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Magnesium Supplements
Compare US magnesium supplements by form, elemental daily dose, price and testing status. Understand glycinate versus citrate, sleep evidence and the US supplemental upper limit.
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Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Testing evidence
Evidence status
Verified independent evidence
Manufacturer statement
Certificate of Analysis for "Pure Encapsulations Magnesium (glycinate)" showing Report Number 4321342-0, Report Date 14-Dec-2023, and testing by Eurofins Food Chemistry Testing Madison / Food Integrity Innovation-Madison; result: Magnesium 121 mg/serving.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Testing evidence
Evidence status
Verified independent evidence
Manufacturer statement
Certificate of Analysis for "Pure Encapsulations Magnesium (glycinate)" showing Report Number 4321342-0, Report Date 14-Dec-2023, and testing by Eurofins Food Chemistry Testing Madison / Food Integrity Innovation-Madison; result: Magnesium 121 mg/serving.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Testing evidence
Evidence status
Testing claimed
Manufacturer statement
Amazon listing and Vitamatic product page use marketing-only language such as "Lab Tested" and "GMP" / "Made in a GMP-compliant Facility," but I found no independently verifiable COA, lab report, or certifying-body registry entry for this specific product.
Compare elemental magnesium, not compound weight. A 1,420 mg bisglycinate compound can supply 200 mg elemental magnesium. The rest is the accompanying compound. Use the declared elemental amount; do not infer it from a generic conversion percentage. Read the dose guide ↓
Certificate of Analysis for "Pure Encapsulations Magnesium (glycinate)" showing Report Number 4321342-0, Report Date 14-Dec-2023, and testing by Eurofins Food Chemistry Testing Madison / Food Integrity Innovation-Madison; result: Magnesium 121 mg/serving.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
NOW’s own product imagery says: “Intertek GMP certification means that every aspect of the NOW supplement manufacturing process has been audited, including our laboratory/testing methods (for stability, potency, and product formulation).” The product page also shows: “This bottle is made from 100% PCR (post-consumer recycled) resin.”
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Amazon listing and Vitamatic product page use marketing-only language such as "Lab Tested" and "GMP" / "Made in a GMP-compliant Facility," but I found no independently verifiable COA, lab report, or certifying-body registry entry for this specific product.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer site says: "Every batch third-party tested for purity and potency. What you read on the label is what is in the tub." Product page also says "UK made, batch tested" and "Certified facilities, every batch."
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer product page says "Lab Tested" and the Vitacost listing says "GMP Quality Assured" / "Made With B6 & Oxide" for Vitamatic, Magnesium Citrate with B6, 180 Vegetarian Capsules, but I found no independently verifiable third-party lab report or certifying-body registry entry for this specific product.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Nature Made says many products are “verified by the United States Pharmacopeia (USP), an independent organization that sets rigorous standards for purity, potency, and manufacturing,” and that products meeting USP standards display the USP seal.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Life Extension says: "We are happy to provide a summary of the reports we receive from the contract manufacturers and the independent laboratories that test both our raw materials and final products. We can do this for every supplement, from our best-sellers down to our niche formulations."
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer site says "TESTED FOR QUALITY" and "Every Natural Vitality product is produced under strict cGMP protocols established by the FDA. Our comprehensive quality control system monitors each production phase to ensure consistent excellence."
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
NSF International public dietary supplement listings show Garden of Life magnesium powder products, including "Garden of Life Magnesium Raspberry" and "Garden of Life Magnesium Orange," under NSF/ANSI Standard 173.
Laboratory
Not recorded
Certification body
Not recorded
Batch
Not recorded
Batch-specific report
Not established in this record
Report date
Not recorded
Evidence checked
2026-09-15 18:30:33
Why this score?
Testing & evidence
4/20
Ingredient/formulation quality
17/25
Value
13/20
Dose transparency
14/15
Manufacturer transparency
9/10
Label/ingredient transparency
10/10
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Certificate of Analysis for "Pure Encapsulations Magnesium (glycinate)" showing Report Number 4321342-0, Report Date 14-Dec-2023, and testing by Eurofins Food Chemistry Testing Madison / Food Integrity Innovation-Madison; result: Magnesium 121 mg/serving.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
NOW’s own product imagery says: “Intertek GMP certification means that every aspect of the NOW supplement manufacturing process has been audited, including our laboratory/testing methods (for stability, potency, and product formulation).” The product page also shows: “This bottle is made from 100% PCR (post-consumer recycled) resin.”
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Amazon listing and Vitamatic product page use marketing-only language such as "Lab Tested" and "GMP" / "Made in a GMP-compliant Facility," but I found no independently verifiable COA, lab report, or certifying-body registry entry for this specific product.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer site says: "Every batch third-party tested for purity and potency. What you read on the label is what is in the tub." Product page also says "UK made, batch tested" and "Certified facilities, every batch."
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer product page says "Lab Tested" and the Vitacost listing says "GMP Quality Assured" / "Made With B6 & Oxide" for Vitamatic, Magnesium Citrate with B6, 180 Vegetarian Capsules, but I found no independently verifiable third-party lab report or certifying-body registry entry for this specific product.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Nature Made says many products are “verified by the United States Pharmacopeia (USP), an independent organization that sets rigorous standards for purity, potency, and manufacturing,” and that products meeting USP standards display the USP seal.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Life Extension says: "We are happy to provide a summary of the reports we receive from the contract manufacturers and the independent laboratories that test both our raw materials and final products. We can do this for every supplement, from our best-sellers down to our niche formulations."
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer site says "TESTED FOR QUALITY" and "Every Natural Vitality product is produced under strict cGMP protocols established by the FDA. Our comprehensive quality control system monitors each production phase to ensure consistent excellence."
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Active form
Whole-food chelate (organic brown rice protein magnesium chelate)
NSF International public dietary supplement listings show Garden of Life magnesium powder products, including "Garden of Life Magnesium Raspberry" and "Garden of Life Magnesium Orange," under NSF/ANSI Standard 173.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
One-time purchase prices; delivery and conditional discounts excluded. Daily cost uses the recorded label serving. Comparison amounts are not personal dose recommendations. Unknown Prime eligibility is not treated as confirmed.
Magnesium forms explained
The current US set contains citrate and glycinate. Other forms below provide label context, not a ranking of unlisted products. The evidence section links to the supporting US sources.
Citrate
Magnesium salt
On the label
Read the elemental amount
Different use
Also sold as a laxative medicine
A supplement capsule and a bowel-preparation liquid are different products; follow the correct instructions.
Bisglycinate (Glycinate)
A glycine-associated form
Label terminology
Glycinate and bisglycinate commonly appear
Check blends
Read all named magnesium ingredients
Do not assume a sleep or gentle-on-stomach claim establishes superiority for every product.
Oxide
Magnesium salt
Compare
Elemental amount per serving
Evidence context
Absorption differs between salts
High compound magnesium content does not itself establish high absorbed intake.
L-Threonate
Another magnesium form
Read both figures
Compound mass and elemental magnesium
Current coverage
Not represented in the US comparison
A brain-health label alone does not establish better clinical outcomes than other forms.
Malate
A malic-acid-associated form
Compare
Declared elemental amount
Current coverage
Not represented in the US comparison
Do not infer an energy or muscle benefit from the form name.
Taurate
A taurine-associated form
Compare
Elemental magnesium and other actives
Current coverage
Not represented in the US comparison
A heart-health claim needs its own evidence.
Hydroxide
Magnesium salt also used in medicines
Check
Supplement Facts versus Drug Facts
Use
Follow the specific product instructions
Do not copy a laxative or antacid serving into a daily supplement routine.
During pregnancy the adult RDA is 350 mg at ages 19–30 and 360 mg at ages 31–50. Lactation uses the corresponding nonpregnant adult amounts. These references differ from the 420 mg labeling Daily Value.
The 350 mg distinction
The adult upper limit is 350 mg/day from supplements and medications; it excludes naturally occurring food magnesium. The table’s 200–400 mg context badge is not this limit. A 400 mg supplement can receive that badge while exceeding the US limit. NIH safety guidance.
Compound weight versus elemental dose
Use the magnesium amount in Supplement Facts. In the current data, one product headlines 800 mg citrate but declares 112 mg elemental magnesium. Compare the 112 mg amount; do not add the two numbers. A blend total cannot establish an individual form’s share.
Magnesium glycinate vs citrate, oxide and threonate
NIH ODS reports that citrate and some other soluble forms tend to be absorbed more completely than oxide. Absorption findings do not establish one best treatment for sleep or anxiety.
The glycinate card explains the naming. The five US rows do not provide a direct retail comparison with threonate or oxide. An absent form should not be treated as a tested loser. Match the full serving and any additional active ingredients before comparing price.
Magnesium benefits: sleep, cramps and anxiety
Evidence by goal
Goal
Evidence strength
What was assessed
Typical study context
Main limitation
Sleep
Uncertain
Different preparations
Small or low-quality studies
No universal best form or bedtime dose
Night leg cramps
Generally little short-course benefit
Different preparations
Clinical reviews; some conflicting longer findings
Not proof that every cramp is a deficiency
Constipation
A distinct medicinal use
Magnesium citrate
Laxative directions
Not the same as routine nutrition support
Anxiety or brain performance
No ranking established here
No product-specific proof
Claims need separate clinical evidence
A form name or nutrient role is insufficient
Read the full evidence-by-goal detail
Sleep
NCCIH finds insufficient rigorous evidence to establish magnesium for sleep disorders. This includes popular “sleepy girl mocktail” claims; a bedtime drink is not a validated treatment.
Cramps
American Family Physician finds little support for short courses for night cramps, with limited conflicting longer-course evidence. Pregnancy and unexplained cramps require their own context.
Constipation is a different question
MedlinePlus describes magnesium citrate as a saline laxative, including use before procedures. Its drug instructions should not be generalized to the nutritional supplements above.
When to take magnesium: morning or before bed?
The sleep evidence does not establish one ideal number of minutes before bed. Choose a practical schedule consistent with the label and medication-spacing advice. A form’s marketing name does not determine its best time of day.
Follow the correct instructions
Read capsule, powder and medicinal-liquid directions separately. Measure the complete serving and avoid substituting one scoop or capful from a different product.
Do not stack bedtime products blindly
Check magnesium already present in multivitamins, electrolyte mixes, antacids and laxatives. Include those sources when discussing total supplemental intake with a clinician.
Magnesium side effects and safe-dose context
Who should be cautious?If any of the following apply to you, speak to a healthcare professional before taking Magnesium - see the full detail below for why.
Kidney disease or reduced kidney function
Medicines that interact with magnesium or affect its level
Pregnancy, persistent bowel symptoms or a clinician-directed high-dose regimen
NIH ODS describes diarrhea, nausea and abdominal cramping with high supplemental intakes. Extremely high amounts can have serious effects; impaired kidney function increases concern about magnesium accumulation. A lower dose may still cause symptoms, and a green comparison pill is not a safety certificate.
For laxative use, MedlinePlus advises medical attention to persistent bowel changes and kidney disease. Do not use this table to design bowel preparation or treat repeated unexplained symptoms.
Magnesium interactions, vitamin D and zinc
NIH ODS identifies interactions with tetracycline/quinolone antibiotics and oral bisphosphonates; diuretics and proton-pump inhibitors can affect magnesium status. Ask a pharmacist for spacing specific to your medicine.
Vitamin D, zinc or B6 in a combination is an additional ingredient to assess, not an automatic benefit. Include duplicates from other products. The comparison records disclosed amounts and does not assume an unspecified blend provides a useful dose.
Magnesium foods and who may need more attention
NIH ODS identifies nuts, seeds, legumes, whole grains and leafy greens as useful food sources. Older adults, people with gastrointestinal disease or type 2 diabetes, and those with long-term alcohol dependence can be at greater risk of inadequate status.
Low food intake, a blood-test abnormality and symptoms such as poor sleep are different starting points. Review the likely cause instead of assuming a high-dose supplement is the answer. This is an adult comparison; children’s needs and limits differ.
How we assess magnesium quality
Testing review pending means the detailed product evidence review is unfinished. While testing is pending, it is excluded and the score is provisional. It does not mean a product failed testing or that no evidence exists.
FDA does not approve supplements for safety and effectiveness before sale. Check the exact product and lot behind a quality claim.
A useful report identifies the product, batch, laboratory, date, methods and results. Ingredient identity, measured content and contaminant testing answer different questions. A raw-material certificate is not automatically evidence for the bottle you buy. See how we verify testing.
For magnesium, verify the elemental amount and serving size, each named salt in a blend, and any additional active ingredients. A certificate showing compound weight alone cannot establish the elemental dose on the label.
Magnesium deficiency and blood testing
MedlinePlus explains that blood magnesium can be normal despite low body stores. Results need medical history and other tests; they are not a direct measurement of every tissue.
Use your laboratory’s report
US reports may use mg/dL or mmol/L. Read the reported unit and interval together. Do not compare a number to a range copied from another unit system.
A result does not pick a form
An abnormal result cannot tell you which retail glycinate or citrate product to buy. Discuss kidney function, medicines and the possible cause with your clinician; do not infer a dose from symptoms alone.
Testing evidence in this comparison
A testing claim is not the same as a verified report. No public evidence located does not mean a product has not been tested.
Testing review pending0
Recognised certification0
Verified independent evidence1
Manufacturer COA0
Testing claimed8
No public evidence located7
What does magnesium cost?
Current US comparison set, based on the daily serving shown on each label.
$0.06Lowest daily cost
$0.26Median daily cost
$1.31Highest daily cost
Your questions, answered
Is glycinate better than citrate for sleep?
The available US evidence summaries do not establish a universal winner. See sleep evidence.
Is 400 mg magnesium safe every day?
The US adult upper limit from supplements and medications is 350 mg/day. A 400 mg product exceeds it even if the table badge shows a common range. See dose context.
Why does a 500 mg product provide less magnesium?
The headline may be compound weight. Use elemental magnesium in Supplement Facts; see label arithmetic.
Can I use citrate for constipation?
Medicinal citrate has separate instructions and cautions. Read the laxative distinction and the actual drug label.
