Vitamin D, Immunity, and the Missing Link: Magnesium
The connection between vitamin D3 and immune health has gained major attention in recent years, especially during and after the COVID-19 pandemic. While early research suggested that maintaining healthy vitamin D levels could help reduce the severity of viral infections like COVID-19, it also highlighted a critical factor often overlooked: vitamin D3 needs magnesium to be effective.
Don’t Mega-Dose Without a Strategy
Taking a vitamin D supplement—especially during Canada's long cold and flu season—is a smart move. But loading up on high doses without understanding how it works in the body can backfire. Experts now emphasize that vitamin D must be activated to work, and that activation depends on magnesium.
Why Magnesium Matters
Without enough magnesium, vitamin D3 stays stored in the body in an inactive form, offering little to no immune support. Studies show that people who supplement with magnesium are not only less likely to be vitamin D deficient, but they also need less vitamin D supplementation overall to reach optimal levels.
Dr. Mohammed Razzaque, co-author of a study published in The Journal of the American Osteopathic Association, explains:
“People are taking vitamin D supplements but don't realize how it gets metabolized. Without magnesium, vitamin D is not really useful or safe.”
Don’t Forget Vitamin K2
Another essential player in vitamin D3 supplementation is vitamin K2. High doses of vitamin D can increase calcium absorption, but without K2, that calcium can deposit in the wrong places—like arteries and joints. K2 activates proteins that direct calcium to the bones and teeth, supporting both bone health and cardiovascular health.
Sunshine Helps—But Isn’t Always Enough
Both sunlight and supplements follow similar metabolic pathways that require magnesium and K2 for proper use. If you live in Canada, you know our sunlight isn’t strong enough year-round to rely on it as your sole vitamin D source. However, short daily sun exposure without sunscreen can still help your skin produce and retain vitamin D naturally. (Just be sure to apply sunscreen or seek shade after a few minutes to protect your skin.)
Simplify Your Supplement Routine
To support your immune system, especially during flu season, make sure you’re not just taking vitamin D3 alone. The general guideline is to get at least 100 mg of magnesium per 1,000 IU of vitamin D3.
Or simplify with Vitamin D Plus—a thoughtfully formulated supplement combining:
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Vitamin D3
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Magnesium bisglycinate (highly absorbable)
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Vitamin K2 (MK-7)
This trio helps to ensure your vitamin D is properly activated and utilized.
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