How high is the daily magnesium requirement?
For magnesium, estimated values for an adequate daily intake are used. An individual minimum requirement is difficult to determine exactly – among other reasons because only around one per cent of the total body magnesium is in the blood serum, while the majority is bound in bones, musculature and other cells. An isolated serum value therefore reflects the supply status only to a limited extent.2
For adults, 300 mg per day apply for women and 350 mg per day for men. Differences between groups of people are related, among other things, to age, sex, body mass and muscle volume.1,2
| Group / age band | Estimated value for daily intake |
|---|---|
| Children (4 to under 10 years) | 190–240 mg |
| Adolescents (15 to under 19 years) | female 260 mg / male 330 mg |
| Adult women (from 19 years) | 300 mg |
| Adult men (from 19 years) | 350 mg |
| Pregnant women (from 19 years) | 300 mg |
| Breastfeeding women | 300 mg |
Estimated values for an adequate intake. Sources: 1,2
are the DGE estimated values for an adequate magnesium intake in adults – 300 mg for women, 350 mg for men.1
The question of why no blanket higher value is set during pregnancy is dealt with deliberately in a separate article.
Why does the body need magnesium every day?
The body cannot produce magnesium itself. At the same time, minerals are continuously lost through urine, stool and sweat. A regular magnesium intake through the diet is therefore necessary.4
As a cofactor, magnesium is involved in well over 300 enzymatic reactions. These include metabolic processes around energy, DNA and protein synthesis as well as processes in nerve and muscle cells. A large part of the magnesium is moreover located in bone tissue.3
enzymatic reactions in the body run with magnesium as a cofactor – which explains why a regular supply is important.3
This physiological role does not, however, mean that a higher magnesium intake automatically produces more effect or better well-being. What is decisive is a supply that meets requirements, not as much magnesium as possible.
Do you have to take magnesium every day?
On the question of whether one should take magnesium daily, a distinction must be made between magnesium from food and taking magnesium as a supplement. The daily supply through the diet is necessary. A daily capsule, tablet or other magnesium preparation is, by contrast, not required for everyone.4,5
Data from the German National Nutrition Survey II show an average magnesium intake of 284 mg per day in women and 345 mg per day in men. With a balanced diet and intact organ function, a purely diet-related magnesium deficiency is accordingly rare.2
For healthy people without a diagnosed magnesium deficiency, a blanket daily supplementation is therefore not automatically associated with an additional physiological benefit.5 What causes a deficiency can have and how a magnesium deficiency makes itself felt are covered in a separate guide.
When can the magnesium requirement change?
Magnesium requirement and magnesium absorption can be influenced by various factors. Certain diseases, medicines or increased losses can change the supply. Among the possible influencing factors named are proton pump inhibitors, diuretics and metabolic derangements in diabetes mellitus.2,3
In high-performance athletes with very high training volumes, heavy sweat losses can temporarily influence the magnesium balance. For moderately active people, however, no general rule to take additional magnesium can be derived from this.7
For pregnant and breastfeeding women of legal age, the underlying DGE position sets no blanket higher estimated value – both groups are listed at 300 mg per day.2 More on this in the article Why no magnesium during pregnancy?.
What dosage applies to magnesium supplements?
There is no universally applicable magnesium dosage for every person. How much magnesium is needed depends on the total magnesium intake through the diet, individual factors, possible losses and the reason for taking it.
For food supplements, the German Federal Institute for Risk Assessment proposes a maximum amount of 250 mg of magnesium per recommended daily amount. This amount should be spread over at least two portions across the day.6
is the maximum amount the BfR proposes for magnesium per recommended daily amount in food supplements – spread over at least two portions. This is a maximum-level proposal, not a recommendation for everyone.6
The 250 mg are not a blanket recommendation that every person should take in exactly this amount in addition – they are a maximum-level proposal for food supplements.
Magnesium is available commercially as a capsule, tablet, powder or drinking solution and in different magnesium compounds. Which form and which active substance are appropriate in an individual case is a different question from the pure daily requirement. Magnesium stearate, in turn, is not the same as a magnesium supplement for magnesium intake – more on this in the article Magnesium stearate: a bad reputation without cause?.
Taking magnesium: can you take too much?
Yes. Too much magnesium from food supplements can cause side effects. Larger single doses of magnesium salts can exceed the absorption capacity in the small intestine. Magnesium that is not absorbed remains in the gut and can trigger gastrointestinal complaints, abdominal cramps and diarrhoea.3,4
The Verbraucherzentrale (German consumer organisation) points out that with an additional magnesium intake of 300 mg per day or more, diarrhoea and gastrointestinal complaints can occur.4 This is one of the reasons why the BfR maximum-level proposal for food supplements is already set at 250 mg per recommended daily amount.6
The simultaneous intake of other nutrients or medicines can also be relevant. Which combinations can be problematic is covered in the guide What should not be taken together with magnesium?.
What role does magnesium play in muscle cramps and sport?
Many people take magnesium because they hope for an effect against nocturnal calf cramps or muscular tension. The physiological role of magnesium in nerve and muscle cells does not, however, automatically mean that a magnesium supplement treats idiopathic muscle cramps.3
A Cochrane review shows that magnesium probably has no clinically relevant benefit for idiopathic muscle cramps in older adults. For exercise-induced muscle cramps in people doing sport, too, there is no established general recommendation for magnesium supplementation.7,8
The DGN guideline likewise assesses the efficacy of magnesium for idiopathic cramps as not sufficiently proven. For acute cramps, stretching and the activation of the antagonist musculature are named, among other things.9
How can the magnesium intake be covered through the diet?
For the daily magnesium intake, food plays the most important role. Good sources of magnesium are, above all, wholegrain products, pulses, green leafy vegetables, nuts and seeds.3
With cereals, processing can reduce the magnesium content when magnesium-rich outer layers are removed. Wholegrain products are therefore usually richer in magnesium than heavily refined cereal products.3
A detailed food table does not belong in this daily-requirement article. Which magnesium-rich foods provide particularly high amounts and where the most magnesium is found are covered in a separate article. Anyone interested in the interplay with potassium will find further information in the article Magnesium and potassium – why do we need them?.
