Magnesium for sleep: which form? The bigger question is whether it works
- Claim
- MAGNESIUM FOR SLEEP?
- Catch
- LOW-QUALITY EVIDENCE
- Verdict
- FORMS ASIDE, PROOF IS THIN
Magnesium oxide, the cheapest form, is poorly absorbed: in a study of four commercial preparations, its fractional absorption was about 4%, lower than magnesium chloride, lactate or aspartate. At higher doses magnesium oxide is used as a laxative. Forms like glycinate and threonate are marketed as calming or brain-friendly, but head-to-head trials comparing forms for sleep are scarce. On the bigger question, a 2021 systematic review and meta-analysis found 3 randomized trials of oral magnesium for insomnia in 151 older adults. Magnesium shortened the time to fall asleep by about 17 minutes versus placebo, but the change in total sleep time was not statistically significant, and the evidence was rated low to very low quality. The catch: these were small trials in older adults only. People with kidney disease should not take magnesium supplements without medical advice.
SOURCES
- Mah & Pitre (2021), "Oral magnesium supplementation for insomnia in older adults: a systematic review & meta-analysis," BMC Complementary Medicine and Therapies
- Firoz & Graber (2001), "Bioavailability of US commercial magnesium preparations," Magnesium Research
- NIH Office of Dietary Supplements, Magnesium fact sheet for health professionals
For information only, not medical advice. Talk to your doctor before taking supplements, especially if you have kidney problems or take other medicines.
