The Canadian researchers behind this paper noted that more, better-quality research is needed to confirm this finding. “The evidence is not conclusive at present,” says Dr Ali. “More research and studies are needed, and published reviews have not come strongly in support or against their use.”
Alleviating restless leg syndrome (RLS)
Restless leg syndrome refers to the overwhelming urge to move your legs. Symptoms, which can include a crawling or creeping sensation in the feet, calves and thighs, are often worse at night, making it difficult to sleep.
Some research suggests that magnesium supplements may help. One small study, which recruited a dozen adults with the condition to take 200mg of magnesium daily for two months, found that their symptoms improved.
It’s thought that this may be down to magnesium being a natural calcium-blocker, as calcium causes muscles to contract. However, larger studies are needed to confirm this finding.
Reducing insomnia symptoms
While the occasional bad night’s sleep is normal, it can tip into insomnia if you regularly find it difficult to get to sleep, wake up several times during the night or wake up early and can’t get back to sleep.
One study found that magnesium could ease insomnia symptoms. Researchers in Iran recruited 46 people in their 60s who completed a quiz on their symptoms and were either given the supplement or a placebo pill for eight weeks. Results show that those who took magnesium daily ended up suffering from less severe insomnia.
A separate review from a team at Columbia University, which included around 150 patients, found that those who took the supplement found it easier to get to sleep.
“If you are struggling to get enough from your diet then a daily magnesium supplement of 400mg or less is recommended,” says Pennington. A higher dose is not better, as too much can lead to diarrhoea and other side effects, she notes, including vomiting, or in extreme and rare cases, muscle weakness, respiratory disease or cardiac arrest.
As well as checking the magnesium content of the food you’re eating, there are warning signs that you’re not getting enough magnesium – nausea, weakness, twitching, cramping or an irregular heartbeat are some, as well as sleeping problems, Pennington says.
If you’re experiencing these symptoms, you should see a GP or specialist, Dr Ali says. They can refer you for tests, make a diagnosis and recommend treatments, he notes.
“If someone is experiencing symptoms and they want to try magnesium supplements to assess the benefit, they can,” he says. “However, we would encourage them to get in touch with their GP and seek guidance and appropriate help.”
Magnesium is most commonly available in supplement form as tablets, liquid or lotion formulas, says Pennington.
Check the packaging for instructions but, typically, one or two magnesium tablets are advised per day to be consumed with your main meal or plenty of water.
If taking the supplement in liquid form, 20ml is usually advised per day before a meal. When it comes to lotion, 5ml daily is usually recommended for the skin near to bedtime.
There are also different magnesium ingredients. Magnesium citrate (magnesium that has been combined with citric acid) and magnesium glycinate (formed from magnesium and glycine) are more easily absorbed by the body, while magnesium oxide (magnesium with salt and oxygen) isn’t absorbed as well. All types are widely found in pharmacies and health stores.