How to take magnesium supplements

Updated April 17, 2017

Magnesium is essential for bone strength, immune function, heart rhythm stabilization and blood sugar regulation. The mineral is also involved in maintaining normal muscle and nerve function and in protein synthesis and energy metabolism. In 2006, the World Health Organization reached consensus that a majority of the world's population is magnesium deficient. Many have low body stores of the mineral due to inadequate dietary intake or kidney or digestive disorders. Magnesium supplements ensure sufficient intake and prevent and treat deficiency. Some magnesium supplements require a doctor's prescription, while others are available over the counter at most pharmacies

Ask your doctor for advice if you are currently taking digoxin, levomethadyl, quinine, antibiotics, blood pressure medications, diuretics or other prescription or over-the-counter medications. Magnesium supplements may interfere with the way some medications work in your body, according to the University of Maryland Medical Center, and your dose may require adjusting.

Stay away from magnesium supplements if you suffer from heart disease or kidney problems. Magnesium supplements may make these conditions worse.

Take magnesium supplements with meals to prevent diarrhoea, a common side effect of taking magnesium on an empty stomach.

Swallow extended-release tablets whole. Do not suck on them, crush them or chew them. Tablets are available that can be crushed and sprinkled on food for those who have trouble swallowing pills, but warns that this is not suitable for most magnesium supplements.

Mix powdered magnesium supplements with a full glass of water, stir well and then drink.

Follow the dosing guidelines on the supplement label carefully, or ask your doctor or pharmacist for advice. The usual dose of magnesium for teen and adult males is 270mg to 400mg each day. Adult and teen females require 280mg to 400mg per day.

Take a missed dose as soon as possible, but do not double up on doses. Because it takes time for your body to become deficient in magnesium, missing a few doses is not cause for concern.

Stop taking magnesium and consult your doctor if you develop fainting, dizziness, muscle paralysis, flushing or unexpected bleeding. These side effects are rare but they may indicate a serious reaction to the supplement.

Get medical attention immediately if you develop symptoms of magnesium overdose, such as blurred vision, severe drowsiness, slowed heart rate, breathing problems, decreased or increased urination, extreme dizziness, fainting or coma. Overdose is rare in healthy adults.

Store magnesium in a tightly closed container, away from moisture, heat and light, and at room temperature. Do not freeze magnesium supplements and discard expired supplements. Keep magnesium supplements out of the reach of children and animals.


Diarrhoea is a common side effect of magnesium supplements that generally disappears with continued treatment.

Magnesium supplements are available in powder, capsule, liquid, syrup, tablet and extended-release forms.


Early signs and symptoms of magnesium deficiency include nausea, vomiting, loss of appetite, weakness and fatigue. Severe deficiency may cause muscle cramps, seizures, numbness, tingling, abnormal heart rhythms and personality changes, notes the US-based Office of Dietary Supplements.

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