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Can Magnesium Relieve Muscle Cramps at Night?

Readers report that they can prevent most muscle cramps at night by taking magnesium supplements. Few scientists have studied this treatment.

Muscle cramps at night are sleep-stealers. They can wake you from a sound sleep with sudden horrifying pain and a tight spasm. Mostly, such nocturnal cramps afflict the calves, but some people report debilitating cramps in the feet or even the thighs.

Doctors used to think that such nighttime leg cramps were caused by electrolyte imbalances. As a result, they would suggest that patients eat more bananas (for potassium) or drink Gatorade or similar electrolyte-rich beverages.

More recently, though, scientists and health care providers have concluded that most cramps are due to nerve problems rather than electrolyte abnormalities (American Family Physician, Aug. 15, 2012). There is, however, a connection with iron deficiency. A nurse recently reminded us of this link.

Correcting Iron Deficiency Can Banish Muscle Cramps:

Q. I am a nurse working in gastroenterology. You have often written about muscle cramps. People with anemia often suffer from leg and foot cramps that resolve when the anemia is corrected.

A. Thank you for pointing out this connection. We also found documentation from medical research (PLOS One, Aug. 2, 2018). Compulsively eating ice is another seemingly unrelated condition that often disappears when anemia is treated (Blood Cells, Molecules & Diseases, July 2019). 

Occasionally, doctors may recommend supplements such as magnesium or vitamin B12, although there is not very much good research to support these treatments. Some readers report good results with magnesium supplements for muscle cramps.

Magnesium Supplements Prevent Muscle Cramps at Night:

Q. I take magnesium glycinate at bedtime and it completely relieves muscle cramps in my feet. I don’t get diarrhea when I stick with the glycinate form of magnesium.

A. Researchers have reported that leg cramps during pregnancy may respond to magnesium bisglycinate chelate supplements (300 mg per day) (Maternal & Child Nutrition, April 2015).  We don’t know if muscle cramps at night are different in pregnant women and other people, however.

A review of the medical literature concluded that it is unlikely that magnesium supplements prevent leg cramps in older people (Cochrane Database of Systematic Reviews, Sept. 12, 2012). A randomized controlled trial found that magnesium oxide supplements did not prevent muscle cramps at night (JAMA Internal Medicine, May 1, 2017).

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Readers Chime In:

Like you, though, other readers have found magnesium helpful.

Ellen noted:

“Constipation issues may be caused by a magnesium shortage. I take 200 mg of magnesium citrate and 500 mg Vitamin C at bed time. The magnesium also helps prevent leg cramps. My bowels work regularly every morning. I slowly adjusted the magnesium dosage until I found what works for me.”

 Janet has a complex regimen that includes magnesium:

“Benfiotiamine (B1, thiamine, but better absorption), magnesium glycinate, turmeric, 1 capsule before bed helps with muscle cramps at night. Hyland’s Muscle Cramps…just in case. I have to order benfotiamine online. This is what stopped mine.”

Ray is also a fan of magnesium to prevent muscle cramps:

“I was having regular nighttime leg & ankle cramps for years until I started taking magnesium glycinate, all because of places like this, not the doctor. Most of it started after my treatments for colon/rectal cancer which included chemo and radiation. Once I was past all that (2014 gone & hopefully for good) I’ve had cramps that make you cry at night and even some during the day. My hands during the day and legs during the night. Something had to change, so I searched till I found magnesium.

“I’m not saying it’s a cure-all but, I’m of the opinion that it’s better to preempt cramping rather than react to it. After all, who wants to be awakened with leg cramps that are next to ‘crippling’? After starting my magnesium glycinate regimen, I saw immediate relief. I couldn’t believe it but rather thought it was just a fluke. It’s now been over two months of using the MG and I’ve only had ONE bad cramp and that was last night. Usually, if any, they are so mild I can stand up and lay back down and everything is OK. To be fair, I worked my booty off yesterday in the yard.

Ray wondered if he might have other deficiencies:

“Also, I was so impressed that I made a doctor’s appointment to see if I was deficient in other vitamins or minerals. After the blood tests they informed me to keep on taking my (other) supplements and the magnesium. That’s all I got. No printout or anything else. My reason for thinking I was deficient was that I “empty” out EVERY DAY because of my cancer treatment damage. I would characterize it as mild diarrhea every day. I had to be losing vitamins and minerals but never gave it much thought before trying the magnesium.

“Needless to say, I’ll keep on researching this topic. I appreciate what I’ve read already on this site. It’s hard to argue with real results. Before, I was the guy that thought “I must not be drinking enough”, which btw was counter productive when you have prostate issues. Now, I’m the guy who knows more and feels better, and it’s not because of doctors.”

A Word of Warning:

People with poor kidney function must avoid magnesium supplements. Excess magnesium puts too much strain on struggling kidneys.

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About the Author
Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies..
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