Magnesium Guide: Best Foods, Supplement Types and Safe Doses
This magnesium guide covers a mineral that takes part in hundreds of processes in your body, from muscle and nerve function to blood sugar and blood pressure control. Many Americans eat less than recommended. The good news: some of the richest sources are easy, tasty foods.
Health note: This article is for general education only. It is not medical advice and it does not replace care from your doctor. Foods and supplements are not a substitute for prescribed treatment. Talk to a licensed health professional before changing your diet, medicines or supplements, especially if you are pregnant, take prescription drugs or have a chronic condition.
- Adults need 310 to 420 mg a day, depending on age and sex.
- The upper limit from supplements and medicines is 350 mg a day. Food magnesium does not count toward it.
- Pumpkin seeds, chia, almonds, spinach and beans are top food sources.
Magnesium guide: how much you need
| Age | Men | Women |
|---|---|---|
| 19 to 30 years | 400 mg | 310 mg |
| 31 years and older | 420 mg | 320 mg |
Source: NIH Office of Dietary Supplements.
Richest food sources
| Food | Serving | Magnesium |
|---|---|---|
| Pumpkin seeds | 1 ounce | 156 mg |
| Chia seeds | 1 ounce | 111 mg |
| Almonds, dry roasted | 1 ounce | 80 mg |
| Spinach, boiled | 1/2 cup | 78 mg |
| Cashews, dry roasted | 1 ounce | 74 mg |
| Black beans, cooked | 1/2 cup | 60 mg |
| Edamame, cooked | 1/2 cup | 50 mg |
What magnesium may help with
Mixed evidence
The NIH notes that magnesium supplements might lower blood pressure by a small amount, and people with higher magnesium intake tend to have lower risk of heart disease, stroke and type 2 diabetes. Magnesium is also involved in bone health. Evidence for popular uses like sleep, anxiety and leg cramps is limited.
Supplement forms compared
- Better absorbed: magnesium citrate, aspartate, lactate and chloride, which dissolve well in liquid.
- Less absorbed: magnesium oxide and sulfate.
- Most likely to cause diarrhea: carbonate, chloride, gluconate and oxide, especially at high doses.
Safety and interactions
Stronger evidence
- Too much from supplements causes diarrhea, nausea and cramps. Very high doses can be dangerous, especially with kidney disease.
- Osteoporosis drugs (bisphosphonates like alendronate): take at least 2 hours apart from magnesium.
- Some antibiotics (tetracyclines, quinolones): separate by 2 to 4 hours.
- Diuretics can raise or lower magnesium levels.
- Acid reducers (PPIs) used for more than a year can lower magnesium.
- Remember that antacids and laxatives often contain magnesium too.
For tips on picking any supplement, see our smart supplement guide and vitamin D guide.
The bottom line
The bottom line of this magnesium guide: eat seeds, nuts, beans and greens first, keep supplements under 350 mg a day, and check interactions with your pharmacist. Use this magnesium guide whenever you compare products.
Frequently asked questions
What is the best time to take magnesium?
Take it with food to reduce stomach upset, and keep it 2 or more hours apart from medicines it interacts with.
Does magnesium help with sleep?
Evidence is limited. Magnesium-rich foods are healthy, but good sleep habits have much stronger evidence.
Can I get too much magnesium from food?
Healthy kidneys remove extra magnesium from food, so food is not a concern. The 350 mg upper limit applies to supplements and medicines.
Your next step
Add one magnesium-rich snack a day this week, such as an ounce of pumpkin seeds or almonds, before considering a supplement.
Common myths covered in this magnesium guide
- Myth: Everyone needs a magnesium supplement. Fact: Many people can meet their needs with seeds, nuts, beans and greens.
- Myth: Magnesium oxide is the best form. Fact: It is less absorbed than citrate or chloride forms.
- Myth: Food magnesium can reach toxic levels. Fact: Healthy kidneys remove extra magnesium from food. The upper limit in this magnesium guide applies to supplements.
Sources
- NIH Office of Dietary Supplements: Magnesium (Health Professional)
- NIH Office of Dietary Supplements: Magnesium (Consumer)
About the author: Reginaldo Encarnacao is an independent health writer who researches public sources such as the National Institutes of Health (NIH). He is not a doctor, pharmacist or dietitian.
Medical disclaimer: The information on this page is for educational purposes only and is not intended to diagnose, treat, cure or prevent any disease. Statements about dietary supplements have not been evaluated by the Food and Drug Administration. Individual results vary. See our full disclaimer.
