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  • What is magnesium?

    Magnesium is an essential mineral for proper metabolism and nervous system functioning, including helping to maintain the electrical stability of the heart (see What It Is).
  • How do you know if you need to take magnesium?

    Although magnesium can be easily obtained through the diet and overt magnesium deficiency is not common, nearly half the U.S. population does not get adequate amounts of magnesium and can benefit from increasing magnesium intake from foods or supplementation. People most likely to get inadequate magnesium are adolescents and those over age 70. Conditions that may deplete magnesium include alcohol abuse, diabetes, diseases of the digestive tract, and use of medications such as Nexium and Prilosec. Inadequate intake of magnesium may modestly elevate blood pressure and increase the risk of osteoporosis and fractures. Early signs of magnesium deficiency include loss of appetite, nausea, vomiting, fatigue, and weakness (see Magnesium Deficiency and Insufficiency).
  • What does magnesium do?

    In addition to boosting intake, supplementing with magnesium may be helpful for conditions such as migraines and menstrual pain, and it is an effective laxative and antacid. It may also improve glucose status in people with prediabetes -- particularly if they are low in magnesium. It also helps control levels of vitamin D and can boost low levels. Maintaining adequate magnesium intake also has cardiovascular benefits, and maintaining a proper ratio of magnesium to calcium intake may have cognitive benefits (see What It Does).
  • What did CL's tests of magnesium find?

    Among the magnesium supplements selected for testing, four failed review because they contained less magnesium than listed or inaccurate amounts of other key ingredients (see What CL Found).
  • Which magnesium is best?

    CL selected a Top Pick for magnesium that is relatively well-absorbed, low in price (just pennies per pill), in a stable chemical form, and unlikely to cause diarrhea at moderate doses. CL also selected Top Picks for supplements combining magnesium with calcium, vitamin D, vitamin K, and/or boron.
  • How do forms of magnesium differ?

    Magnesium comes in many forms. Magnesium oxide tends to be less expensive than other forms but may also be less well absorbed and more likely to cause diarrhea. Forms that are more water soluble, such as magnesium chloride, citrate and many chelate forms (e.g., bisglycinate), may be better absorbed. Magnesium chloride is less likely to cause diarrhea and is recommended if you are taking a higher dose but it is best in liquid form rather than as a tablet, as it tends to attract and hold water, which can cause pills to disintegrate and create problems with supplement storage. Some magnesium chelates are also less likely to cause diarrhea but are bulky, requiring larger pills to get the same amount of elemental magnesium. Labels are required to show the amount of elemental magnesium in each serving, but you need to read labels carefully. See What to Consider When Buying for more about the different forms.
  • What's the right dose of magnesium?

    Most people can get the daily required magnesium from their diet. If you are not getting at least 300 to 400 mg of magnesium from your diet, consider a supplement that will get you to that level. Supplementing with about 200 mg should generally be sufficient and safe.

    When used to treat known deficiency, magnesium is often recommended at doses of 250 to 600 mg daily. However, unless treating a deficiency, limit your daily intake of magnesium from supplements and fortified foods to no more than 350 mg (the Tolerable Upper Intake Level), to avoid side-effects. You can easily get the rest of your required magnesium from your diet (see What to Consider When Using).

  • How can the recommended Daily Value (DV) for magnesium be higher than the Tolerable Upper Intake Level (UL)?

    The upper limit only applies to magnesium from supplements (and fortified foods). Side effects are not likely to occur from magnesium naturally in foods.
  • Safety and side effects of magnesium:

    Magnesium supplements may cause upset stomach, nausea, or diarrhea in some people. If using a powder form of magnesium, be sure to completely dissolve the powder in water before taking to avoid injury to the esophagus. Although rare, excessive intake of magnesium can cause thirst, low blood pressure, drowsiness, muscle weakness and slowed breathing. Be aware that magnesium can interact with certain supplements and drugs (see Concerns and Cautions).

Make sure you're choosing the best magnesium supplements approved in our tests!

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Magnesium supplements compared in this review

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Bluebonnet Magnesium Aspartate

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View Larger Image 7844_large_CountryLife-Calcium-BoneHealth-2022.png

Country Life Calcium Magnesium Complex

View Larger Image 7715_large_DouglasLaboratories-Magnesium-2022.png

Douglas Laboratories Chelated Magnesium

View Larger Image 7852_large_Flora-BoneHealth-VitaminDK-BoneHealth-2022.png

Flora Bone Health+ with Calcium, Magnesium, and Vitamin D & K

View Larger Image 7848_large_GNC-CalciumPlus-BoneHealth-2022.png

GNC Calcium Plus

View Larger Image 7718_large_GNC-Magnesium-2022.png

GNC Magnesium 250 mg

View Larger Image 7714_large_InnovixLabs-Magnesium-2022.png

Innovixlabs Advanced Magnesium

View Larger Image 7855_large_JarrowFormulas-BoneHealth-2022.png

Jarrow Formulas BoneUp

View Larger Image 7711_large_MagSRT-Magnesium-2022.png

Jigsaw Health MagSRT

View Larger Image 7856_large_LifeExtension-VitaminK-BoneHealth-2022.png

Life Extension Bone Restore with Vitamin K2

View Larger Image 7704_large_MegaFood-Magnesium-2022.png

MegaFood Relax + Calm Magnesium - Raspberry Lemonade

View Larger Image 7845_large_MetabolicMaintenance-CalMagPowder-BoneHealth-2022.png

Metabolic Maintenance Cal/Mag Powder

View Larger Image 7705_large_NaturalVitality-Magnesium-2022.png

Natural Vitality Calm - Raspberry-Lemon Flavor

View Larger Image 7706_large_NatureMade-Magnesium-2022.png

Nature Made Magnesium 250 mg

View Larger Image 7854_large_Naturelo-BoneHealth-2022.png

Naturelo Bone Strength Plant Calcium Complex With Magnesium, C, D3, K2, & Zinc

View Larger Image 7850_large_NaturesWay-CalciumD3-BoneHealth-2022.png

Nature's Way Calcium & Vitamin D3 - Citrus Flavored

View Larger Image 7853_large_NewChapter-BoneHealth-2022.png

New Chapter Bone Strength Take Care

View Larger Image 7702_large_NOW-Magnesium-2022.png

NOW Magnesium Glycinate

View Larger Image 7717_large_NutriColoogy-Magnesium-2022.png

NutriCology Magnesium Chloride Liquid

View Larger Image 7849_large_ProCapsLaboratories-D3-BoneHealth-2022.png

ProCaps Laboratories Andrew Lessman's Vitamin D3 1000

View Larger Image 7716_large_PuritansPride-Magnesium-2022.png

Puritan's Pride Magnesium Citrate

View Larger Image 7846_large_Solgar-Calcium-BoneHealth-2022.png

Solgar Calcium Magnesium Plus Boron

View Larger Image 7712_large_Solgar-Magnesium-2022.png

Solgar Magnesium Citrate

View Larger Image 7713_large_SpringValley-Magnesium-2022.png

Spring Valley Magnesium Citrate

View Larger Image 7707_large_Swanson-Magnesium-2022.png

Swanson Magnesium Lactate

View Larger Image 7708_large_TraceMinerals-Magnesium-2022.png

Trace Minerals Magnesium Gummies - Watermelon Flavor

View Larger Image 7851_large_TwinLab-Boron-BoneHealth-2022.png

TwinLab Tri-Boron Plus 12

View Larger Image 7709_large_Vitacost-Magnesium-2022.png

Vitacost Magnesium Citrate

You must be a member to get the full test results along with recommendations and quality ratings. You will get results for 29 magnesium supplements. Twenty of these products were selected for testing by and nine others passed the same testing through its voluntary Quality Certification Program.  

In this comprehensive review, you'll discover:
  • Which magnesium supplements failed our tests and which ones passed -- including combinations with calcium,vitamins D & vitamin K, and boron
  • CL's Top Picks among magnesium supplements based on form, quality and dose
  • The pros and cons of different forms of magnesium, including magnesium aspartate and orotate, magnesium citrate, magnesium chloride, magnesium bisglycinate, magnesium lactate and lactate dihydrate, magnesium oxide and magnesium-L-threonate
  • How to get adequate magnesium from food
  • The causes and symptoms of magnesium deficiency
  • How much magnesium to take to treat or prevent magnesium deficiency and other conditions
  • The evidence for and against using magnesium supplements for restless leg syndrome, leg cramps, migraines and more
  • Potential drug interactions and side-effects of magnesium supplements

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Additional Information
Tested through CL's Quality Certification Program prior to, or after initial posting of this Product Review.