Minerals · 5 min read ·

Magnesium: for cramps, sleep and blood pressure?

Magnesium is one of the most popular minerals from the pharmacy. Does it help cramps, sleep or blood pressure? And how much is too much?

24.305 Mg 12

In a nutshell

1How much you need

EFSA recommendation 350 / 300 mg EFSA set the adequate daily intake of magnesium at 350 mg for men and 300 mg for women.4
Upper level 250 mg The upper level for magnesium from supplements and fortified foods is 250 mg a day, split into several doses; magnesium from ordinary food does not count towards it. Higher doses can cause mild diarrhoea.3

Which forms of magnesium are absorbed best is covered below under Forms and absorption; an overview of all vitamins and minerals is in the article Bioavailability.

2Cramps

Strong evidence 11 studies A Cochrane review (11 studies, 735 people): in older people with night cramps, magnesium hardly reduced the number of cramps compared with placebo. For exercise cramps, the authors found no randomised trial.1

3Sleep

Weak evidence −17 min A summary of 3 small studies with 151 older people: with magnesium they fell asleep 17 minutes faster; total sleep time did not change significantly. According to the authors, the quality of the evidence is insufficient.5

4Blood pressure

Moderate evidence −2 mmHg A summary of 34 studies with 2,028 people: magnesium (368 mg a day on average for 3 months) lowered systolic blood pressure by 2 mmHg and diastolic by 1.8 mmHg.2

5Forms and absorption

Moderate evidence 14 studies A systematic review of 14 studies: organic forms of magnesium are absorbed better than inorganic ones, and the share absorbed falls as the dose rises. In healthy people without a deficiency, however, any supplement maintains normal levels; in older and sick people this is not certain.6
Weak evidence — small studies 4% In one study only about 4% of magnesium oxide was absorbed, and considerably more of magnesium chloride, lactate and aspartate. In another, 60-day study of 46 people, oxide did not differ from placebo, while citrate and an amino-acid chelate raised magnesium in the body — citrate the most.7,8
Weak evidence — one study 80 people Magnesium L-threonate, a newer form, improved deep sleep measured by a smart ring and how people felt during the day after 3 weeks in a study of 80 people with sleep problems. So far it is a single study.9

In the EU, supplements may contain magnesium in many forms — including oxide, carbonate, hydroxide, chloride, sulphate, citrate, lactate, gluconate, bisglycinate, malate, taurate or L-threonate.10 The 250 mg upper level applies to readily dissolving salts (chloride, sulphate, aspartate, lactate) and magnesium oxide in supplements, not to magnesium from food.11

What to take from this

Sources

Written on , based on studies available at that date. Newer research may change the conclusions.

  1. Garrison S. R. et al. (2020). Magnesium for skeletal muscle cramps. Cochrane Database Syst Rev CD009402. doi.org/10.1002/14651858.CD009402.pub3
  2. Zhang X. et al. (2016). Effects of magnesium supplementation on blood pressure: a meta-analysis of randomized double-blind placebo-controlled trials. Hypertension 68:324–333. doi.org/10.1161/HYPERTENSIONAHA.116.07664
  3. BfR (2022). Proposed maximum levels for the addition of magnesium to foods including food supplements (SCF 2001 upper level). bfr.bund.de
  4. EFSA (2015). Dietary reference values: magnesium and phosphorus (press release on the scientific opinion). efsa.europa.eu
  5. Mah J., Pitre T. (2021). Oral magnesium supplementation for insomnia in older adults: a systematic review & meta-analysis. BMC Complement Med Ther 21:125. doi.org/10.1186/s12906-021-03297-z
  6. Pardo M. R. et al. (2021). Bioavailability of magnesium food supplements: a systematic review. Nutrition 89:111294. doi.org/10.1016/j.nut.2021.111294
  7. Firoz M., Graber M. (2001). Bioavailability of US commercial magnesium preparations. Magnes Res 14:257–262. pubmed.ncbi.nlm.nih.gov/11794633
  8. Walker A. F. et al. (2003). Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnes Res 16:183–191. pubmed.ncbi.nlm.nih.gov/14596323
  9. Hausenblas H. A. et al. (2024). Magnesium-L-threonate improves sleep quality and daytime functioning in adults with self-reported sleep problems: a randomized controlled trial. Sleep Med X 8:100121. doi.org/10.1016/j.sleepx.2024.100121
  10. Directive 2002/46/EC on food supplements, Annex II — forms of vitamins and minerals permitted in supplements (consolidated version 26 Nov 2025). eur-lex.europa.eu
  11. EFSA (2025). Overview on Tolerable Upper Intake Levels as derived by the Scientific Committee on Food (SCF) and the EFSA Panel on Nutrition (version 11). efsa.europa.eu

This is general information and does not replace a doctor. Food supplements are not medicines; buy them from trusted sellers and talk to a doctor if you are ill or take medicines.