An underappreciated mineral for relaxation, recovery and older adults.
TL;DR: Magnesium supports muscle relaxation, nerve signalling and sleep regulation. Many UK adults, especially older adults, do not meet dietary intake recommendations. Supplementation may modestly improve sleep and cramps in people with low status, but it is not a longevity drug.
Magnesium is involved in over 300 enzymatic reactions, including ATP production, muscle contraction, nerve transmission, bone mineralisation and DNA repair. Blood levels tend to decline with age due to reduced dietary intake, lower gut absorption, increased urinary losses and common medications such as proton-pump inhibitors and diuretics.
For older adults, low magnesium is linked to:
The best UK dietary sources of magnesium include:
However, soil depletion, refined-food intake and appetite decline in older adults can make diet alone insufficient. A blood test (serum magnesium, or red-blood-cell magnesium for a better tissue estimate) can identify deficiency.
A 2022 systematic review and meta-analysis in BMC Complementary Medicine and Therapies found that magnesium supplementation improved sleep quality in older adults with insomnia, particularly when baseline magnesium status was low. Effects were modest and worked best alongside sleep-hygiene measures.
Proposed mechanisms include magnesium's role in GABA receptor function and melatonin regulation. Magnesium glycinate, bound to the calming amino acid glycine, is often preferred for evening use.
Evidence for magnesium preventing nocturnal leg cramps in older adults is mixed. A Cochrane review found that magnesium was not consistently better than placebo for older adults with idiopathic leg cramps, though it may help in pregnancy and in people with documented deficiency.
For muscle recovery and exercise-induced cramping, some trials show benefit, especially when sweat losses are high. For general age-related cramps, magnesium is worth trying if dietary intake is low, but expectations should be modest.
| Form | Typical use | Absorption / notes |
|---|---|---|
| Magnesium glycinate | Sleep, muscle relaxation, general | Well absorbed; gentle on gut; calming |
| Magnesium citrate | Constipation, general | Good absorption; osmotic laxative effect |
| Magnesium oxide | Constipation | Poor absorption; high elemental Mg |
| Magnesium threonate | Cognitive support | Preliminary brain-penetration claims |
| Magnesium chloride | Topical / oral | Variable skin absorption for topical use |
UK Nutrient Reference Values are 300 mg/day for men and 270 mg/day for women aged 19–64. Older adults may absorb less, so intake should be monitored. Supplemental elemental magnesium doses of 100–400 mg/day are common; going higher increases the risk of diarrhoea.
Cautions:
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These sources are referenced inline throughout the article and listed below for full transparency.
"The effect of magnesium supplementation on primary insomnia in older adults: a systematic review and meta-analysis."
View DOI"Magnesium for skeletal muscle cramps." Systematic review of magnesium for idiopathic and pregnancy-related cramps.
View DOI"Effect of oral magnesium supplementation on physical performance in healthy elderly women: a randomized controlled trial."
View DOI"Suboptimal magnesium status in the United States and elsewhere: are we missing the boat?" Reviews dietary intake, absorption and chronic-disease links.
View DOISome randomised trials show modest improvements in sleep quality and insomnia symptoms, particularly in people with low magnesium status. Effects are usually modest and not a replacement for good sleep hygiene.
Magnesium glycinate is often preferred for sleep and muscle relaxation because it is well absorbed and less likely to cause diarrhoea. Magnesium citrate and oxide are more commonly used for constipation. Magnesium threonate has been studied for brain penetration but evidence is preliminary.
The UK Nutrient Reference Value is 300 mg/day for men and 270 mg/day for women aged 19–64. Older adults may need similar amounts but absorb magnesium less efficiently. Supplemental doses of 100–400 mg/day elemental magnesium are common; higher doses increase diarrhoea risk.
Evidence is mixed. Magnesium appears to help cramps in people who are deficient, including during pregnancy, but routine magnesium supplementation has not consistently reduced nocturnal leg cramps in older adults.
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The content on this site is for informational purposes only and is not medical advice. Always consult a qualified healthcare professional before starting any supplement, especially if you are pregnant, nursing, taking medication or have a medical condition. People with kidney disease should only use magnesium supplements under medical supervision.