Roughly 60% of your body's magnesium is stored in your bones. It's not a trace mineral — it's a structural component. Yet many Canadians aren't getting enough, and the shortfall affects more than just muscle cramps.
Calcium and vitamin D are the well-known duo for bone health, but magnesium deserves a seat at the table. This mineral plays dozens of roles in bone metabolism — it influences how bone-forming cells (osteoblasts) and bone-resorbing cells (osteoclasts) function, it's required to convert vitamin D into its active hormonal form, and it directly affects calcium absorption and regulation. Deficiency doesn't just cause muscle spasms; over time it contributes to bone loss.
The frustrating part is that magnesium is underfunded in research and underdiscussed in clinical settings — partly because blood magnesium tests often look normal even when cellular stores are depleted. Most of your body's magnesium lives in bone and inside cells, not in blood serum, making standard testing misleading.
The mechanisms are multiple and interconnected. Magnesium is embedded in hydroxyapatite — the crystalline mineral matrix that gives bones their hardness. Adequate magnesium produces larger, better-formed crystals; deficiency results in more brittle, fragile crystals that are more prone to fracture.
Magnesium also influences parathyroid hormone (PTH) regulation. PTH controls how much calcium is released from bone and how much the kidneys excrete or retain. When magnesium is low, PTH function becomes blunted and erratic, which can lead to abnormal calcium metabolism even when calcium intake is adequate. In other words, taking extra calcium without enough magnesium doesn't work as well as it should.
The vitamin D connection is equally direct: the enzyme that converts vitamin D into its active form (calcitriol) is magnesium-dependent. Low magnesium can make vitamin D supplementation less effective — your D levels may look fine on paper while the biological activity remains limited.
Early deficiency is often silent. As it becomes more significant, common symptoms include:
Many of these symptoms are non-specific and could have other causes. But if you experience several of them, particularly alongside a diet low in magnesium-rich foods, it's worth discussing with your doctor. A serum magnesium test can catch frank deficiency, though it misses subclinical insufficiency.
Health Canada's Recommended Dietary Allowance for magnesium is 320 mg/day for women over 31 and 420 mg/day for men over 31. The good news is that many common Canadian foods are solid sources:
| Food | Serving | Magnesium (approx.) |
|---|---|---|
| Pumpkin seeds (pepitas) | 30g (¼ cup) | 156 mg |
| Hemp seeds | 30g (3 tbsp) | 100 mg |
| Almonds | 30g | 80 mg |
| Black beans (cooked) | 125 ml (½ cup) | 60 mg |
| Edamame (cooked) | 125 ml (½ cup) | 50 mg |
| Brown rice (cooked) | 125 ml (½ cup) | 42 mg |
| Spinach (cooked) | 125 ml (½ cup) | 78 mg |
| Banana | 1 medium | 32 mg |
| Dark chocolate (70–85%) | 30g | 64 mg |
| Atlantic salmon (cooked) | 85g | 26 mg |
A well-constructed whole food diet — with seeds, nuts, legumes, and whole grains — can get most people close to or at the RDA. The challenge is that highly processed diets fall well short, and magnesium is lost when grains are refined and when vegetables are boiled rather than steamed or eaten raw.
This is where confusion sets in. Walk into any Shoppers Drug Mart or health food store and you'll find at least four or five different forms of magnesium. They're not all equivalent.
Magnesium bound to glycine, an amino acid. This is the form most often recommended for people focused on sleep, anxiety, or general supplementation. It's well-absorbed, gentle on the digestive system, and unlikely to cause loose stools even at higher doses. If you're taking magnesium primarily for bone health and want to avoid GI side effects, glycinate is a strong choice. It's also calming — many people find it helps with sleep, which is a bonus.
Magnesium bound to citric acid. Good bioavailability, widely available, and less expensive than glycinate. The downside is a mild laxative effect at higher doses — which can actually be useful for people with constipation, but unpleasant for everyone else. Magnesium citrate in powder form (like Natural Calm) is popular in Canada and easy to dissolve in warm water. Start with a low dose if you haven't used it before.
The most common form in cheap, generic supplements. Contains a high percentage of elemental magnesium by weight — but it's poorly absorbed, with studies showing only around 4% bioavailability compared to around 30% for citrate and higher for glycinate. Magnesium oxide is best suited as a laxative (it works well for that) or for acute antacid use, not for raising tissue magnesium levels. Avoid it if your goal is bone health or any systemic benefit.
Bound to malic acid, found naturally in fruits. Good absorption and often recommended for people with chronic fatigue or muscle pain. Less commonly found in Canadian pharmacies but available at health food stores and online.
A newer form developed at MIT, claimed to cross the blood-brain barrier more effectively. Mostly studied for cognitive function. More expensive and not specifically indicated for bone health — not worth the premium for this particular purpose.
Available throughout Canada at health food stores, Costco, and online. Natural Calm is magnesium citrate in a powdered form you mix into water. It's been popular in Canada for over a decade, comes in several flavours, and is a reasonable option if you prefer a drink format. Dose carefully — too much at once will cause loose stools.
Jamieson's glycinate formulation is available at most major Canadian pharmacies and grocery stores. Good quality, NPN-licensed, and reasonably priced. A solid everyday option.
BC-based brand with good quality control. Available in capsule form at health food stores across Canada. Their magnesium bisglycinate product is also worth noting for those who want the glycinate form.
Broad availability at Costco and pharmacies nationwide. Affordable and reliable. Check the form on the label — they make several versions.
Canadian brand sold at health food stores including Popeye's Supplements and many independent retailers. Their magnesium complex uses multiple forms for a broader absorption profile.
Compare magnesium glycinate, citrate, and malate from Canadian and international brands with shipping to all provinces.
Browse Magnesium Supplements →Most adults supplementing for bone health purposes aim for 200–350 mg of elemental magnesium per day from supplements, accounting for what they get from food. The tolerable upper intake level from supplements (not food) is set at 350 mg/day by Health Canada — above this, GI symptoms become more likely though toxicity from food sources is not a concern.
Timing doesn't significantly affect absorption, but many people prefer to take magnesium in the evening because of its mildly relaxing effect. If you take calcium supplements, taking magnesium at a different time of day may slightly reduce competition for absorption, though this concern is often overstated.
For most healthy adults, magnesium supplementation at appropriate doses is safe, well-tolerated, and genuinely useful for bone health — especially when combined with adequate calcium, vitamin D, and vitamin K2.