Does magnesium help older adults sleep?

Possibly a little, but the evidence is thin. Magnesium takes part in nerve and muscle function, and low intake has been linked with poorer sleep in observational studies. Small trials in older adults have reported improvements in sleep measures, such as a 2012 double-blind trial in 46 older adults with insomnia using 500 mg of magnesium a day for eight weeks. Systematic reviews, however, rate the overall evidence as low quality. The Australian Institute of Sport places magnesium in Group C and, in people with adequate intake, there is no good evidence that extra magnesium improves sleep. Our rating is weak.

Who is more likely to benefit?

• People with low magnesium intake (few nuts, whole grains, legumes and green vegetables).
• People on diuretics or long-term acid-reducing medicines, which can lower magnesium; this needs a doctor's review and a blood test.
• Not people with normal intake, where the effect may be nil.

What dose and form?

Supplemental magnesium typically ranges from 100–350 mg elemental a day. The EFSA tolerable upper level for supplemental magnesium is 250 mg a day, set because larger amounts cause diarrhoea. The trial above used a dose twice that, which is a reason not to copy it. For sleep, many people take 100–200 mg with the evening meal.

What does it cost in South Africa?

Cost per 100 mg of elemental magnesium, from label amounts (October 2026, our calculation):

• The Real Thing Tri-Mag (about 120 mg elemental per capsule, 2 a day): about R2.64 per 100 mg at R285 for 90 capsules (Faithful to Nature). It also contains about 450 IU vitamin D3 per capsule, so count that in your total.
• Dis-Chem Gold Slow Release Magnesium (68.4 mg per tablet): about R3.29 per 100 mg at R134.99 for 60 (Dis-Chem Living Fit; the category page listed R169.99).
• Dis-Chem Gold Magnesium Chelate (99 mg per tablet): about R3.37 per 100 mg at R300 for 90.

See the full magnesium comparison and magnesium glycinate vs citrate.

What are the safety points?

Kidney function declines with age, and failing kidneys cannot clear magnesium, so supplements can build up. Avoid magnesium supplements with kidney disease unless prescribed. Separate doses by a few hours from levothyroxine, tetracycline or quinolone antibiotics and bisphosphonates. Stop if you get diarrhoea. See supplement-drug interactions for older adults.

What helps sleep more reliably?

Regular daylight and activity, a consistent bedtime, limiting caffeine and alcohol, and cognitive behavioural therapy for insomnia have stronger evidence. Read does magnesium help sleep and cramps for the general adult picture.

When should you see a doctor?

See a doctor for insomnia lasting over three months, loud snoring or breathing pauses (possible sleep apnoea), restless legs, low mood, or new confusion. This is general information, not personal medical advice.

Products mentioned