize vitamin D seem to require magnesium as a cofactor in reactions in the liver and kidneys [3]. Vitamin D itself promotes calcium absorption in the gut [2]. The NIH also lists vitamin D deficiency among the factors that can lower magnesium status in people with alcohol dependence [1].
How to time them
No official source gives a spacing rule or a best time of day for taking magnesium and vitamin D together. Vitamin D is fat-soluble, and fat in the gut at the same time improves its absorption, although some is absorbed without dietary fat [2]. For magnesium, forms that dissolve well in liquid are absorbed more completely, and the aspartate, citrate, lactate and chloride forms tend to be more bioavailable than oxide and sulfate [1]. The NIH upper limits for adults are 350 mg a day of supplemental magnesium [1] and 100 mcg (4,000 IU) a day of vitamin D [2].
Who should ask a doctor or pharmacist first
Ask your pharmacist or doctor first if you take medicines. Magnesium can lower the absorption of oral bisphosphonates and binds tetracycline and quinolone antibiotics, and diuretics and proton pump inhibitors can change magnesium status [1]. Vitamin D may interact with orlistat, statins, steroids and thiazide diuretics; thiazides plus vitamin D might lead to high blood calcium, especially in older adults and people with reduced kidney function [2]. People with impaired kidney function have a higher risk of magnesium toxicity [1].
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
No source we checked says to separate them, and no official source gives a timing rule for the pair. Vitamin D is absorbed better when there is fat in the gut [2].
Sources
- Magnesium: Fact Sheet for Health Professionals — NIH Office of Dietary Supplements
- Vitamin D: Fact Sheet for Health Professionals — NIH Office of Dietary Supplements
- Role of Magnesium in Vitamin D Activation and Function (Uwitonze AM, Razzaque MS. J Am Osteopath Assoc. 2018;118(3):181-189) — PubMed, National Library of Medicine
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 .