A complete safety, timing, and dosage guide for combining Magnesium (Citrate, Glycinate, Oxide, Threonate) with Vitamin C (Ascorbic Acid) — including how the two supplements interact, the best time of day to take each, and which populations should be careful.
Yes, vitamin C and magnesium are safe to take together, with no known negative interaction. You can combine vitamin C (ascorbic acid) and magnesium in any of its common forms.
Vitamin C and magnesium are neutral together — no significant interaction, so combining them is safe. Taking vitamin C and magnesium together can even be beneficial, as magnesium helps balance vitamin C's oxalate effects.
Vitamin C (ascorbic acid) is a water-soluble nutrient absorbed primarily in the ileum by sodium-dependent vitamin C transporters (SVCT1 and SVCT2), while magnesium is an essential mineral absorbed through a combination of passive paracellular diffusion and active transcellular transport involving transient receptor potential melastatin 6 (TRPM6) and TRPM7 channels. Because these two nutrients rely on distinct absorption mechanisms and do not compete for the same transport proteins, taking them simultaneously does not reduce the bioavailability of either. In the lumen of the intestine, vitamin C can increase the solubility of calcium oxalate, which in susceptible individuals may raise urinary oxalate excretion; magnesium, on the other hand, binds oxalate in the gut and forms magnesium oxalate, a soluble complex that is readily excreted, thereby reducing the amount of oxalate available for absorption. This complementary action means that magnesium may actually mitigate one of the theoretical downsides of high-dose vitamin C supplementation. Both nutrients also function as cofactors in enzymatic pathways — vitamin C in collagen synthesis and antioxidant recycling, magnesium in ATP production and hundreds of kinase reactions — but these roles are independent and do not create antagonism. There is no evidence that one depletes the other at standard supplemental doses.
If you need both supplements, take them together in the morning or evening with a meal — there is no need to space them apart. For optimal absorption, split vitamin C into 500 mg doses taken two to three times a day, and take magnesium once daily with your largest meal. If you find magnesium makes you drowsy, take it in the evening; if vitamin C energizes you, take it earlier in the day. If you miss a dose, simply take it with your next meal — do not double up. Choose magnesium glycinate or citrate for routine supplementation and consider a buffered vitamin C product if stomach sensitivity is an issue.
The form of magnesium significantly affects tolerability and absorption. Magnesium citrate is water-soluble and reasonably well absorbed but can have a laxative effect at higher doses, making it useful for constipation but potentially problematic if diarrhea is a concern. Magnesium glycinate is chelated and typically very gentle on the stomach, with high bioavailability, making it a good first choice for long-term supplementation. Magnesium oxide is inexpensive but poorly absorbed (roughly 4–5% bioavailability) and commonly causes loose stools, so it is usually best avoided if the goal is raising tissue magnesium levels. Magnesium threonate is a newer form that appears to cross the blood-brain barrier more effectively, though clinical evidence for superiority is still limited. Vitamin C is usually sold as ascorbic acid, which is effective but can cause GI discomfort in doses above 1,000 mg; buffered ascorbate forms such as sodium ascorbate or magnesium ascorbate can be gentler and may reduce stomach irritation.
This pair is commonly found in electrolyte and hydration powders, sleep support formulas, and immune health blends that also include zinc and vitamin D. It also appears in some multivitamin-mineral products where magnesium oxide is used as a cost-effective filler.
Yes, I can take vitamin C and magnesium together because they do not interfere with each other's absorption. I usually take them with a meal to reduce any stomach irritation. There is no need to separate them by hours.
Yes, it is safe to take vitamin C and magnesium daily. I just need to stay within recommended doses: up to 2,000 mg of vitamin C and 350 mg of supplemental magnesium for adults. I can split the doses if needed.
I do not need to wait any time between vitamin C and magnesium. I can take them together in one sitting, ideally with food. If I prefer, I can take one in the morning and one at night, but it is not necessary.
No, vitamin C and magnesium do not compete for absorption. They use different transport systems in the intestine. Actually, magnesium may help offset some of the oxalate effects of high-dose vitamin C, so the combination is complementary.
Most people can take vitamin C and magnesium together without issues, but I would be cautious if I have advanced kidney disease or a history of kidney stones. I would also avoid exceeding the upper limits if I am on other magnesium-containing medications.
I prefer to take them with food to avoid stomach upset, especially with high-dose vitamin C. Magnesium, particularly citrate or glycinate, can also be taken with food to improve tolerance, but an empty stomach is fine for most people at standard doses.
Reviewed by Caroline M. on April 11, 2026 for accuracy against the sources listed above. This page is educational and is not a substitute for professional medical advice.
The matrix has 86 supplements and 7310 pairwise interactions. Click any cell to see the full breakdown.