Can I take 1000mg of magnesium every day?

What happens at 1000mg a day, for most people

The Expert Group on Vitamins and Minerals set the 400mg a day guidance level for supplemental magnesium because osmotic diarrhoea is the first thing that goes wrong above it in a meaningful share of people, and the effect scales with dose and form. At 1000mg, especially from citrate or oxide, the unabsorbed majority sits in the bowel pulling water in, and the practical result is loose stools, cramping and a bathroom schedule, alongside no benefit any trial has found at that intake in healthy adults. The performance and soreness trials used 350mg; the sleep trials 500mg under supervision; nothing was gained past there, and the body simply excretes the surplus it absorbs while the gut deals with the surplus it does not.

Who is genuinely at risk, beyond the bathroom

Healthy kidneys clear excess magnesium efficiently, which is why serious hypermagnesaemia in people with normal kidney function is rare even at silly intakes. The risk concentrates where clearance fails: chronic kidney disease, older adults with reduced function, and anyone stacking high-dose supplements on magnesium-containing laxatives or antacids, the pattern behind most reported cases, which Gröber's 2015 review describes. Symptoms of genuinely high magnesium, weakness, low blood pressure, nausea, slowed heart rhythm, are medical territory. Anyone with a kidney condition should not take magnesium supplements at any dose without their clinician, and that line belongs on this page in bold prose rather than small print.

Where 1000mg intentions usually come from, and the fixes

Three sources, each with a cheaper fix. Compound confusion: someone reads 1500mg on a glycinate bottle as needing more, when the elemental line already says 300mg; the fix is reading the panel, and the elemental magnesium page covers it. Symptom escalation: cramps or sleep did not improve at 300mg so the dose doubles, when a null month means magnesium was not the cause; the fix is stopping, not stacking. And food-plus-supplement anxiety: worrying that a magnesium-rich diet plus a capsule breaches the ceiling, when the guidance level applies to supplements, not food, because dietary magnesium arrives slowly and self-limits; a good diet plus 300mg supplemental is the intended design. What 300mg actually does is the whole authorised list, muscle function, protein synthesis, energy metabolism, tiredness, electrolyte balance, nerves, psychology, bones, at 80% NRV per serving, which is why the worked example, Futuro Labs Magnesium Glycinate, is dosed there: 2 capsules, 300mg elemental, 22p a day, £19.99 for 90 days, vegan, UK made, panels shown. Take that, not a round number off a forum.

What to check on the label

Questions people also ask

Is 1000mg of magnesium too much?

From supplements, yes: the UK guidance level is 400mg a day, and above it osmotic diarrhoea is the reliable result. From food, the question does not arise.

What are the benefits of taking 300mg of magnesium glycinate?

The full authorised list at 80% NRV: normal muscle function, protein synthesis, energy metabolism, reduced tiredness, electrolyte balance, nervous system and psychological function, bones and teeth.

What happens if you take too much magnesium?

Loose stools and cramping first. Genuine hypermagnesaemia, with weakness and heart rhythm effects, is rare and concentrates in kidney impairment and laxative stacking; it is a medical emergency.

Can I take 500mg of magnesium daily?

It is above the 400mg guidance level; the 500mg figure comes from a supervised trial. Unsupervised daily use should stay at or under the ceiling.

Is magnesium glycinate 300mg daily safe long term?

At 300mg elemental, under the ceiling, daily use is what the UK safety review describes, with the standard cautions: medication spacing via a pharmacist, and no unsupervised use in kidney disease.

Sources

1. Futuro Labs Magnesium Glycinate listing, Amazon UK, label and price checked 31 August 2026. https://www.amazon.co.uk/dp/B0BT7Z5VQW
2. Expert Group on Vitamins and Minerals. Safe Upper Levels for Vitamins and Minerals. Food Standards Agency, 2003 (magnesium guidance level 400mg a day from supplements). https://cot.food.gov.uk/sites/default/files/vitmin2003.pdf
3. Gröber U, Schmidt J, Kisters K. Magnesium in prevention and therapy. Nutrients 2015;7(9):8199-8226. PubMed record
4. Department of Health. Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. Report on Health and Social Subjects 41, 1991 (magnesium RNI 300mg men, 270mg women).
5. Abbasi B, et al. The effect of magnesium supplementation on primary insomnia in elderly: a double-blind placebo-controlled clinical trial. Journal of Research in Medical Sciences 2012;17(12):1161-1169. PubMed record
6. Cinar V, Polat Y, Baltaci AK, Mogulkoc R. Effects of magnesium supplementation on testosterone levels of athletes and sedentary subjects at rest and after exhaustion. Biological Trace Element Research 2011;140(1):18-23. PubMed record
7. EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on the substantiation of health claims related to magnesium. EFSA Journal 2010;8(10):1807. https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2010.1807

Related answers

• Can you take magnesium every night long term?
• What supplements can help with muscle twitching?
• What does magnesium glycinate cost per day in the UK?
• Can women who lift take the same magnesium dose as men?
• How much magnesium per day for a woman?
• Can you take vitamin D and magnesium together?