How much magnesium per day do you need? For most adults, the Recommended Dietary Allowance (RDA) falls between 310 and 420 mg a day from all sources combined, depending on sex and life stage. Separately, the Food and Nutrition Board sets an upper limit of 350 mg a day for magnesium from supplements, because higher supplemental amounts can upset your stomach. Food magnesium does not count toward that limit. This guide explains both numbers, how to estimate what you already get from food, and how to choose a supplement amount that fits.
Key takeaways
- For most adults, the Recommended Dietary Allowance (RDA) falls between 310 and 420 mg a day from all sources combined, depending on sex and life stage.
- Magnesium from supplements has its own upper limit for adults: 350 mg a day, set mainly to avoid stomach upset. Food magnesium does not count toward it.
- Many Americans fall short of the RDA, so start by closing the gap with food.
How much magnesium per day: the two numbers that matter
Magnesium guidance is built on two different numbers, and mixing them up is the most common source of confusion.
- The RDA is the total daily amount, from food, drinks and supplements together, that meets the needs of nearly all healthy people. For adults it ranges from 310 to 420 mg depending on sex and life stage, and it is slightly higher during pregnancy.
- The upper limit (UL) for adults is 350 mg a day, and it applies only to magnesium from supplements and medications. It is set mainly to avoid diarrhea, nausea and stomach cramping, which are the usual signs of too much supplemental magnesium.
So you can eat a magnesium-rich diet well above 350 mg and be fine, while a supplement alone that goes above 350 mg is something to discuss with your healthcare provider first.
Are most people getting enough magnesium?
Surveys suggest many people in the United States eat less magnesium than the RDA, so the gap is often worth closing with food first. Diets heavy in refined grains and processed foods tend to be lower in magnesium, because processing strips out much of the mineral. Regular alcohol, heavy sweating, some digestive conditions and certain medications can also raise your needs or increase losses.
Low intake does not usually cause obvious symptoms in the short term. That is why a food-first look at your diet is more useful than guessing from how you feel.
Magnesium in food: where it comes from
Here are some of the richest common sources, based on the NIH Office of Dietary Supplements food table. Amounts are approximate.
| Food | Serving | Magnesium (approx.) |
|---|---|---|
| Pumpkin seeds, roasted | 1 ounce | 156 mg |
| Chia seeds | 1 ounce | 111 mg |
| Almonds, dry roasted | 1 ounce | 80 mg |
| Spinach, boiled | ½ cup | 78 mg |
| Cashews, dry roasted | 1 ounce | 74 mg |
| Black beans, cooked | ½ cup | 60 mg |
| Edamame, shelled, cooked | ½ cup | 50 mg |
| Brown rice, cooked | ½ cup | 42 mg |
| Plain yogurt, low fat | 8 ounces | 42 mg |
A day that includes a handful of nuts or seeds, a serving of beans, leafy greens and whole grains can supply a large share of the RDA before any supplement enters the picture.
How to work out a sensible supplement amount
- Estimate your food intake. A rough tally of a typical day is enough. If your diet is light on the foods above, your gap is probably larger.
- Check everything you already take. Multivitamins, calming blends, electrolyte drinks and some antacids or laxatives contain magnesium. Add them up.
- Compare the supplement total with 350 mg. Staying at or under the upper limit is the simple default. Going above it is a conversation to have with your healthcare provider.
- Choose a form you tolerate. Glycinate is usually the gentlest; citrate and oxide are more likely to loosen stools.
- Take it consistently and give it time. Two to four weeks of daily use tells you far more than a single dose.
How our two magnesium formulas compare
Magnesium Glycinate+ provides 275 mg of magnesium from 2,500 mg of magnesium glycinate in a three-capsule serving, taken once daily before a meal. That keeps the supplement amount under the upper limit, with room for some magnesium from a multivitamin.
Magnesium5+™ provides 500 mg of magnesium per two-capsule serving from five forms, including malate, citrate and glycinate. This amount is above the supplement upper limit described earlier, so talk with your healthcare provider before using it, and do not combine it with other magnesium products unless your provider agrees.
Both are third-party tested, every batch, for purity and potency, and manufactured in USA with globally sourced materials in an NSF-certified, GMP-certified, FDA-registered facility. Learn more on our Our Standards page. To compare the forms in more depth, read Magnesium Malate vs. Glycinate: Why Magnesium5+ Uses Both.
Who should be careful with magnesium supplements?
Your kidneys clear extra magnesium, so anyone with kidney concerns should only use magnesium supplements under a healthcare provider's guidance. Magnesium can also reduce the absorption of some medicines, including certain antibiotics and bone medications, so timing matters if you take them. If you are pregnant or nursing, have a known medical condition, or take prescription medication, check with your provider before starting.
Frequently asked questions about how much magnesium per day
Is 500 mg of magnesium a day too much?
From food, no. From supplements, 500 mg is above the 350 mg upper limit set for adults, mainly because of digestive side effects. Some people use higher amounts under a healthcare provider's guidance, but it should be a deliberate decision, not a default.
Does the upper limit include magnesium from food?
No. The 350 mg upper limit covers only supplements and medications. Magnesium from food and drinks is not counted toward it.
What are signs of too much magnesium from supplements?
The most common signs are loose stools, nausea and stomach cramping. If you notice them, reduce or stop the supplement and talk with your healthcare provider.
Is it better to take magnesium all at once or split it?
Follow your product's label first. Some people find a split amount easier on the stomach, but the label direction is the one to use unless your provider suggests otherwise.
Can I get enough magnesium from food alone?
Many people can, especially with regular nuts, seeds, beans, leafy greens and whole grains. A supplement is a way to fill a gap, not a replacement for those foods.
Related reading from our Wellness Hub
- Does Magnesium Help You Sleep? What the Research Says
- Magnesium: Forms, Timing, and How to Choose
- Magnesium Complex Benefits: Meet Magnesium5+
Sources
- NIH Office of Dietary Supplements: Magnesium Fact Sheet for Health Professionals
- NIH Office of Dietary Supplements: Magnesium Fact Sheet for Consumers
- Blancquaert L, et al. Predicting and Testing Bioavailability of Magnesium Supplements. Nutrients, 2019
Individual results vary.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
