The 7 Best Magnesium Supplements of 2021, According to a Dietitian

How to choose a magnesium supplement that is right for you

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Magnesium is an essential mineral and a cofactor for hundreds of enzymatic reactions in the body. This powerful mineral is involved in energy production, protein synthesis, and cellular communication. It is a necessary mineral that is responsible for many processes in the body including “maintaining normal nerve and muscle function, bone health, regulating blood pressure and blood sugar, and supporting the immune system” says Dr. Ben E. Paxton, MD a board-certified interventional radiologist practicing in Prescott, AZ.

It is estimated that half of the United States population is consuming inadequate amounts of magnesium. According to Dr. Paxton, “low levels of magnesium may be linked with depression, heart problems, and Type 2 diabetes”. Fortunately, magnesium is fairly easy to obtain through food as it is widely distributed in plant and animal foods such as leafy greens, legumes, nuts, seeds, and whole grains. A varied diet will usually ensure adequate magnesium intake, however, for picky eaters or those at risk for magnesium deficiency, magnesium can be obtained from supplements.

There are numerous forms of supplemental magnesium available—including magnesium oxide, magnesium sulfate, magnesium glycinate, magnesium chloride, and magnesium citrate, as well as a number of amino acid chelates like magnesium aspartate. The best type of magnesium to supplement depends on your goals and needs. For those looking to alleviate constipation, opting for magnesium oxide or citrate might be best. Magnesium glycinate or chloride might be best to support sleep and/or relaxation. As always, it is best to consult with a doctor or healthcare provider to find out what type of magnesium is best for you.

What to Look for in Magnesium Supplements


It is important to check the ingredients list when shopping for a new supplement. Different products use different ingredients to make the capsules that contain the magnesium and those ingredients may or may not fit with your dietary restrictions or preferences. In addition, some supplements may include complementary ingredients; do your research to make sure these ingredients are right for you. Be mindful of potential allergens and always reach out to your health care provider if you are unsure about ingredients in a product. 


Look for certifications from independent, third party testing companies such as, NSF International, and USP. These organizations provide quality testing and allow products that pass their tests to display a seal of quality assurance. These seals indicate the product was properly manufactured, contains the ingredients listed on the label, and does not contain harmful levels of contaminants. 


Though most of the supplements reviewed are generally recognized as safe, you may need to consult a healthcare provider if you are already taking certain medications or supplements. It is always important to remember that just because a supplement is sourced from natural ingredients, they can still be incredibly powerful. Start a new supplement with the lowest dose possible being mindful of unwanted changes and increase as tolerated. 

Magnesium Dosage

Always speak with a healthcare professional before adding a supplement to your routine to ensure that the supplement is appropriate for your individual needs and which dosage to take.

The recommended daily allowance (RDA) for magnesium is as follows:

  • Birth to 6 months - 30 mg
  • 7–12 months - 75 mg
  • 1–3 years - 80 mg
  • 4–8 years - 130 mg
  • 9–13 years - 240 mg
  • 14–18 years - males 410 mg / females 360 mg
  • 19–30 years - males 400 mg / females 310 mg / pregnancy 350 mg / lactation 310 mg
  • 31–50 years - males 420 mg / females 320 mg / pregnancy 360 mg /  lactation 320 mg
  • 51+ years - Males 420 mg / females 320 mg

Frequently Asked Questions

  • What is the best time to take magnesium?

    If you are taking magnesium citrate, it may be best to take the supplement in the evening due to its laxative effect. Magnesium supplements that are geared toward sleep support or decreased anxiety might be best used when consumed in the evening as well. In general, the best time to take any supplement is whenever you are most likely to remember.

    Magnesium supplements might interfere with certain medications such as levothyroxine, antibiotics and some statin drugs. Consumers that are on prescription medications should always consult with a healthcare provider or pharmacist to discuss possible contraindications.

  • How does magnesium help with sleep?

    The role magnesium plays in supporting optimal sleep is not fully understood. One possible explanation is that magnesium is an agonist of GABA, a naturally occurring amino acid that works as a neurotransmitter. GABA is known to decrease activity in the nervous system which can lead to relaxation. More research is needed to determine magnesium’s specific effect on sleep.

How We Select Supplements

Our team works hard to be transparent about why we recommend certain supplements; you can read more about our dietary supplement methodology here

We support supplements that are evidence-based and rooted in science, as well as clinically tested and approved for use in humans. We value certain product attributes that we find to be associated with the highest quality products. These attributes include non-GMO, Organic, and allergy-friendly products that are free of most artificial ingredients including colors, flavors, preservatives, and sweeteners. When possible, we recommend products that are third-party tested and certified.

It's important to note that the FDA does not review dietary supplements for safety and effectiveness before they go to market. Our team of experts has created a detailed, science-backed methodology to choose the supplements we recommend.

Here, the best magnesium supplements, according to a registered dietitian.

Best Overall: Klaire Labs Magnesium Glycinate Complex

  • Vegetarian friendly

  • Hypoallergenic

  • Lower dose of magnesium; you might need to take 2-3 capsules to see benefits

Klaire Labs Magnesium Glycinate Complex provides 100 milligrams of a bisglycinate blend to support bone health and restful sleep. In addition to overall health, magnesium bisglycinate has been shown to help relieve pregnancy induced leg cramps in pregnant women. Combining magnesium with the amino acid glycine creates a unique compound that is highly bioavailable and well tolerated.

This product is free of the following common allergens: milk and casein, eggs, fish, shellfish, tree nuts, peanuts, wheat, gluten, soybeans, and yeast. We like that it contains no artificial colors, flavors, or preservatives making it an extremely safe choice for those with the most restrictive dietary needs. This magnesium supplement is great for overall magnesium needs.

Key Nutrients: Magnesium | Vegan: No, but vegetarian | Gluten Free: Yes | Organic: No

Best Budget: Nature’s Bounty Magnesium 500 mg

  • Affordable

  • Free of common allergens

  • High dose of magnesium might not be suitable for everyone

Magnesium supplements do not have to cost an arm and a leg. This bottle of 200 magnesium tablets is less than ten dollars and each tablet provides 500 milligrams of magnesium (119 percent of the daily recommended intake of Magnesium) as magnesium oxide. Magnesium oxide may be beneficial with decreasing the amount of headaches experienced however more research is needed to be done in order to identify the specific benefits of this type of magnesium.

These tablets are coated for easy swallowing and support bone and muscle health, maintaining bone mineralization. We like that they are free of artificial flavors and sweeteners and are also gluten-free.

Although this product does not feature a third-party certification from companies such as NSF or, this supplement still makes the list as Nature’s Bounty is committed to producing high-quality, safe supplements that are subjected to numerous quality tests and assays throughout the manufacturing process.

Key Nutrients: Magnesium Oxide | Vegan: Yes | Gluten Free: Yes | Organic: No

Best Glycinate: Pure Encapsulations Magnesium (Glycinate)

Pure Encapsulations Magnesium Glycinate
  • Hypoallergenic

  • Free of common allergens

  • Larger capsule compared to some other products

Magnesium glycinate is a water soluble form of magnesium which might make it more easily absorbed. Unlike other forms of magnesium, glycinate is less likely to have a laxative effect which might make it a better choice for those looking for sleep, mood, cognition and/or overall health and wellbeing support. One capsule of Pure Encapsulations Magnesium Glycinate contains 120 milligrams or 29 percent of the daily recommended intake of magnesium.

Pure Encapsulations supplements are made with only premium ingredients sourced from trusted suppliers and guided by their nutritional experts. Their products are then carefully manufactured and tested to verify their potency and purity. All Pure Encapsulations products are free from many common allergens like wheat, eggs, tree nuts and peanuts, gluten, artificial colors, flavors and sweeteners, coatings and shellacs, GMOs, unnecessary binders, fillers and preservatives making them safe for most consumers.

Key Nutrients: Magnesium Glycinate | Vegan: Yes | Gluten Free: Yes | Organic: No

Best Citrate: NOW Foods Magnesium Citrate 200 mg

  • Affordable

  • Vegetarian formula and coating

  • Two tablets is one serving

NOW Foods is a leader in the supplement industry and is a budget-friendly choice that does not skimp on purity or quality of products. NOW’s magnesium citrate is Kosher certified, vegan, non-GMO and keto friendly. In addition to these certifications, this product is also free of wheat, gluten, soy, milk, egg, fish, shellfish or tree nut ingredients.

Buyers can choose to take one tablet containing 200 milligrams of magnesium from magnesium citrate or follow the serving size and take two tablets for 400 milligrams of magnesium citrate. Magnesium citrate is often used for constipation and gastrointestinal distress. When taking a new supplement, especially one for its laxative effect, it is best to start with a low dose and work up to a full dose. As always, consult with a doctor or health care provider for dosing.

Key Nutrients: Magnesium Citrate | Vegan: Vegetarian | Gluten Free: Yes | Organic: No

Best for Sleep: Natural Vitality Calm Sleep Magnesium Citrate

Natural Vitality CALM Sleep
  • Blend of curated nutrients to support sleep 

  • Free of artificial flavors and added sugars

  • Only available in one flavor

Natural Vitality’s Calm Sleep is our top choice for a magnesium that promotes sleep. We love the blend of sleep supporting ingredients and the brand’s commitment to quality. The featured ingredient in this powdered supplement is a blend of magnesium glycinate and carbonate. Though this product is not third-party tested, we like that it is non-GMO verified, vegan, and combines a potent blend of sleep-supporting ingredients.

In addition to calming magnesium, you get Suntheanine+, a patented form of the relaxing amino acid L-theanine); gamma-aminobutyric acid (GABA), a neurotransmitter that helps calm brain activity; and melatonin, the hormone that helps control your natural sleep-wake cycle. This product is Non-GMO verified, vegan, gluten-free and sugar-free. For occasional sleeplessness, start with 1 teaspoon (2 grams) and gradually increase to two teaspoons (4 grams) daily.

Key Nutrients: Magnesium, GABA, Melatonin, L-Theanine | Vegan: Yes | Gluten Free: Yes | Organic: No

Best for Anxiety: Thorne Research Magnesium Bisglycinate Powder

  • NSF certified for sport

  • Sugar-, artificial flavor-, and color-free

  • More expensive than other supplements

More research is needed to directly link a deficiency in magnesium to anxiety levels, however, it is safe to say that adequate intake of magnesium is important for optimal production of neurotransmitters. One scoop of Thorne’s Magnesium Bisglycinate Powder provides 48 percent of the recommended daily intake of magnesium. Magnesium glycinate has less of a laxative effect than other forms and is thought to be more effective for relaxation.

Every Thorne product is made with the purest possible ingredients—without gluten or other major allergens (eggs, tree nuts, peanuts). This product also contains no soy, dairy, yeast, shellfish, or fish. As an added safety bonus, this is a NSF Certified for Sport product which means it is tested for compliance with label claims and to ensure the absence of 280 substances banned by many major athletic organizations.

Key Nutrients: Magnesium Bisglycinate | Vegan: Yes | Gluten Free: Yes | Organic: No

Best for Muscle Cramps: Rainbow Light Magnesium Calcium+ Food Based Tablets

  • Provides blend of nutrients which may help with absorption

  • Affordable

  • Herbal support blend may not be ideal for all customers 

About 50 to 60 percent of all the magnesium in the body is found in the skeleton and the remainder is found in soft tissue, primarily in muscle. A very small study of male recreational runners who consumed a low magnesium diet found that supplementation with 500 milligrams of magnesium decreased muscle soreness. Rainbow Light’s Magnesium Calcium+ food based tablets contain over 300 milligrams of magnesium from a blend of different forms.

In addition to magnesium, this product includes calcium, vitamin B6, vitamin D3, vitamin C and an herbal muscle support blend to boost efficacy. This product is vegetarian and contains no gluten, wheat, milk, tree nuts, peanuts, soy, eggs, fish or shellfish. As an added bonus, we like that Rainbow Light’s bottles are 100 percent recycled/recyclable EcoGuard BPA-free.

Though this specific product is not reviewed by third-party certification sites, Rainbow Light’s products are manufactured in compliance with Good Manufacturing Practices (GMPs) set forth by the FDA, and they take care in inspecting the ingredients used in their products.

Key Nutrients: Magnesium, Vitamin C, Vitamin D3, Calcium, Manganese, Vitamin B6, Muscular support blend and digestive support complex | Vegan: No, but vegetarian | Gluten Free: Yes | Organic: No

Final Verdict

Klaire Labs Magnesium Glycinate Complex (view at Amazon) is our top magnesium supplement pick. Providing 100 milligrams of a Bisglycinate blend to support bone health and restful sleep, this product is highly bioavailable and well tolerated.

If you're looking for a powder version of a magnesium supplement, try Thorne’s Magnesium Bisglycinate Powder (view at Amazon). One serving provides 48 percent of the recommended daily intake of magnesium, and magnesium glycinate has less of a laxative effect than other forms and is thought to be more effective for relaxation.

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Article Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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