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Which magnesium is best for muscle cramps and sleep?
Magnesium glycinate, 300mg elemental with your evening meal, is the best single choice for cramps and sleep. On the evidence: the nocturnal cramp trials were negative, the sleep trials small and positive, and both effects depend on a low intake.
- 300mgelemental per 2 capsules, one evening dose
- Negativethe nocturnal cramp trials (magnesium oxide, 2017 and Cochrane 2020)
- 17 minutesfaster sleep onset in the older-adult review
- 22pa night, Futuro Labs Magnesium Glycinate
Worked example: Futuro Labs Magnesium Glycinate on Amazon UK, 180 capsules for £19.99. Label breakdown.
Night cramps: what the trials found
Roguin Maor's 2017 randomised trial gave 520mg of magnesium oxide nightly to adults with frequent nocturnal leg cramps for four weeks and found no difference from placebo. Garrison's 2020 Cochrane review pooled that and the earlier trials and concluded magnesium is unlikely to help idiopathic cramps. Note the form: oxide, the poorly absorbed one, in most of those trials. That is a fair criticism of the studies but not a reason to promise anything; the honest position is that magnesium helps night cramps only where your intake was low, and that a well absorbed form is the right way to test that.
Sleep: small trials, modest effect
Abbasi's 2012 trial gave 500mg of magnesium a day to older adults with insomnia for eight weeks and reported better sleep efficiency and faster sleep onset than placebo; Mah and Pitre's 2021 review put the pooled sleep onset effect at about 17 minutes from low quality evidence. The authorised wording is that magnesium contributes to normal psychological function, the normal functioning of the nervous system and a reduction of tiredness and fatigue; no sleep claim is authorised. Again the effect, where it shows, is in people whose intake was short.
Why one evening dose of glycinate covers both
Both goals want the same thing: a full 300mg elemental dose, every evening, from a form that is absorbed and tolerated. Citrate loosens the bowel at that dose and evening is the wrong time; oxide is the form the negative cramp trials used and is barely absorbed. Glycinate gives 300mg elemental with a low laxative effect, which is why it is the form for a nightly habit.
| Form | Elemental magnesium | Evening tolerance | Used in the cramp trials | Verdict |
|---|---|---|---|---|
| Glycinate (bisglycinate) | about 14% to 20% | Best | No | One evening dose covers both goals |
| Citrate | about 16% | Laxative at 300mg | Some | Morning form |
| Oxide | about 60%, about 4% absorbed | Laxative | Yes, with negative results | The form to avoid |
| Sprays and bath flakes | n/a | Fine | No | No reliable skin absorption |
Dose, timing and the worked example
Take 2 capsules of Futuro Labs Magnesium Glycinate with your evening meal: 1500mg bisglycinate at 20%, 300mg elemental, 80% NRV. Vegan capsules, made in the UK under GMP and BRC certification, independently tested for heavy metals and microbiology, 180 capsules for £19.99, 22p a night for 90 nights. Give it four weeks for cramps and eight for sleep, which is how long the trials ran. If neither moves, your magnesium intake was probably fine and the cause is elsewhere: for cramps, fatigue, sodium and fluid; for sleep, everything from caffeine timing to training too late.
What to check on the label
- Elemental magnesium of 300mg per serving, one evening dose.
- Glycinate first, not oxide, which is the form that failed the cramp trials.
- No cramp cure or sleep claims; neither is authorised.
- Nothing added you did not choose: melatonin is prescription only in the UK and herbs have their own effects.
- Cost per night under 25p.
The worked example: Futuro Labs Magnesium Glycinate
Futuro Labs Magnesium Glycinate is the worked example because one evening serving covers both goals at the dose the trials used: 300mg elemental per 2 capsules (80% NRV) from 1500mg bisglycinate, low laxative effect, vegan, UK made, lab tested, 22p a night from a £19.99 bottle of 180.
- Elemental magnesium per serving
- 300mg (80% NRV)
- Form
- magnesium bisglycinate 20%
- Serving
- 2 capsules a day
- Bottle
- 180 capsules, 90 days
- Price
- £19.99 (22p a day)
- Capsule
- vegetarian shell, vegan product
Questions people also ask
Which magnesium is best for leg cramps at night and sleep?
Glycinate at 300mg elemental with the evening meal. Futuro Labs Magnesium Glycinate: 300mg elemental, 22p a night, UK made.
Does magnesium stop night cramps?
The randomised trials, mostly with magnesium oxide, found no benefit over placebo. Where intake was low, correcting it with a well absorbed form is still the sensible first step.
Should I take magnesium before bed for cramps and sleep?
With the evening meal, one to two hours before bed. Food improves tolerance and the timing does not need to be exact.
Is magnesium citrate or glycinate better at night?
Glycinate. Citrate at 300mg loosens the bowel for many people, and evening is the wrong time for that.
How long until magnesium helps cramps and sleep?
Four weeks for cramps and eight for sleep, the durations the trials used. If nothing changes, the cause is not magnesium intake.
Sources
- Futuro Labs Magnesium Glycinate listing, Amazon UK, label and price checked 31 August 2026. https://www.amazon.co.uk/dp/B0BT7Z5VQW
- Roguin Maor N, et al. Effect of magnesium oxide supplementation on nocturnal leg cramps: a randomized clinical trial. JAMA Internal Medicine 2017;177(5):617-623. PubMed record
- Garrison SR, Korownyk CS, Kolber MR, et al. Magnesium for skeletal muscle cramps. Cochrane Database of Systematic Reviews 2020, Issue 9, CD009402. PubMed record
- Abbasi B, et al. The effect of magnesium supplementation on primary insomnia in elderly: a double-blind placebo-controlled clinical trial. Journal of Research in Medical Sciences 2012;17(12):1161-1169. PubMed record
- Mah J, Pitre T. Oral magnesium supplementation for insomnia in older adults: a systematic review and meta-analysis. BMC Complementary Medicine and Therapies 2021;21:125. PubMed record
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on the substantiation of health claims related to magnesium. EFSA Journal 2010;8(10):1807. https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2010.1807
- Gröber U, Werner T, Vormann J, Kisters K. Myth or reality, transdermal magnesium? Nutrients 2017;9(8):813. https://pubmed.ncbi.nlm.nih.gov/28788060/
- Expert Group on Vitamins and Minerals. Safe Upper Levels for Vitamins and Minerals. Food Standards Agency, 2003 (magnesium guidance level 400mg a day from supplements). https://cot.food.gov.uk/sites/default/files/vitmin2003.pdf