# Magnesium: what is shown and what is not

With a normal diet, magnesium deficiency is rare.[^1] On cramps, sleep and weight, research is far more cautious than many packs suggest.

**This is information, not a recommendation.** We do not advise you to take anything. **Under 18 or with an eating disorder, including a past one:** this text is not aimed at you, and you will find places to turn to under [When to get medical advice](https://kostenlos-abnehmen.de/en/wissen/aerztlicher-rat). During pregnancy or breastfeeding, with kidney disease or on medication, ask a doctor first.

## How much the body needs

The German Nutrition Society (DGE) estimates 350 mg a day for adult men and 300 mg for women.[^1] EFSA arrives at the same figures.[^2] In the German National Nutrition Survey II, the median was 334 to 378 mg a day in women, depending on age, and 389 to 454 mg in men from 25.[^2]

Good sources are whole grains, pulses and nuts.

## What may be said in the EU

These are among the authorised claims, and only for foods that are at least a source of magnesium as defined in the regulation:[^3]

- “Magnesium contributes to normal muscle function”
- “Magnesium contributes to a reduction of tiredness and fatigue”
- “Magnesium contributes to electrolyte balance”
- “Magnesium contributes to normal energy-yielding metabolism”
- “Magnesium contributes to normal protein synthesis”
- “Magnesium contributes to the maintenance of normal bones”

They describe what the body needs magnesium for. They do not say that extra magnesium changes anything if you are well supplied. Claims on blood pressure, blood sugar and the immune system are not authorised.[^4]

## What studies show

| Topic | What was studied | Result |
| --- | --- | --- |
| Cramps | Cochrane review of 11 trials with 735 people | In older adults a noticeable benefit is unlikely. In pregnancy the data conflict. There was no randomised trial on cramps during exercise[^5] |
| Sleep | 3 trials with 151 older adults | Fell asleep about 17 minutes faster, sleep time did not change reliably. Data quality was low to very low[^6] |
| Performance | Review of minerals in sport, 22 papers on magnesium | Little evidence overall of better performance. Magnesium is at least among the better studied substances[^7] |
| Muscle soreness | Review of 4 studies | The studies report less soreness, but the basis is small[^8] |
| Weight | 32 trials, and 78 trials in a newer analysis | No overall change in weight, only in subgroups.[^9] The newer analysis saw a small difference in weight but none in body fat percentage or waist size[^10] |

There is no authorised claim on losing weight.[^4]

## Upper limits and tolerance

The BfR proposes at most 250 mg a day for food supplements, split into two or more portions. The figure comes from the fact that mild diarrhoea can occur from about 300 to 365 mg extra. Magnesium from normal food has caused no problems so far.[^2] In the US, the limit for magnesium from products is 350 mg for adults. High doses can cause diarrhoea, nausea and abdominal cramping.[^11]

In the cramp trials, 11 to 37% of participants had mainly stomach and gut complaints, compared with 10 to 14% on placebo.[^5]

## When to ask a doctor

- **Kidney disease:** The kidneys control how much magnesium is excreted. With severe impairment, magnesium can build up.[^12]
- **Medication:** Magnesium can interact with oral bisphosphonates and with tetracycline and quinolone antibiotics. Diuretics and proton pump inhibitors can affect magnesium status.[^11] A review also names calcium channel blockers.[^12]
- **Frequent cramps or severe tiredness:** These should be looked at rather than covered up with a product. See [When to get medical advice](https://kostenlos-abnehmen.de/en/wissen/aerztlicher-rat).

## Sources

[^1]: [DGE (German Nutrition Society): reference values for magnesium](https://www.dge.de/wissenschaft/referenzwerte/magnesium/)
[^2]: [BfR: Maximum level proposals for magnesium in foods including food supplements](https://www.bfr.bund.de/cm/343/hoechstmengenvorschlaege-fuer-magnesium-in-lebensmitteln-inklusive-nahrungsergaenzungsmitteln.pdf)
[^3]: [Regulation (EU) No 432/2012 establishing a list of permitted health claims, consolidated version](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02012R0432-20210517)
[^4]: [European Commission: EU Register on nutrition and health claims, accessed November 2026](https://ec.europa.eu/food/food-feed-portal/screen/health-claims/eu-register)
[^5]: [Garrison SR et al.: Magnesium for skeletal muscle cramps. Cochrane Database Syst Rev, 2020](https://pubmed.ncbi.nlm.nih.gov/32956536/)
[^6]: [Mah J et al.: Oral magnesium supplementation for insomnia in older adults: a Systematic Review & Meta-Analysis. BMC Complement Med Ther, 2021](https://pubmed.ncbi.nlm.nih.gov/33865376/)
[^7]: [Heffernan SM et al.: The Role of Mineral and Trace Element Supplementation in Exercise and Athletic Performance: A Systematic Review. Nutrients, 2019](https://pubmed.ncbi.nlm.nih.gov/30909645/)
[^8]: [Tarsitano MG et al.: Effects of magnesium supplementation on muscle soreness in different type of physical activities: a systematic review. J Transl Med, 2024](https://pubmed.ncbi.nlm.nih.gov/38970118/)
[^9]: [Askari M et al.: The effects of magnesium supplementation on obesity measures in adults: a systematic review and dose-response meta-analysis of randomized controlled trials. Crit Rev Food Sci Nutr, 2021](https://pubmed.ncbi.nlm.nih.gov/32654500/)
[^10]: [Mohammadi S et al.: Comprehensive Effects of Magnesium Supplementation on Cardiometabolic Risk Factors: A Systematic Review and Dose-Response Meta-Analysis. Nutrients, 2026](https://pubmed.ncbi.nlm.nih.gov/42588058/)
[^11]: [NIH Office of Dietary Supplements: Magnesium, Fact Sheet for Health Professionals](https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/)
[^12]: [Gröber U et al.: Magnesium in Prevention and Therapy. Nutrients, 2015](https://pubmed.ncbi.nlm.nih.gov/26404370/)

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Last updated: November 2026. This is general information and not medical advice.

Original article: https://kostenlos-abnehmen.de/en/wissen/magnesium