Magnesium oxide monohydrate for night leg cramps
What it found
In 175 adults with night leg cramps, a magnesium oxide monohydrate supplement taken daily for 60 days reduced how often cramps happened, how long they lasted and improved sleep more than a placebo.
The authors say it was effective and well tolerated.
What they found
Studies in people
Cramp frequency
Both groups had fewer cramps per week by the end of the study compared with the start. The magnesium oxide monohydrate group had a larger drop than the placebo group, with a reduction of 3.4 episodes versus 2.6 episodes.
Cramp duration
The length of cramp episodes fell in both groups. The magnesium oxide monohydrate group had a bigger reduction than the placebo group.
Pain
Pain scores improved in both groups over the 60 days. There was no difference between the magnesium oxide monohydrate group and the placebo group in how much pain improved.
Sleep quality
Sleep quality improved in both groups. The magnesium oxide monohydrate group had a larger improvement than the placebo group.
Side effects
No adverse events were reported in the magnesium oxide monohydrate group. Four people in the placebo group reported fatigue, headache, nausea, diarrhea and muscle twitching.
Quality of life
Quality of life improved in both groups. The magnesium oxide monohydrate group had larger improvements in two areas: role limits due to physical health and role limits due to emotional problems.
What the authors conclude
“MOMH was shown to be effective in the treatment of NLC as well as safe and well-tolerated.”
Also in their conclusions
- They conclude that MOMH was shown to be effective in the treatment of NLC as well as safe and well-tolerated.
- They say their results demonstrate the superiority of MOMH over placebo in treating NLC with respect to the number of NLC episodes, their duration and sleep quality.
- They state that the current study demonstrates that MOMH can provide a clinical solution to non-pregnant individuals who suffer from NLC.
How it was done
Magnesium supplements are widely used for night leg cramps, but the authors say there is little evidence that they work. They tested a form called magnesium oxide monohydrate, which had shown better uptake into cells in lab tests.
They ran a randomised, double-blind, placebo-controlled trial at 7 hospitals and outpatient clinics in Ukraine. 184 adults aged 45 and over with at least 4 night leg cramps during a 2-week screening period were assigned to take either 226 mg of magnesium oxide monohydrate or a placebo capsule once daily at bedtime for 60 days. 175 people completed the study.
What it can’t tell you
- The trial lasted 60 days, so it cannot show whether the effects last longer than that.
- The study did not track magnesium levels inside cells, so it cannot show a direct link between those levels and cramp improvement.
- Diet and physical activity were not monitored, so their impact on the results is unknown.
Who paid
- Conflicts
- Authors declare of having no conflict of interest.
- Authors work at
- Bogomolets National Medical University, Ukraine; Day Hospital Department, Ukraine; Clinical Hospital No.3, Ukraine
The paper
- Title
- A randomized, double-blind, placebo-controlled, multicenter study assessing the efficacy of magnesium oxide monohydrate in the treatment of nocturnal leg cramps
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Barna O, Lohoida P, Holovchenko Y, et al (2021). A randomized, double-blind, placebo-controlled, multicenter study assessing the efficacy of magnesium oxide monohydrate in the treatment of nocturnal leg cramps. Nutrition journal. doi:10.1186/s12937-021-00747-9Free full textPubMed 34719399DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error