- 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. Although magnesium can be easily obtained through the diet and overt magnesium deficiency is not common, many people do not get adequate amounts of magnesium and can benefit from increasing magnesium intake from foods or supplementation. Conditions that may deplete magnesium include alcohol abuse, diabetes, diseases of the digestive tract, and use of medications such as Nexium and Prilosec.
- What does magnesium do? Inadequate intake of magnesium may modestly elevate blood pressure and increase the risk of osteoporosis and fractures. In addition, 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).
- How much magnesium do I need? 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.
- What did CL's tests of magnesium find? Among the products ConsumerLab.com selected for testing, two magnesium-only supplements failed review because they contained less magnesium than listed or were contaminated with lead and two magnesium formulas failed for incorrect amounts of vitamin D, vitamin K, and/or boron (see What CL Found).
- Which magnesium supplement is best? Among the products that passed testing and were "Approved" for their quality, CL selected a Top Pick for magnesium that is low in price (just 6 cents per pill), well-absorbed, and in a stable chemical form. CL also selected Top Picks for combination formulas that include magnesium, such as those marketed for bone health that contain 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. (Be aware that, because magnesium chloride tends to attract and hold water, which can cause pills to disintegrate, magnesium chloride pills should be stored in a sealed container, away from other pills -- see Storage.) 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 high dose of magnesium but is best in liquid form rather than as a tablet. 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? When used as a treatment, magnesium is often recommended at doses of 250 to 600 mg daily (which is similar to the daily intake requirement in adults of about 400 mg). However, unless treating a deficiency, limit your daily intake of magnesium from supplements and fortified foods to no more than 350 mg (the Upper Tolerable 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).
- Safety and side effects of magnesium: Magnesium supplements may cause upset stomach, nausea, or diarrhea in some people. Although rare, excessive intake 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).
Magnesium Supplements Review (Including Calcium, Vitamins D & K, and Boron)
Find the Best Magnesium Supplement. Tests and Reviews of Popular Magnesium Supplements & CL's Top Picks.
Magnesium supplements compared in this review
365 Magnesium Cherry Fizz
Bluebonnet Rainforest AnimalZ Calcium Magnesium & Vitamin D3
BulkSupplements.com Magnesium Citrate
Caltrate Bone Health Advanced
Carlson Chelated Magnesium
Designs For Health Magnesium Malate
Doctor's Best High Absorption Magnesium
GNC Calcimate Complete
GNC Magnesium 500 mg
Jamieson Magnesium Ultra Strength 250 mg
Jarrow Formulas Bone-Up
Jigsaw Health MagSRT
KAL Magnesium Glycinate 400
Natural Vitality Natural Calm Plus Calcium - Raspberry-Lemon Flavor
New Chapter Bone Strength take care
NOW Magnesium Citrate
Pioneer Children's Cal Mag & D - Cocoa
Pure Encapsulations UltraMag Magnesium
Puritan's Pride Calcium Magnesium Vitamin D3
Puritan's Pride Chelated Calcium Magnesium Zinc
Rainbow Light Food-Based Calcium With Magnesium & Vitamin D3
Solgar Calcium Magnesium Plus Boron
Solgar Chelated Magnesium
Standard Process Calcium Lactate
Swanson Chelated Magnesium
Thorne Basic Bone Nutrients
Vitacost Magnesium Citrate
Vitalite Now! Calcium & Magnesium Plus
(11/5/19) The distributor of a magnesium supplement that was Not Approved for containing less magnesium than claimed informed us of a misprint on the label and that it has recalled the lot that we tested.
Details are found in the Updates section of the full report.
- Which magnesium and calcium/magnesium supplements failed our tests and which ones passed
- CL's Top Picks among magnesium-only supplements and combination products with calcium, boron, vitamin D and vitamin K 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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