Can magnesium supplements improve sleep, energy and concentration?

In the 1600s, England’s wealthy flocked to a well in Epsom Common that contained healing water. It had a bitter taste but a strong laxative effect that provided welcome relief from their rich, meat-heavy diet. “People who came there took a few glasses of the water mentioned – which tastes different from ordinary water – after which, walking up and down, it produced, in our opinion, a very good effect,” reported a happily uncorked visitor. It was later discovered that this was due to the water’s high content of magnesium sulfate, also known as Epsom salt.

Four hundred years later, the therapeutic properties of magnesium are once again praised and the press describes it as “the super mineral of the moment”. On social media, I’m bombarded with posts about the supposed benefits of taking magnesium supplements, including improved sleep, energy levels, mental clarity, bowel movements and heart health, as well as reductions in muscle pain, anxiety, migraines and PMS (premenstrual syndrome) symptoms. Oddly enough, these supplements come in many different forms. But do they actually work?

There is no doubt that magnesium is vital for our health. It stabilizes and facilitates the functioning of hundreds of enzymes that catalyze key chemical processes in the body. It also provides stability to fundamental molecules like DNA and ATP (adenosine triphosphate), binds to various receptors, and can enter and exit cells. This has led it to play a role in a wide range of crucial processes, including energy production in cells, nerve signaling, muscle contractions and regulation of heart rate.

Nutritionists generally advise trying to meet our magnesium needs by eating a mix of healthy foods rather than relying on supplements, as these foods contain additional minerals, vitamins, and other nutrients. Common sources of magnesium include nuts, seeds, leafy greens, whole grains, legumes, meat, seafood, dark chocolate, and beer (some beers are more bitter than others due to excess magnesium in the brewing water). People who get enough magnesium in their diet likely won’t benefit from taking a supplement because all of the magnesium positions in their body are already taken, meaning they’ll just eliminate the excess.

That said, it has become more difficult to get enough magnesium from food. We eat too much processed junk, which contains little magnesium. Additionally, over-exploitation of agriculture has depleted our soil of magnesium, so that even fresh fruits, vegetables and whole grains no longer contain as much as before. As a result, research suggests that around 35 to 50 percent of people in the UK, US and Australia do not get enough magnesium.

Some people are also at greater risk from low magnesium levels because they have conditions such as celiac disease or Crohn’s disease, which reduce its intestinal absorption, or diabetes or alcohol use disorders, which increase its excretion. When I was pregnant, I had excruciating leg cramps because pregnancy reduces magnesium levels, making it harder for muscles to relax after a contraction. Athletes also often have deficiencies, as intense, prolonged exercise increases the use of magnesium and also leads to its loss through sweating. Additionally, certain medications, including some immunosuppressants and chemotherapies, are known to deplete magnesium.

Unfortunately, there is no simple test to tell if you have a magnesium deficiency. About 99 percent of the magnesium in the body is stored in bones and soft tissues, meaning blood tests don’t give a clear picture of overall magnesium levels. The gold standard test involves a magnesium infusion followed by 24 hours of urine collection, which is expensive and impractical. If minimal magnesium is found in the urine, this indicates a deficiency because the body eagerly sucks up the magnesium from the infusion rather than eliminating it because it already has enough.

Symptoms of magnesium deficiency include muscle pain, fatigue, brain fog, irritability, and sleep problems, but of course, many other factors cause it as well. This makes it easy for magnesium supplement manufacturers to find customers.

The Many Types of Magnesium Supplements

Magnesium supplements come in many different forms because they contain magnesium salts, in which the positively charged magnesium must be paired with a negative ion, which can be chosen from a wide range of options. When magnesium is combined with the sulfate in Epsom salt, for example, it draws more water into the intestine to soften stools and keep things moving. Magnesium oxide and magnesium citrate work the same way. Other popular supplements combine magnesium with amino acids or other organic compounds that have questionable evidence of benefits for the brain, muscles, or heart. These include magnesium glycinate, L-threonate, malate and taurate. It should be noted, however, that in the case of the amino acids contained in these supplements, they can also be easily obtained from a healthy diet.

Another option is to apply magnesium lotions or sprays to the skin or soak in Epsom salt baths, but less magnesium is absorbed this way than when taken as an oral supplement. In fact, whether or not this product penetrates the skin is a matter of debate. This probably explains why applying magnesium cream to my legs during pregnancy didn’t seem to do much for my cramps. It’s also unclear whether the muscle relief offered by Epsom salt baths comes from the magnesium or just the warm water.

Personally, I don’t take magnesium supplements because I’m not convinced they offer anything more than a reasonable diet, and I like food more than pills. However, some evidence suggests that magnesium supplements may help with insomnia and mild anxiety in people who don’t get enough magnesium in their diet. Likewise, some evidence suggests they may reduce muscle soreness in athletes with higher magnesium requirements.

On the other hand, no decent research has been done on their effects on energy or concentration. However, if you find that they help in these areas, and even if it is just a placebo effect, there is no reason to stop taking them as they are considered relatively safe. Don’t overdo it, like the English lord Richard Evelyn, who died in 1670 after frequenting the waters of Epsom too much. According to his brother, the diarist John Evelyn, his disappearance was caused by “his excessive consumption of Epsom water when he was in perfect health and did not need it”.