Magnesium
Supports hundreds of enzyme reactions, including muscle and nerve function.
Why it matters
Magnesium is involved in more than 300 enzyme reactions and supports muscle and nerve function, blood glucose control, blood pressure regulation, and bone structure.
- Supports muscle and nerve function.
- Helps regulate blood pressure and blood glucose.
- Participates in energy production and bone health.
If intake is too low
Magnesium deficiency can affect appetite, muscles, nerves, and the heart. Mild deficiency can be hard to notice at first, but more severe deficiency can become clinically important.
- Loss of appetite, nausea, and fatigue.
- Muscle cramps, numbness, or tingling.
- Abnormal heart rhythms in more severe deficiency.
If intake is too high
Too much magnesium from supplements or medications can cause diarrhea and cramping. Very high intakes are especially risky in kidney disease.
- Diarrhea, nausea, and abdominal cramping.
- Low blood pressure or irregular heartbeat when excess becomes severe.
- Risk is higher with kidney problems or heavy use of magnesium-containing laxatives or antacids.
Adult upper limit: 350 mg/day from supplements and medications
This upper limit does not apply to magnesium naturally present in food.
Common food sources
Magnesium is concentrated in nuts, seeds, legumes, whole grains, and leafy greens.
- Pumpkin seeds, almonds, cashews, and peanuts
- Beans, lentils, and whole grains
- Spinach and other leafy greens
Who may need closer attention
Low intake becomes more likely with certain illnesses, medications, or diets low in whole plant foods.
- People with gastrointestinal disorders or type 2 diabetes
- Older adults and people with alcohol use disorder
- Anyone whose diet is consistently low in legumes, nuts, seeds, and greens
Use extra caution if
Small details change the risk picture with nutrients more than most people expect.
You use laxatives, antacids, or high-dose magnesium powders, or you have kidney disease. Magnesium safety depends a lot on source and context.
Supplement and label notes
Useful context when this nutrient shows up across more than one product.
- Common forms include magnesium oxide, citrate, glycinate, and chloride.
- Laxatives and antacids can add a lot of magnesium without looking like classic supplements.
- If diarrhea starts after a supplement, dose or form is often the problem.
Daily Value targets in SuppMap
These are the same label-style Daily Value targets used in the app.
Official references
These pages were used to draft the summaries on this guide.
Educational only. These pages are not a diagnosis or a substitute for personal medical care.
More guides
Keep moving through the rest of the Daily Value chart from here.