Calcium and Magnesium for Leg Cramps

There are health supplements on the market that combine magnesium and calcium into one tablet, which, according to manufacturers, will alleviate muscle aches and prevent muscle cramps. While it's true that most people don't get enough magnesium in their diet, the University of Maryland Medical Center says it's very unusual for a person to be "truly deficient" in magnesium, and medical opinion is divided over whether magnesium and calcium provide relief for leg cramps.

Identification: Leg Cramps

Leg cramps are the sudden contraction of a muscle—usually in the calf—that causes excruciating, momentary pain. They often result from wearing poorly design shoes, exercise or dehydration. According to the Harvard Medical School, leg cramps can also be caused by drinking too much water and diluting the concentration of sodium in your blood. Leg cramps often come on at night, likely because tight-fitting sheets can keep your toes pointed, prompting your calves to contract.

Does Magnesium Calcium Help?

Companies that sell magnesium calcium supplements claim leg cramps are a sign of magnesium deficiency. They sell 500 mg supplements that provide more than the recommended daily allowance—400 mg—in a slow-release form that the manufacturers say doesn't cause diarrhea, a common side effect of magnesium supplements. No clinical studies are cited with many of these supplements.

How the Body Uses Magnesium

While the supplement makers' claims may not be scientifically proven, health experts acknowledge that magnesium is a key mineral for the human body. According to the University of Maryland Medical Center, every organ in the body, as well as your muscles, bones and teeth, needs magnesium. It activates enzymes, helps produce energy and regulates levels of copper, zinc, potassium, vitamin D and calcium.

Magnesium Deficiencies

According to the University of Maryland, magnesium deficiencies can cause agitation and anxiety, insomnia, nausea of vomiting, leg spasms and restless leg syndrome. Those with a magnesium deficiency may notice poor nail grown, low blood pressure and abnormal heart rhythms as well. Magnesium-rich foods include whole grains, nuts and green, leafy vegetables.

Expert Insight

According to the University of Missouri, magnesium has never been clinically proven to prevent leg cramps, although it's "often thought" to help. Calcium supplements have also often been considered helpful in treating leg cramps, says the University of Missouri. The University of Maryland Medical Center recommends you check with your health care provider before taking any magnesium supplement, however, and that you check with your pediatrician before giving it to a child.


Harvard Medical School recommends taking quinine tablets for leg cramps because it seems to discourage nerve "excitability." Although quinine is not available as an over-the-counter drug anymore, it can be purchased as a food supplement. The Louisville Medical School offers different advice, recommending those with leg cramps take zinc, magnesium and calcium supplements rather than quinine.