Evidence grade: C
Magnesium is vital for muscle and nerve function. Performance benefits show up mostly in people who are deficient. Sleep and cramp claims rest on limited data.
What it is
A mineral involved in hundreds of enzyme reactions, including energy production and muscle contraction. It is found in greens, nuts, seeds, legumes and whole grains.
What people claim
- Better sleep
- Fewer muscle cramps
- Better performance and recovery
Doses used in studies
Adult recommended intakes are about 310–420 mg a day from all sources. The upper limit for supplements alone is 350 mg a day.
These are amounts researchers tested, not a recommendation for you.
Who should be cautious
- People with kidney disease
- High doses, especially oxide and citrate forms, can cause diarrhea
- It can interfere with some antibiotics and osteoporosis drugs; space doses apart
- Pregnant or nursing people: ask a doctor first, as safety data is limited
- Anyone taking prescription medication: check with a doctor or pharmacist for interactions
- Under 18: talk to a doctor or parent before using any supplement
Sources
- Can magnesium enhance exercise performance? Zhang et al., Nutrients, 2017
- Magnesium fact sheet for health professionals NIH Office of Dietary Supplements
← All supplements · Laws & Research
Education only, not medical advice. Supplements are not reviewed by the FDA for safety or effectiveness before sale, and nothing here is meant to diagnose, treat, cure or prevent any condition. Talk to your doctor or pharmacist before starting any supplement, especially if you are pregnant, nursing, take medication or have a health condition.