Magnesium for cramps and restless legs, what the trials found

Up to 60% of adults say they've had leg cramps at some point, and they get more common with age [1]. Magnesium is the most studied supplement for them [1].

For everyday night cramps in older adults, magnesium has done no better than a placebo. For restless legs, a few small trials found some benefit.

Does magnesium help with leg cramps?

Not much, in the largest trials so far. A 2020 Cochrane review pooled 11 trials with 735 people. For cramps with no clear cause, mostly in adults in their 60s, magnesium made little difference to how often cramps came, how bad they were or how long they lasted [2].

The reviewers concluded it's unlikely that magnesium gives older adults a meaningful reduction in cramps [2]. A 2026 Finnish trial, published after the review, found the same. In 121 adults aged 50 to 85, 250 mg of magnesium a day for 4 weeks didn't reduce cramps more than a placebo [1].

For cramps in pregnancy, the five trials disagreed and couldn't be pooled, so Cochrane called the evidence conflicting. It found no trials of magnesium for cramps after exercise [2].

So why do many people feel it helps? In an Israeli trial of 94 adults with night cramps, weekly cramps fell from about 8 to 4 on magnesium oxide, and from about 9 to 5 on a placebo. The researchers put the drop down mostly to the placebo effect [3].

Does magnesium help restless legs?

Possibly. Restless legs syndrome causes a strong urge to move your legs, often with tingling, throbbing or itching. The NHS links it to iron levels and a brain chemical called dopamine [4].

A 2024 review of 10 small trials of supplements for restless legs found that magnesium oxide and vitamin B6 improved symptoms and sleep quality. Half of the trials had a high risk of bias, so the authors called for better studies [5].

Which magnesium is best for cramps?

We found no trial comparing forms for cramps. The cramp trials above used magnesium oxide and magnesium hydrochloride, and the restless legs trials mostly used oxide [1][3][5].

Our guide to magnesium glycinate vs citrate covers how the common forms differ.

What else helps leg cramps?

Stretching. The NHS says stretching and massaging the muscle may ease a cramp, and regular calf stretches may reduce how often they happen [6]. Cramps can last from a few seconds to 10 minutes, and most go away on their own [6].

In the Finnish trial, knee-high compression stockings worn during the day cut weekly cramps more than a placebo, and fewer people woke at night [1]. Some people found them uncomfortable and stopped.

For restless legs, the NHS suggests a warm bath or heat pads before bed, walking or stretching during symptoms, and no caffeine after midday [4].

Is it safe to take magnesium for cramps?

The NHS says taking 400 mg or less of magnesium a day from supplements is unlikely to cause harm, and more than that can cause diarrhoea [7]. In the cramp trials, stomach and bowel side effects such as diarrhoea affected 11% to 37% of people taking magnesium, against 10% to 14% on placebo [2].

Our guide to magnesium side effects covers who should check with a GP first.

Where Nooroots fits

Nooroots Triple Magnesium is a food supplement with magnesium glycinate, citrate and malate, in three capsules a day. It's for topping up your daily intake alongside a varied diet.

Magnesium contributes to a reduction of tiredness and fatigue and to normal psychological function [8]. Our guide to how much magnesium per day explains the daily amounts.

Frequently asked questions

Does magnesium help with cramps?

For everyday night cramps in older adults, trials found magnesium worked no better than a placebo [1][2][3].

Does magnesium help restless legs?

A 2024 review of small trials found magnesium oxide improved restless legs symptoms and sleep, but half the trials had a high risk of bias [5].

Which magnesium is best for leg cramps?

Trials of oxide and hydrochloride didn't reduce night cramps in older adults more than a placebo [1][3]. We found no trial comparing forms for cramps.

Is low magnesium a cause of leg cramps?

The NHS lists ageing, some medicines and not drinking enough fluids among the causes, and says the reason for some cramps is unknown [6]. It doesn't list low magnesium.

What stops leg cramps at night?

Stretching and massaging the muscle may ease a cramp, and regular calf stretches may make them less frequent [6]. Compression stockings reduced cramps in one trial of older adults [1].

Read more in our guide to magnesium deficiency symptoms.

References

Every study here is listed so you can read it yourself. This guide is for general information and doesn't replace advice from your GP or pharmacist. We check it again at least every six months.

1. Kuusipalo A, Laitila J, Lehtonen E, et al. (2026). Secondary prevention of leg cramps using compression stockings or magnesium supplements: a three-arm randomized clinical trial. Trials 27(1). PMID 41680812
2. Garrison SR, Korownyk CS, Kolber MR, et al. (2020). Magnesium for skeletal muscle cramps. Cochrane Database of Systematic Reviews 9: CD009402. PMID 32956536
3. Roguin Maor N, Alperin M, Shturman E, et al. (2017). Effect of magnesium oxide supplementation on nocturnal leg cramps: a randomized clinical trial. JAMA Internal Medicine 177(5): 617–623. PMID 28241153
4. NHS. Restless legs syndrome. Page last reviewed 22 September 2025. Accessed 26 October 2026. nhs.uk/conditions/restless-legs-syndrome
5. González-Parejo P, Martín-Núñez J, Cabrera-Martos I, Valenza MC (2024). Effects of dietary supplementation in patients with restless legs syndrome: a systematic review. Nutrients 16(14): 2315. PMID 39064758
6. NHS. Leg cramps. Page last reviewed 1 December 2023. Accessed 26 October 2026. nhs.uk/conditions/leg-cramps
7. NHS. Vitamins and minerals: others (magnesium and zinc sections). Page last reviewed 3 August 2020. Accessed 26 October 2026. nhs.uk
8. Department of Health and Social Care. Great Britain nutrition and health claims (NHC) register, spreadsheet of 19 May 2026. Accessed 26 October 2026. gov.uk