Magnesium

Adults need about 300mg (men) or 270mg (women) of magnesium a day, mostly met by diet.

By the Supplements UK editorial team. Last checked 9 October 2026. General information, not medical advice.

Short answer Adults need about 300mg (men) or 270mg (women) of magnesium a day, mostly met by diet. Magnesium contributes to a reduction of tiredness and fatigue and to normal muscle and nerve function. Evidence that it improves sleep is limited.

Magnesium and sleep

Small trials, mostly in older adults with low intakes, suggest a modest effect on sleep. There is no authorised claim for sleep. If poor sleep persists, see a GP.

Forms compared

Forms of magnesium
FormKnown for
Glycinate (bisglycinate)Gentle on the stomach
CitrateWell absorbed; can loosen stools
OxideCheap; poorly absorbed; laxative
L-threonateMarketed for the brain; little human evidence

How much is safe

Taking 400mg or less a day from supplements is unlikely to cause harm. More can cause diarrhoea. People with kidney disease should not take magnesium without medical advice.

A note on Oriflame

Oriflame's multivitamin contains some magnesium, but we found no stand-alone magnesium product in its UK range, so there is no product link here.

Keep exploring

Questions people ask

Does magnesium help you sleep?

Evidence is limited; it is not an authorised claim.

Which magnesium is best?

Glycinate and citrate are better absorbed than oxide.

Can I take this with medication?

Ask a pharmacist or GP first; some supplements interact with medicines.

Do supplements replace a balanced diet?

No. They are meant to add to a varied diet, not stand in for one.

Sources

Checked 9 October 2026.