Should You Take Calcium Supplements for Leg Cramps?

Many people complain that they are often awakened by severe nighttime leg cramps. They may have tender muscles in the morning as a consequence, but the biggest problem is the pain along with the sleep disruption. Doctors once prescribed quinine to prevent this occurrence, but that is no longer an option. (Some recommend tonic water instead, however.) One reader discovered, with her doctor’s help, that she did well on calcium supplements for leg cramps. Will you?

Trying Calcium Supplements for Leg Cramps:

Q. I suffered for seven years from really bad nighttime leg cramps. The numerous doctors I saw told me everything from “I don’t know” to “you’re getting old.”

Then my gynecologist told me a calcium deficiency could cause cramps and prescribed an over-the-counter calcium supplement. He said it would probably take about a week to notice relief. He was right! I still take calcium supplements after 30 years and have no trouble with leg cramps.

A. We have heard from hundreds of leg cramp sufferers about their remedies. Some people, like you, report success with minerals. They take magnesium, iron or calcium supplements for leg cramps. Others get no relief from such pills.

On the other hand, there is a wide range of remedies that people have found successful. What works for one person may not work for somebody else.

Most people report, however, that swallowing a spoonful of yellow mustard is surprisingly effective. Others insist that a sip of pickle juice works just as well. Trial and error seems to be the best way to learn what helps a given individual most.

Causes of Muscle Cramps:

Until about two decades ago, most experts attributed exercise-induced muscle cramps to dehydration or electrolyte imbalance (Journal of Sports Sciences, June 1997). Most likely they assumed that nighttime leg cramps had similar causes. Then, studies indicated that overexcited motor neurons resulted in the spasms we calll muscle cramps. The latest research suggests that this excitability originates in spinal neurons (Journal of Electromyography and Kinesiology, Aug. 2018). Unfortunately, although scientists are closer to understanding the causes of muscle cramps, they still haven’t come up with a sure-fire way to relieve them that will work for everyone.

Vitamin K Supplements Star in RCT for Leg Cramps:

In a recent study of nearly 200 older people afflicted with leg cramps, vitamin K2 did very well (JAMA Internal Medicine, Dec. 2024). Investigators assigned the volunteers to take 180 micrograms of vitamin K2 (MK-7) or an identical-appearing placebo pill every night for eight weeks. Participants kept records of their nocturnal leg cramps. Those in the vitamin K2 group reported significantly fewer leg cramps–less than one a week overall–than those in the placebo group. The average for placebo participants was 3.63 per week.

Even better, the performance of vitamin K2 improved over the course of the study. By the last week, people in the K2 group averaged fewer than 1/2 cramp per week. They also reported that their cramps were less severe and did not last as long.

So far as we are aware, vitamin K2 at such a dose is safe. We don’t know why this would work and we really look forward to scientists digging into the explanation. You can find a fascinating summary of this study, complete with a lovely graph, at Examine.com.