How much magnesium per day? Dosage for adults
How much magnesium per day do adults need?
The Nordic nutrition recommendations set a daily requirement of around 280 mg for women and 350 mg for men. That applies to total intake – food plus any supplements. Needs may increase with hard training, pregnancy and breastfeeding.
| Group | Recommended intake (mg/day) |
|---|---|
| Women (adults) | 280 |
| Men (adults) | 350 |
| Pregnant women | Increased need, consult your healthcare provider |
| Children (varies with age) | 65–280 |
To read more about children and pregnancy, there is a dedicated guide on magnesium during pregnancy and for children.
How much magnesium from supplements?
EFSA's upper limit for magnesium from supplements is 250 mg per day, on top of the diet. The limit exists because high doses draw water into the gut and cause loose stools. Magnesium from food does not count towards it, since it is absorbed more slowly and regulated by the body.
How to work out your own needs
- Estimate how much you get from food – if you eat nuts, seeds, whole grains and greens daily, you are often in good shape.
- Compare against the recommendation for your group.
- Fill the gap with a supplement if you need to, but stay under 250 mg from capsules.
If you need inspiration for your diet, see the list of magnesium-rich foods.
A daily dose of VitaNord Magnesium fills the gap and contributes to a reduction of tiredness and normal muscle function – within safe levels.
See current price »When should you take your magnesium dose?
Timing matters less for total intake, but it can affect the effect. Many take it in the evening to wind down and sleep, others in the morning for energy. Splitting the dose also reduces the risk of stomach upset. More on this in when to take magnesium.
What happens with too much magnesium?
Excess from supplements usually causes loose stools, bloating and stomach cramps. Genuinely high blood levels are rare in healthy people, but can occur with reduced kidney function. Read more about the limits in the article on magnesium and side effects.
What happens with too little magnesium?
Low intake over a longer period can cause tiredness, muscle twitches, cramps and poorer sleep. Early signs are often vague. If they sound familiar, see symptoms of magnesium deficiency. If you want to find a good supplement, compare in the guide to the best magnesium.
Does your life situation affect your needs?
The recommendations are reference values for healthy adults. Several situations raise needs or losses, and then it can make sense to aim for the upper end of the range.
- Hard training: magnesium is lost through sweat, and the muscles work harder.
- Pregnancy and breastfeeding: needs increase – follow your healthcare provider's advice.
- High stress: stress is linked to increased excretion of magnesium.
- Gut problems: impaired absorption leads to lower levels.
How to split your dose
The body absorbs magnesium best in smaller amounts at a time. If you are taking a higher supplement dose, it is therefore smart to split it – for example half in the morning and half in the evening. That improves absorption and reduces the risk of loose stools compared with taking it all at once. Take it with a meal if you can.
How long should you take magnesium?
Magnesium is a nutrient you need throughout life, not a course lasting a few weeks. If you take a supplement to fill a gap in your diet, you can do so on an ongoing basis for as long as your intake is too low. If you improve your diet so that it covers your needs, you can taper off. There is no fixed time limit, but always stay within the recommended dose.
A simple rule of thumb to remember
If you'd rather not do the maths: aim for a total of around 300–350 mg per day, keep the supplement portion under 250 mg, base your intake on magnesium-rich food and split the dose if you take more. That is enough for the vast majority without any hassle.
Can a blood test show whether you are deficient?
Only partly. A standard blood test measures magnesium in serum, but only a small part of the body's magnesium is in the blood – the rest sits in bone and muscle. The body keeps the blood level stable by moving magnesium from its stores, which means the test can look normal despite low reserves. A normal result therefore doesn't rule out low intake.
In practice, it is often more useful to look at your diet and any symptoms than to fixate on a serum test. If you suspect a deficiency for medical reasons, raise it with your doctor, who can decide which tests are relevant.
How to get started the easy way
- Look at your diet first – nuts, seeds, whole grains, pulses and greens.
- If you need to top up, start with a lower dose for a week or so.
- Increase if needed, but stay under 250 mg from supplements.
- Take it with food and split the dose if you notice stomach upset.
With that order of priorities, you get the effect without overdoing it. If you want to choose a product, compare in the guide to the best magnesium.
With or without food?
You can take magnesium with or without food, but with a meal is usually best. Food makes absorption smoother and reduces the risk of loose stools and nausea that can otherwise occur on an empty stomach. If you have chosen an evening dose for sleep, taking it with your evening meal or a small snack works well.
Frequently asked questions
How much magnesium should I take per day?
Adults need a total of around 280 mg (women) to 350 mg (men) per day, food and supplements included. From supplements you should stay under 250 mg per day according to EFSA. Factor in what your diet provides and only fill the gap. If you have increased needs due to training or pregnancy, check the level with your healthcare provider.
Can you take 400 mg of magnesium a day?
A total intake of 400 mg from food and supplements is reasonable for many adults, but the supplement portion itself should stay under 250 mg per day according to EFSA to avoid loose stools. If you want to take more via capsules, split the dose and take it with food, and check with a doctor if you are unsure about your kidney function.
Should the magnesium dose be taken in the morning or evening?
For total intake it makes no difference. For the effect, timing can matter: the evening suits winding down and sleep, the morning suits energy. If you get stomach upset, splitting the dose often helps – half in the morning, half in the evening. Always try to take it with food.
Does everyone need a magnesium supplement?
No. If you eat a varied diet with nuts, seeds, whole grains, pulses and green vegetables, you usually meet your needs through food. A supplement is mainly relevant with low intake, increased needs or a confirmed deficiency. If in doubt, start with your diet and only top up if you don't reach the recommendation.