Can magnesium really help you sleep better – or just give you weird dreams?
Whether you're tossing and turning or waking up with leg cramps, magnesium might be your new bedside BFF – if it actually works.
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In the world of supplements, magnesium is hogging the spotlight for one very coveted but still-unproven benefit: Better sleep. Even if you haven’t seen it on social media (yet), your group chats may be buzzing with seemingly convincing anecdotes.
From the sleep-deprived executive (“My colleague swears by it.”) to the converted senior (“I don’t get leg cramps now, which used to wake me up.”) to the confused millennial (“I don’t know why but I get weird dreams and nightmares when I take magnesium.”), this essential mineral has caught the wellness wave and is surfing its way into many people’s medicine cabinets.
“Overall, there is a noticeable rise in the use of supplements, including magnesium, over the past few years,” said Rachel Wong, a dietitian from National University Hospital’s Department of Dietetics.
The Pharmaceutical Society of Singapore (PSS) has also “noticed an increase in demand of magnesium supplements in recent years”, said its spokesperson, primarily for sleep support and managing muscle cramps. “There has been notable interest in magnesium glycinate specifically as patients seek natural sleep aids.”
But does magnesium really help? And with so many magnesium forms out there, which one should you take? We find out.
WHAT IS MAGNESIUM NEEDED FOR?
Magnesium is an important mineral, said Wong, that has more than 300 functions in the body’s cardiovascular, nervous, muscular and skeletal systems. “The main role of magnesium is its involvement in the metabolism of food (fats, protein and carbohydrates), muscle contraction and bone development,” she said.
PSS added that it builds protein in your body as well as controls your blood glucose and blood pressure.
HOW DOES IT HELP WITH SLEEP? AND WHAT ABOUT WEIRD DREAMS?
Experts haven’t quite pinpointed how magnesium helps with sleep, according to Sleep Foundation, but studies of older adults have found that magnesium “helped with falling asleep faster and protected against waking up earlier than intended”.
Even so, Wong noted that “there is mixed and weak scientific evidence behind the relationship between magnesium and sleep”. “Most of the randomised control trials have small sample size, short study duration and reliance on self-reported data which poses bias.”
As for the weird dreams, Wong has a theory: “Magnesium plays a role in the regulation of neurotransmitters, such as the production of gamma-aminobutyric acid (GABA), which is a chemical messenger that serves as the primary inhibitory neurotransmitter to reduce neuronal activity. GABA can promote deeper sleep, that is, REM sleep.”
And because most dreams occur in this stage of sleep, Wong said, “the increased frequency of dreams, which may be vivid or intense, may then be more easily remembered by the individual”. “However, most evidence linking magnesium and nightmares is not strong as they are commonly anecdotal.”
HOW DOES MAGNESIUM HELP WITH RESTLESS LEG SYNDROME AND MUSCLE CRAMPS?
First, some context: Calcium isn’t only used by your body to maintain bone health; it also activates your nerves and causes muscle contractions. It’s all good when you’re exercising or getting about your day; bad when you’re trying to sleep but your leg muscles won’t stop contracting.
Enter magnesium. It helps with “calcium channel regulation and muscle physiology”, which in turn, said PSS, minimises recurrent leg cramps and restless leg syndrome. The mineral does that by blocking calcium from reaching and activating the nerves that contract the muscles. The result: No more nerve-y sensation and muscle cramps when you’re trying to sleep.
HOW DO YOU TELL WHETHER YOU’RE DEFICIENT OR NOT?
“Most people can get enough magnesium from their diet,” said PSS, otherwise you’d notice symptoms of deficiency such as “a loss of appetite, nausea, vomiting, extreme tiredness and weakness”.
A severe lack of magnesium “may result in numbness, tingling, muscle cramps, seizures or an abnormal heartbeat”, according to PSS. “However, these signs and symptoms are not unique to magnesium deficiency and may be caused by other health conditions."
“Some people may benefit more from magnesium supplements if they already have a deficiency, which might improve sleep quality,” Wong explained. “Others who already have sufficient magnesium levels may not feel any difference."
Have yourself assessed by a doctor if you think you’re deficient, said PSS, and also have type 2 diabetes or a gastrointestinal disease such as Crohn’s disease; consume significant amounts of alcohol; or on medications such as proton pump inhibitors and diuretics.
Magnesium levels can be measured using a blood test, said Wong. “Most patients who are magnesium-deficient are often malnourished or suffer from conditions resulting in excessive losses or poor absorption via the gastrointestinal system.”
HOW MUCH MAGNESIUM DO YOU NEED?
“There is no locally specific recommended dietary allowance (RDA) for magnesium,” said Wong. Referencing the US Institute of Medicine, she recommended 310mg for women and 400mg for men per day for those aged 19 to 30. For those aged 31 years old and above, aim for 320mg for women and 420mg for men daily, she said.
WHAT FORM OF MAGNESIUM DO YOU NEED?
Here’s a checklist on how to choose the right type for your needs:
Magnesium glycinate: This is likely the magnesium form found in "sleep better" supplements. It may have calming properties and help with anxiety and stress.
Magnesium citrate: It is used to treat occasional constipation for no more than a week, and also commonly used to empty the colon before a colonoscopy.
Magnesium oxide: It is more frequently used to manage digestive issues such as heartburn, indigestion and constipation (it has a laxative effect).
Magnesium sulphate: Commonly known as Epsom salt, it's often used to soothe sore muscles in foot soaks and baths. It can also be prescribed as a pre-colonoscopy prep.
Magnesium chloride: It's well absorbed and suitable for a magnesium deficiency or electrolyte imbalance.
Magnesium taurate: Adequate levels of magnesium and taurine may help to regulate blood sugar levels and blood pressure but more studies are needed to substantiate the claims.
Magnesium L-threonate: Increasing magnesium levels in brain cells is thought (but yet to be proven) to help with depression, Alzheimer's disease and age-related memory loss.
Very likely, you’re already getting your magnesium covered through foods such as pumpkin seeds, chia seeds, spinach, almonds, peanut butter, banana and brown rice, said Wong. Moreover, too much of a good thing is bad, including magnesium. Limit it to 350mg from supplements daily, said Wong, as there may be adverse effects if consumed in high doses.
These adverse effects, said PSS, include diarrhoea, nausea and abdominal cramps. “The symptoms are more frequently associated with specific forms of magnesium, such as magnesium carbonate, magnesium chloride, magnesium gluconate and magnesium oxide.
“Consuming excessive amounts of magnesium (greater than 5,000 mg per day) can result in toxicity,” continued PSS. “Potential symptoms include low blood pressure, lethargy, muscle weakness, difficulty breathing, irregular heartbeat, and in severe cases, cardiac arrest.”
WHAT SHOULD YOU TAKE NOTE OF WHEN SUPPLEMENTING?
It’s prudent for you to check with your doctor before supplementing, especially if you have a pre-existing condition such as kidney problems. “This is because your kidneys may not be able to remove the extra magnesium properly, which increases the risk of magnesium buildup or toxicity in the body,” cautioned PSS.
Put on certain medications by your doctor? "It is advisable to take magnesium supplements at least two hours apart to prevent interference with the effectiveness of the medications," advised PSS.
Medications that can potentially interact with magnesium include oral bisphosphonates for osteoporosis (alendronate and risedronate) and certain antibiotics such as doxycycline, ciprofloxacin and levofloxacin.
