How much magnesium should you take per day?
Adults need about 310 to 320 mg (women) or 400 to 420 mg (men) of magnesium a day from all sources, mostly food. Supplements typically add 100 to 350 mg of elemental magnesium. The US upper limit for supplemental magnesium is 350 mg a day and EFSA's is 250 mg. People with kidney disease should not supplement without medical advice.
- NIH magnesium RDA: 400 to 420 mg a day for men and 310 to 320 mg for women, all sources.
- Upper limit for supplemental magnesium: 250 mg a day (EFSA) or 350 mg a day (NIH).
- Dis-Chem Gold Magnesium Chelate gives 99 mg elemental magnesium per tablet (R299.99 for 90, October 2026).
- The AIS lists magnesium in Group C (not advocated for athletes without a clinical reason).
How much magnesium do adults need?
The NIH recommended dietary allowance (RDA), counting food and supplements together:
| Age | Men | Women |
|---|---|---|
| 19 to 30 | 400 mg | 310 mg |
| 31 and over | 420 mg | 320 mg |
Good food sources are nuts, seeds, legumes, whole grains and leafy greens. Most people closing a gap need a supplement of well under the full RDA.
How much should a supplement provide?
Typical supplemental doses are 100 to 350 mg of elemental magnesium a day. Elemental magnesium is the magnesium itself, not the weight of the compound it is bound to. Two upper limits apply to supplemental magnesium (not food):
- EFSA: 250 mg a day, set because of its laxative effect.
- NIH / US: 350 mg a day for adults.
Stay at or below the lower figure unless a doctor directs otherwise. Doses above these limits mainly cause diarrhoea, nausea and cramping; very high doses can cause low blood pressure and irregular heartbeat.
What does that look like with South African products?
Using label amounts as of October 2026:
| Product | Elemental Mg | Label dose | Daily elemental Mg |
|---|---|---|---|
| Dis-Chem Gold Slow Release Magnesium | 68.4 mg per tablet | 2 to 3 tablets | 137 to 205 mg |
| Dis-Chem Gold Magnesium Chelate | 99 mg per tablet | 1 to 2 tablets | 99 to 198 mg |
| The Real Thing Tri-Mag | about 120 mg per capsule | 2 capsules | about 240 mg |
| Flora Force Magnesium Glycinate | 100 mg per capsule (our reading of the label) | 1 to 2 capsules | 100 to 200 mg |
Tri-Mag's two-capsule dose is just under EFSA's limit, so avoid adding another magnesium product on top. See best magnesium in South Africa for price per 100 mg.
When is the best time to take it?
With food, to limit stomach upset. Evening dosing is common for preference; it is not proven to be better. Split larger doses across the day if your gut is sensitive.
Does it help with sleep or cramps?
In people with adequate intake, there is no good evidence that extra magnesium improves performance, sleep or exercise cramps, and the AIS places it in Group C. Supplements help when intake is low or a deficiency has been diagnosed. For the evidence in detail, see does magnesium help sleep and cramps? and for form differences magnesium glycinate vs citrate.
Who should be careful?
- Kidney disease: magnesium is cleared by the kidneys, and it can build to dangerous levels in kidney failure.
- Certain medicines: keep magnesium a few hours apart from tetracycline and quinolone antibiotics and from bisphosphonates.
- Pregnancy, breastfeeding and under-18s: ask your doctor or dietitian before using supplements.
If you want to know whether you actually are low, a blood test is the starting point, though blood levels are an imperfect guide to body stores. Read also can you take too many vitamins?. Pricing and form comparisons are on our best magnesium page.
Products mentioned, with dated prices
| Product | Size | Price | Servings | R per serving | Sweeteners |
|---|---|---|---|---|---|
| Dis-Chem Gold Slow Release Magnesium 60 coated tablets | 60 tablets | R134.99-R169.99Dis-Chem Living Fit, Oct 2026 | 24 | R5.62 | not stated |
| Dis-Chem Gold Magnesium Chelate 90 coated tablets | 90 tablets | R300Dis-Chem Living Fit, Oct 2026 | 60 | R5.00 | not stated |
| The Real Thing Tri-Mag 90 capsules | 90 capsules | R285Faithful to Nature, Oct 2026 | 45 | R6.33 | not stated |
| Flora Force Magnesium Glycinate 60 capsules | 60 capsules | R169Faithful to Nature, Oct 2026 | 30 | R5.63 | not stated |
Compare the options
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Related questions
- What is the best magnesium supplement in South Africa?
- Does magnesium help sleep and muscle cramps?
- Magnesium glycinate vs citrate: which is better in South Africa?
- Does magnesium help older adults sleep?
- Can you overdose on vitamins and minerals?
Sources
- NIH Office of Dietary Supplements: Magnesium, health professional fact sheet
- EFSA: Overview of tolerable upper intake levels (summary report, 2024)
- Australian Institute of Sport Supplement Framework, Group C
Educational information only, not medical advice. Speak to a doctor, pharmacist or registered dietitian before using supplements if you are pregnant or breastfeeding, under 18, taking medication, or living with kidney, liver or heart disease.
Cite this page: Healthnews24, “How much magnesium should you take per day?”, updated 27 October 2026, https://www.healthnews24.co.za/answers/how-much-magnesium-per-day/. Plain-text version: /answers/how-much-magnesium-per-day.md