Magnesium helps muscles and nerves work and is part of bone. Many people eat less than recommended, and deficiency is worth correcting. But there is little evidence that magnesium supplements relieve back pain or muscle tension in people who are not deficient. Food comes first, and supplements have a separate upper limit.
Check with a doctor or pharmacist if you take other medicines, have kidney disease, are pregnant, or are being treated for osteoporosis. Supplements interact with medicines and can be harmful in excess. See supplement safety.
How much you need
| Group | Recommended daily amount |
|---|---|
| Men 19 to 30 | 400 mg |
| Men 31 and over | 420 mg |
| Women 19 to 30 | 310 mg |
| Women 31 and over | 320 mg |
The upper limit for magnesium from supplements and medicines is 350 mg a day for adults; magnesium in food does not count toward it. Above that, supplements often cause diarrhoea and stomach upset.1
Food sources
Nuts and seeds, whole grains, beans and lentils, leafy greens, and dark chocolate. A varied diet with these foods usually covers the need.
Who may be low
People with digestive conditions that affect absorption, type 2 diabetes, long-term heavy alcohol use, older adults, and people on some medicines, such as long-term acid-reducing drugs or certain diuretics, are more likely to run low.1
Magnesium, bones and back pain
Magnesium is important for bone, but a 2026 review of bone supplements found the clinical evidence for magnesium supplementation limited and context dependent, unlike calcium and vitamin D in selected groups.2 For back pain itself there is no good trial evidence of benefit.
Correcting a magnesium deficiency is sensible. Taking magnesium to treat back pain or improve bones in people who are not deficient has little support.2
Practical advice
- Prioritise food sources.
- If you supplement, stay at or under 350 mg a day from supplements.1
- People with kidney disease should not take magnesium supplements without medical advice.
For what actually helps back pain, see what works for back pain.
Footnotes
General information, not medical advice. Every claim carries its source; where the evidence is thin, the page says so.Editorial policy · How we grade evidence · All sources · Disclaimer