The 6 Best Magnesium Supplements, According to Registered Dietitians
Our experts recommend supplements from Thorne and Klean Athlete.
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YOU LIKELY KNOW that magnesium is a mineral. But what exactly does it do for you?
“Magnesium helps maintain a healthy heart rate, so you literally can’t live without it,” says Kim Yawitz, RD, gym owner of CrossFit 26 in St. Louis, MO. “But heartbeat aside, magnesium plays a key role in more than 300 chemical reactions in the body. It’s involved in DNA repair, protein synthesis, bone health, fluid and electrolyte balance, energy production, and muscle contraction—just to name a few.”
Best Magnesium Supplements
As Yawitz explains, because magnesium plays a role in many important bodily functions, a low dietary intake could lead to health problems. “Studies have linked low magnesium intake with an increased risk of type 2 diabetes, high blood pressure, inflammation, heart disease, stroke, migraine headaches, asthma, and colon cancer,” she says.
Before turning to magnesium supplements, tweaking your diet to contain more magnesium-rich foods may be a good move. “The best way to get enough magnesium is to eat lots of nuts, seeds, leafy greens, whole grains, and legumes,” says Yawitz. “But if you’re among the estimated 60 percent of adults who don’t do that, a supplement can help you to cover your bases.”
Unfortunately, as Yawitz shares, diagnosing magnesium deficiency is pretty difficult. “It doesn’t always show up on a lab test because most magnesium is stored in the bones.” As always, consult a healthcare professional before adding a new product to your routine, and if you’re looking for a supplement, here are some dietitian-recommended picks to try.
What to Consider
Safety and Testing
Because supplements are not regulated by the FDA like food and medications are, it’s important to make sure you’re purchasing your magnesium supplement from a reputable company that has participated in third-party testing to ensure purity and potency.
You’ll also want to be knowledgeable of all ingredients used in the magnesium product, as some may interact with other medications you take. “Before choosing a magnesium supplement, always scan the label for other ingredients," says registered dietician Melissa Mitri, RD. "Some supplement companies use blends that contain multiple active ingredients, and it’s important to know what you’re taking,”
Form of Magnesium
Magnesium is combined with organic or inorganic salts that all have variable levels of absorbability and side effects. Magnesium oxide is the most inexpensive form of the mineral, but also the least absorbable and has the highest rate of digestive side effects.
“To choose the right form of magnesium, consider your health goals and why you’re taking it," says Mitri. "Then, choose a form that best fits your current needs.” Magnesium citrate has more of a laxative effect than other forms, making it ideal for constipation, while magnesium L-threonate has been studied for its effects on memory and cognition.
Dose
Magnesium supplements can be found in doses of 100 milligrams or less up to 500 milligrams or more. “I would caution people to start slow when supplementing and not automatically go to the higher end of daily intake (400 mg),” says registered dietician Sarah Schlichter, MPH, RDN, of Bucket List Tummy. The RDA for magnesium from food is 400 to 420 milligrams per day for adult males and 310 to 320 milligrams per day for adult females.
While you won’t have side effects of too much magnesium from food, supplements could create a gastrointestinal upset or even cause toxicity with symptoms of nausea, vomiting, muscle weakness, and hypotension. The tolerable upper limit of magnesium supplements is 350 milligrams per day.
How We Selected
To find the best magnesium supplements on the market, we asked experts for their recommendations and criteria for selecting high-quality options, which include absorbable forms of magnesium, testing, and appropriate dosing. Every one of our picks is certified by either NSF, USP, or Informed Choice and has been tested for purity and potency, ensuring a high-quality supplement safe from heavy metals and toxins. Read on for our expert-approved picks.
Pros
- Highly absorbable form of magnesium
- Easy on the stomach
- Moderate dose
- No artificial flavors, colors, or additives
Cons
- Requires that you drink it in 8 ounces of water
For a magnesium supplement that’s easy on the stomach, highly absorbable, and thoroughly tested, Thorne Magnesium Bisglycinate powder comes out on top. Each scoop is mixed with 8 ounces of water and contains 200 milligrams of magnesium. If you’ve experienced stomach troubles after taking magnesium in the past, this supplement may be a better option. “Since this form of magnesium doesn’t appear to have as much of a laxative effect as other magnesium products, many people seem to tolerate it better and have fewer unwanted digestive symptoms,” says Mitri.
If you’re looking for a better night’s sleep or to improve your stress levels, this form of magnesium may have some benefits. Research has found a cycle effect between stress and low magnesium levels. Low levels can make you more susceptible to stress, while high stress can deplete magnesium stores. “Magnesium bisglycinate is a form of magnesium that contains glycine, a neurotransmitter shown to promote rest and relaxation,” says Mitri.
Read More: Best Supplements for Men
| Type | Magnesium Bisglycinate |
|---|---|
| Dose | 200 milligrams |
| Form | Powder |
| Certifications | NSF Certified |
Nature Made Magnesium Citrate
Pros
- Affordable and widely available
- Highly absorbable
- Single dose is two pills, easily halved if needed
Cons
- Could have a laxative effect
- May be difficult to swallow for some people
At just $0.47 per dose, Nature Made Magnesium Citrate capsules are our favorite budget-friendly magnesium supplement. Even at a lower price, this choice is USP certified, so you know you’re getting everything the label says and nothing it doesn’t. Magnesium citrate is much more absorbable than magnesium oxide and generally easier on the stomach as well.
However, magnesium citrate is also the type of magnesium that is used in laxatives as it helps draw water into the intestines, although it won’t have the same effect as over the counter laxative medications containing the mineral. Each two-pill dose is 250 milligrams, so it can easily be halved to 125 milligrams if needed.
| Type | Magnesium Citrate |
|---|---|
| Dose | 250 milligrams |
| Form | Softgel capsules |
| Certifications | USP |
“I love the Klean Athlete brand; since they are NSF certified and have a rigorous research process, I always recommend it to athletes,” says Schlichter. This magnesium supplement features 125 milligrams of magnesium from magnesium glycinate. This form of magnesium is combined with the amino acid glycine, making it more absorbable than some other forms of magnesium and with less digestive side effects.
“I would caution people to start slow when supplementing and not automatically go to the higher end of daily intake (400 milligrams),” says Schlichter. You can easily start with a low to moderate dose of 125 milligrams with one capsule, taking another dose if more is needed.
| Type | Magnesium glycinate |
|---|---|
| Dose | 120 milligrams |
| Form | Capsule |
| Certifications | NSF Certified |
Pros
- Easy to chew and take
- No added sugars
- Certified gluten-free and vegan
- Pre and probiotics added
Cons
- To get the 1 billion CFUs of probiotics, four gummies are needed (with 400 milligrams of magnesium)
If you have trouble swallowing pills, Garden of Life Dr. Formulated Magnesium Gummies may be the best option. Every one-gummy serving contains 100 milligrams of magnesium citrate, one gram of prebiotic fiber, and 250 million CFUs of the probiotic Bacillus subtilis. These gummies are formulated to help promote relaxation and support gut, muscle, and bone health.
If you’re hoping you get your magnesium and probiotics in one supplement, this gummy does have it all, but a dose of 400 milligrams of magnesium is needed for 1 billion CFUs of probiotics, which is above the tolerable upper limit for supplemental magnesium. “Magnesium-rich foods are generally rich in other important nutrients, like fiber, antioxidants and micronutrients, so getting more magnesium through the diet should be a priority,” says Schlichter.
| Type | Magnesium Citrate |
|---|---|
| Dose | 400 milligrams (for 4 gummies) |
| Form | Gummy |
| Certifications | NSF Certified |
Pros
- Formulated for recovery and bone and muscle health
- Highly absorbable
- Affordable
Cons
- One dose is two pills, which may be difficult for some people to swallow
If you prioritize recovery after hard workouts, GU Roctane Magnesium Plus provides magnesium and other nutrients to support healthy muscles and bones while optimizing recovery. Each serving of two pills has 200 milligrams of easily absorbable magnesium citrate, 250% DV vitamin D, 133% DV vitamin K, and 182% DV zinc. Vitamin D and Vitamin K work together to reduce the risk of fractures while supporting heart health by inhibiting calcification of the vascular system.
Including zinc as zinc gluconate helps support muscle cell activation, proliferation, and differentiation, all of which help promote muscle regeneration. This is especially important for athletes, as research has found that the oxidative stress induced by exercise may actually lead to the depletion of zinc levels in the body.
| Type | Magnesium Citrate |
|---|---|
| Dose | 200 milligrams |
| Form | Capsules |
| Certifications | Informed Choice |
Pros
- Free from gluten, dairy, and soy
- Highest rate of absorption among all types of magnesium
- Clinically shown to support cognition
Cons
- One serving is 3 pills, which may be a lot for some people to take
Magnesium L-Threonate may be the best option if you’re looking to support sleep, focus, and overall cognition. Research has found that this form of magnesium is the most absorbable and retainable compared to magnesium combined with chloride, citrate, glycinate, and gluconate. It also appears to have the largest impact on brain and spinal cord magnesium levels.
To support relaxation and sleep, magnesium plays a role in melatonin regulation and binds to GABA receptors in the brain, helping to settle down nerve activity and promote relaxation. One serving of Monumentous Magnesium L-Threonate is 145 milligrams of magnesium, obtained from 2 grams of Magtein®, the exact compound and amount used in studies showing improvements in memory and cognition.
| Type | Magnesium L-Threonate |
|---|---|
| Dose | 145 milligrams |
| Form | Capsules |
| Certifications | Informed Choice |
Magnesium Supplement Benefits
With all the above being said, the active set may particularly benefit from magnesium supplements. “There’s some evidence that athletes may need more magnesium than less active adults, possibly because the body uses more magnesium during exercise,” says Yawitz. “In one small study, magnesium supplements appeared to help reduce muscle damage after a multistage bike race. Overall, though, the research is mixed on whether supplements are helpful for exercise performance.”
In healthy adults, Yawitz also points out, there’s some evidence that magnesium supplements may improve sleep and mood in those prone to insomnia and depression.“In one meta-analysis, adults taking magnesium supplements fell asleep an average of 17 minutes faster and slept 16 minutes longer per night than those taking a placebo,” she says. “And in another large study, young adults taking magnesium reported better sleep quality than those who didn’t take it.” In yet another study, Yawitz explains that adults with mild to moderate depression saw significant improvements in depression and anxiety symptoms after taking magnesium supplements for just six weeks.
Taking magnesium supplements may be useful for those with chronic disease. “One meta-analysis also suggests that magnesium supplements could help reduce the odds of type 2 diabetes, heart disease, hypertension, and other chronic illnesses by reducing systemic inflammation,” says Yawitz.
How Much Magnesium Do You Actually Need Everyday?
Healthy adult males require about 400 to 420 milligrams (mg) of magnesium per day, says Yawitz. “Your ideal supplement dose depends on how much you’re getting through your diet,” she says, adding that an app like Cronometer can help you estimate your daily intake, so you don’t overdo it on supplements (which can cause diarrhea, nausea, vomiting, and other side effects).
“Regardless of dietary intake, I always suggest starting at a low dose of 100 to 150 milligrams (mg) per day and taking no more than 300 mg per day,” says Yawitz. “Keep in mind that certain medications—like antacids and laxatives—often contain magnesium,” she continues, stressing that you should check with your doctor or pharmacist before starting a supplement, especially if you take prescription or over-the-counter meds.
Which is the Best Form of Magnesium to Take?
There are several different types of magnesium supplements on the market. Kieran McSorley, RD, of Brentwood Physiotherapy, goes by the quote, “The best form of magnesium is the one that your body absorbs best." As McSorley highlights, magnesium is available in several forms, including magnesium oxide, magnesium citrate, magnesium glycinate, and magnesium chloride. “The form of magnesium you choose may depend on the reason you are taking it, as well as any potential side effects you may experience,” he says. “Some forms of magnesium can cause digestive upset, while others are better tolerated. It's important to work with a healthcare provider to determine the best form of magnesium for your individual needs.”
Pallini Winnifred, RDN, of FitDominium says that the best form of magnesium is the kind that your body can absorb and use the most easily. “The bioavailability of magnesium, which refers to how well the body can absorb and use the mineral, might vary between different forms,” says Winnifred. “Many people handle some magnesium salts well, including magnesium citrate and magnesium glycinate, which are both highly accessible forms of the mineral. On the other hand, magnesium oxide is less bioavailable, but because it is cheap, it is often used as a dietary supplement.”
Some registered dietitians such as Mary Sabat, RDN, owner of BodyDesigns, single out magnesium glycinate in particular. “It is a chelated form of magnesium that is easily absorbed by the body, making it an effective way to supplement your magnesium levels,” she says.
Side Effects of Magnesium Deficiency
You need adequate magnesium to live. “Magnesium is important for many body functions, such as energy metabolism, protein synthesis, and nerve function,” says Winnifred.
According to Winnifred, here are just a few of the not-so-fun symptoms that may result from not getting enough magnesium: Exhaustion, muscle cramps, weakness, irritability, and trouble sleeping. “Magnesium deficiency can, in extreme situations, cause seizures, cardiac problems, and other medical complications,” she adds. As always, consult with a trusted healthcare professional if you’re concerned you’re not getting enough magnesium in your diet.
Foods Highest in Magnesium
For adult men, says Winnifred, it is advised to strive for a daily magnesium intake of 400 to 420 mg. To get your fix, she recommends dark, leafy greens like spinach (1 cup has 157 mg of magnesium), almonds (1 oz contains 80 mg of magnesium), and black beans (1 cup contains 120 mg of magnesium). Salmon, avocados, and bananas are also excellent suppliers of magnesium,” she adds.
Sabat also calls out the dark leafy green Swiss chard and pumpkin seeds for their impressive nutrition specs, particularly when it comes to magnesium. “A one cup serving of cooked Swiss chard contains 150mg, and a one ounce serving of pumpkin seeds contains 150mg,” she says, noting that spinach and Swiss chard are both excellent sources of vitamin A and vitamin C, while pumpkin seeds are also a good source of fiber and protein.
Meet the Experts
- Melissa Mitri, MS, RD, a registered dietitian, nutrition writer and owner of Melissa Mitri Nutrition.
- Sarah Schlichter, MPH, RDN, is a registered dietitian and writer at Bucket List Tummy.
- Kieran McSorley, RD, is a registered dietician at Brentwood Physiotherapy.
- Kim Yawitz, RD, is a registered dietitian and gym owner of CrossFit 26 in St. Louis, MO
- Pallini Winnifred, RDN, is a registered dietitian at FitDominium.
- Mary Sabat, M.S., RDN, is a registered dietitian and owner of BodyDesigns.
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