Magnesium
Magnesium (Mg)
Minerals. Modern nutrition.
Also called Magnesium citrate, Magnesium glycinate, Magnesium oxide, Epsom salt (magnesium sulfate)
Pinyin: měi
Spanish: Magnesio
Diarrhea; risky with kidney diseaseA mineral the body uses in more than 300 enzyme reactions, including those for muscle, nerve, heart rhythm and blood sugar control.
Did you know? About half of the body's magnesium sits in bone, and only about 1 percent is in the blood. That is why a normal blood test does not always rule out low magnesium.
What it may help, and how strong the proof is
- Constipation. Magnesium citrate and magnesium oxide draw water into the bowel and are common laxatives. They work for occasional constipation. Daily long-term use should be checked with a doctor.Good proof
- Sleep. Small trials in older adults found better sleep quality with magnesium. The trials were small and short, so the proof is weak.Early proof
- Heart health. Low magnesium is linked to heart rhythm problems, and doctors give magnesium by IV for some dangerous rhythms. Magnesium pills have not been shown to prevent heart attacks.Early proof
- Muscles & exercise. Magnesium is often sold for muscle cramps. Reviews of trials in older adults found it did not reduce leg cramps. Extra pills have not been shown to help cramps in most people.Not supported
Parts of the body
Traditional use
Epsom salt baths, named for the town of Epsom in England, have been used for sore muscles and skin since the 1600s. Nuts, beans and whole grains, all rich in magnesium, have long been staples in many diets.
How it is classified
- Herbal actions
- Nutritive, Antispasmodic, Laxative. Energy: neutral.
How people take it
Adults need 310 to 320 mg a day (women) or 400 to 420 mg a day (men), depending on age (RDA). The upper limit is 350 mg a day from supplements and medicines. Food magnesium has no upper limit, because the body controls how much it absorbs from food.
Food, capsule, tablet, powder and bath.
Where to get it
Good sources are pumpkin seeds, chia seeds, almonds, cashews, peanuts, spinach, black beans, edamame, quinoa, brown rice, avocado, and dark chocolate. Pills come as magnesium citrate, glycinate, oxide and chloride. Epsom salt (magnesium sulfate) is used for baths and laxatives.
Be careful
Magnesium from food is safe. Pills often cause diarrhea, and very high doses can cause low blood pressure, irregular heartbeat and confusion. Kidney disease makes it hard to clear magnesium, so people with kidney disease should ask a doctor first.
Avoid if: kidney disease; myasthenia gravis.
Mixing with other things
- Works well together
Often part of migraine prevention plans. The combination is not well studied.
- Works well together
The body needs magnesium to turn vitamin D into its active form.
- Works well together
Calcium and magnesium work as partners in muscle and bone, so their balance matters.
- Works well together
Low magnesium makes low potassium harder to correct, so the two are often checked together.
- Works well together
Often sold with magnesium and vitamin D in bone blends.
- Use cautionAntibiotics (doxycycline, Cipro and similar)
Magnesium binds quinolone and tetracycline antibiotics in the gut and cuts their absorption. Take them 2 to 4 hours apart.
- Worth knowingWater pills (furosemide, hydrochlorothiazide)
Some water pills make the body lose magnesium, so a doctor may check levels.
- Worth knowingBlood pressure medicine (lisinopril, amlodipine, losartan)
Magnesium can lower blood pressure slightly, which may add to blood pressure medicines.
The honest take
Magnesium is needed for hundreds of body reactions, and many people do not get enough. Pills help some people, especially for constipation. Claims for sleep, cramps, anxiety and blood pressure are weaker than the marketing suggests, and a blood test does not show total body stores.