If you’ve been on social media recently, you’ve likely seen people touting the benefits of magnesium (and the different types of magnesium). Influencers ― and even some doctors ― on social media platforms claim it can improve almost everything, from constipation to sleep to brain fog.
But experts say it’s tough to know if these claims are actually true.
“With supplements, in general, there’s not a lot of requirements out there for good hard research,” said Jesse Wisniewski, a clinical pharmacist at Cedars-Sinai Medical Center in California. “The studies that have been done, there are usually a lot of flaws in those studies, so it’s unclear how to apply it to certain groups of patients.”
That said, the nutrient does play a role in our overall health. “Magnesium is a mineral element, so it’s an essential part of helping our body function normally,” Wisniewski said. It’s essential for nerve, muscle and heart function, he added. It’s also important for maintaining bone health.
According to Perri Halperin, a clinical nutrition coordinator at Mount Sinai Health System in New York, the recommended daily magnesium intake for adult men is between 400 and 420 milligrams of magnesium per day. For women, that number is a little lower — between 310 and 320 milligrams per day.
Wisniewski said in a Western diet, roughly two-thirds of people are not getting enough magnesium. And according to the Cleveland Clinic, many people with a magnesium deficiency have no symptoms at all, or very mild symptoms, so you are probably unaware if you fall into this category. (For some, though, low magnesium levels may present as nausea and fatigue.)
There’s virtually no risk of over-consuming magnesium when you’re getting it through food, Halperin said. Plus, extra magnesium from food is pretty easily filtered out by your kidneys unless you have kidney issues, she noted.
This is not the case for supplementation, though — which can cause adverse effects like diarrhoea and low blood pressure in those who have too much magnesium. “[It’s] hard to reach the levels of magnesium that cause toxicity through diet alone, but much easier when you’re popping a pill,” Halperin explained.
“It’s always a good idea to let your doctor know what supplements you’re taking.”
- Jesse Wisniewski, clinical pharmacist at Cedars-Sinai Medical Center
What’s more, when comparing magnesium-rich food and magnesium supplements, the magnesium our bodies get through food has been highly studied; research shows it helps with the necessary functions mentioned above. However, magnesium as a supplement ― and any potential benefits that come from it ― is far less studied, Halperin explained.
All that said, the supplements still exist on the market for a reason ― and it’s hard to ignore the glowing testimonials many have posted about magnesium pills. Not to mention the fact that there are multiple options out there, including magnesium glycinate, magnesium citrate and magnesium L-threonate (and that’s not even all of them).
Do all of those work for the same problems? What’s the difference? Do we even need it? We asked experts to find out:
A magnesium supplement is good for constipation.
“I would say the best-researched use of magnesium that we have a lot of good data on is for constipation,” said Gina Milano, a clinical dietitian at Stanford Health Care in California. “And so there’s various forms of magnesium that are used to help alleviate constipation.”
One form is magnesium oxide, which Milano said is inexpensive and easy to find at your local grocery store. Magnesium oxide is not well absorbed by the body, Milano said, so even if you are taking large doses of it, your body isn’t actually soaking much of it up. “However, it’s helpful for promoting and alleviating constipation,” Milano added.
Magnesium hydroxide is also good for constipation, she said. You may have heard it referred to as milk of magnesia, which is readily available at stores as well. Magnesium citrate is good for constipation as well, she said.
There’s some evidence that magnesium can also help with migraines.
According to Halperin, magnesium can be helpful for migraine pain as well. “Studies have shown low magnesium levels in people suffering from migraines,” she said.
“In fact, the National Headache Foundation suggests a daily dose of 400 to 600 milligrams of magnesium to reduce the frequency of migraine attacks,” Halperin noted. Specifically, magnesium oxide is best for migraine treatment, according to the American Migraine Foundation.
It’s worth knowing that the suggested dosage for migraine treatment might be higher than the recommended daily intake for men and especially women. “So, there’s the possibility of side effects like diarrhea, muscle weakness if you’re taking magnesium supplements at that level,” Halperin said.
There is also some evidence that it can help with memory and cognition — but more research is needed.
Social media influencers claim magnesium helped them with the brain fog that can occur as a result of a COVID infection. But experts say that isn’t a definite use for the supplement — though there is some promising evidence that needs more backing.
“More recently there’s been much more research about magnesium L-threonate and that’s been linked to improved cognition and memory and even learning,” Milano said, noting that this type of magnesium is “able to cross the blood-brain barriers,” making it highly absorbable by the body.
A 2010 study looked at the use of this kind of magnesium in rats and found that both young and elderly rats experienced improved memory and learning, Milano said. There was also a small 2022 study in humans that found magnesium L-threonate, coupled with vitamins and minerals including vitamins C and D, positively affected cognition as well. But it’s unclear if it was the magnesium itself or the other items used in tandem, Milano noted.
Additional testing is needed to determine just how effective magnesium is for memory and cognition. And Milano said you should be wary of brands touting the benefits of magnesium L-threonate before more research is conducted.
“I think the thought here is, ‘Oh, maybe this can be only used on a daily basis, but maybe it also could be used in prevention and treatment for elderly adults who are struggling with cognition’ … that’s looking a little bit more promising,” Milano said.
The data on magnesium’s effect on sleep is mixed.
There is some evidence behind using magnesium for better sleep, Wisniewski said. “Sleep ... that is definitely one of the common ones that people are using it for, and there’s some limited evidence about it,” he said.
The studies on this have largely looked at older adults, but suggest magnesium can help people fall asleep faster, though it did not increase the amount of time they were actually asleep, Wisniewski explained. That said, the strongest evidence is from short-term studies (so the effects and risks long-term are unknown), and the favourable results could have been by chance, Wisniewski added.
“Magnesium assists with neurological pathways, and when they’re not functioning appropriately due to low levels, it can lead to mood disorders [and] sleep disorders ― but it’s not well understood.”
- Perri Halperin, clinical nutrition coordinator at Mount Sinai Health System
Halperin and Milano both added that more research is needed before magnesium can be considered a science-backed sleep aid. Milano also said that many studies don’t explicitly state the type of magnesium used for better sleep.
If you are looking to try magnesium for sleep, the Cleveland Clinic suggests magnesium glycinate or magnesium citrate, though you should check with your doctor before starting a new supplement.
The same goes for magnesium’s impact on depression and stress.
“Depression is another area of interest when it comes to magnesium. I think depression, sleep, brain fog [improvements are] all related to the fact that magnesium assists with neurological pathways, and when they’re not functioning appropriately due to low levels, it can lead to mood disorders [and] sleep disorders ― but it’s not well understood,” Halperin said.
According to Milano, there have been a few randomised controlled trials exploring magnesium’s use for depression, and some studies have shown that magnesium did improve depressive symptoms, but additional research is necessary — the studies largely saw benefits in older adults 65 and up.
When it comes to stress, Wisniewski said studies suggest that taking magnesium and Vitamin B6 together can help with mental health and stress levels. But it’s unclear how much of a role magnesium plays. The study found that when magnesium was taken without Vitamin B6, it was not as effective for stress management.
Before starting any kind of supplement, speak with your doctor.
“Ultimately, it’s always a good idea to let your doctor know what supplements you’re taking,” Wisniewski said, adding that if your doctor isn’t available, then you can also speak with a pharmacist.
Again, it is possible to consume too much magnesium, which can result in diarrhoea, nausea, vomiting, low mood, muscle weakness, low blood pressure and an abnormal heartbeat, according to Halperin.
Additionally, Wisniewski said magnesium supplements can interfere with certain medications for issues like thyroid disorders or HIV, and can also interfere with certain antibiotics. It’s crucial that folks with any chronic conditions talk to a medical professional before taking magnesium.
Experts say you should follow a food-first approach in most cases.
“We often want our clients, patients, etc. to get micronutrients from food instead of relying on supplements to fix a problem,” Halperin said.
“If you’re worried you’re not getting enough magnesium or you’re hearing about the powers of magnesium, go ahead and start by incorporating magnesium-rich foods into your diet,” Milano added.
This includes green, leafy vegetables like spinach and Swiss chard, nuts, seeds, beans, legumes and whole grains. For reference, 1 ounce of almonds has 80 milligrams of magnesium, 1 ounce of pumpkin seeds have 150 milligrams and half a cup of black beans has 60 milligrams, according to the Cleveland Clinic.
“Maybe even playing around with the timing of those foods to see if that does reduce your anxiety and depression in heightened moments or if it does help you sleep a little bit better,” Milano added.
If you do decide you want to try magnesium supplements for any of the uses above, be sure to buy your supplement from a reputable source, she said.
“The FDA does not regulate supplements, and many markets throw out products with big health claims,” Milano said. Look for products that are USP-certified or NSF-certified, she noted. This will ensure they are safe and the company is following high-quality practices.
