Magnesium compared by form
One product per form, plus one certified for sport: 6 products side by side on elemental magnesium per serving, the testing each label names and the price per 100 mg of elemental magnesium. L-threonate costs the most per mg: $0.72 per 100 mg, against $0.10 to $0.28 for glycinate, citrate and malate.
Prices checked Oct 24, 2026 6 products Magnesium: the evidence
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Not a ranking and not a recommendation. Ask your pharmacist or clinician before adding magnesium, especially with kidney disease or prescription medicines.
By form
Prices are one-time prices at the size shown, per 100 mg of elemental magnesium (the magnesium itself, not the salt).
Magnesium by form
Checked Oct 24, 2026| Form | Product | Elemental Mg per serving | Testing on the label | Per 100 mg | Source |
|---|---|---|---|---|---|
| Glycinate (bisglycinate) | Nature Made High Absorption Magnesium Glycinate 200 mg Lowest price per mg among this form’s products that name third-party testing. | 200 mg in 2 capsules | USP Verified | $0.20 per 100 mg$34.75 for 180 capsules · checked Oct 24, 2026 | Read on amazon.com |
| Citrate | NOW Foods Magnesium Citrate veg capsules Lowest price per mg of this form (none names third-party testing). | 400 mg in 3 capsules Above the 350 mg/day upper limit for supplemental magnesium. | None named | $0.12 per 100 mg$37.99 for 240 capsules · checked Oct 10, 2026 | Read on nowfoods.com |
| Oxide | Life Extension Magnesium Caps 500 mg Lowest price per mg of this form (none names third-party testing). | 500 mg in 1 capsule Above the 350 mg/day upper limit for supplemental magnesium. | None named | $0.02 per 100 mg$9.00 for 100 capsules · checked Oct 24, 2026 | Read on lifeextension.com |
| L-threonate | Double Wood Magnesium L-Threonate Lowest price per mg among this form’s products that name third-party testing. | 144 mg in 4 capsules | NSF Contents Certified (NSF/ANSI 173) | $0.72 per 100 mg$30.95 for 120 capsules · checked Oct 24, 2026 | Read on doublewoodsupplements.com |
| Malate | Source Naturals Magnesium Malate 1250 mg tablets Lowest price per mg of this form (none names third-party testing). | 425 mg in 3 tablets Above the 350 mg/day upper limit for supplemental magnesium. | None named | $0.10 per 100 mg$51.98 for 360 tablets · checked Oct 24, 2026 | Read on sourcenaturals.com |
| Certified for sport (glycinate) | Momentous Magnesium Bisglycinate Lowest price per mg certified for sport (NSF Certified for Sport or Informed Sport), for drug-tested athletes. | 200 mg in 2 capsules | NSF Certified for Sport | $0.28 per 100 mg$16.99 for 60 capsules · checked Oct 24, 2026 | Read on livemomentous.com (paid link, opens in new tab) Paid link |
How we chose
The rule
Applied to the price index- For each form, the product with the lowest price per mg of elemental magnesium among those whose label names third-party testing. Where no product of a form names testing, the lowest price per mg of that form.
- One more row for drug-tested athletes: the lowest price per mg among products certified for sport (NSF Certified for Sport or Informed Sport), only when the certification is on record for that product. Momentous comes in on this criterion, not because it pays us.
- The prices are the ones on our price per effective dose index, re-checked there. Who pays us does not change which product a rule picks. A product link pays us only when the brand is an active partner, and then it says so.
Dose against the studied range and the upper limit
What the magnesium page records
NIH and the trials it cites- Adult RDA 310–420 mg/day from all sources (by age and sex). Upper limit for supplemental magnesium: 350 mg/day for adults.
- The upper limit covers supplements and medicines only, not magnesium in food.
- Doses studied in human trials ranged from about 82 to 973 mg/day of elemental magnesium: 82 to 637 mg/day (median 365 mg) for at least 4 weeks in a 2025 pooled analysis of 38 blood-pressure trials, and about 243 to 973 mg/day for 8 to 26 weeks in the Cochrane blood-pressure review cited by NIH ODS. Many of these exceed the 350 mg/day upper limit for supplements.
- A serving above 350 mg is flagged in the table: the upper limit is a ceiling for supplements, not a target.
Each form’s absorption and tolerance, with sources, is on the magnesium page.
These statements have not been evaluated by the FDA. These products are not intended to diagnose, treat, cure, or prevent any disease.
Questions
Common questions
Which magnesium form is best?
This page does not pick one. It shows one product per form under a stated rule (lowest price per mg of elemental magnesium among products whose label names third-party testing) so the forms can be compared on price and dose. What each form has been studied for, and how strong that evidence is, is on our magnesium page.
Why does magnesium L-threonate cost more?
Per mg of elemental magnesium it is the most expensive form here: $0.72 per 100 mg for Double Wood, against $0.02 for the lowest-priced row (oxide). Magnesium L-threonate is 8.3% elemental magnesium by weight, against 14.1% for glycinate and 16.2% for citrate, so more of what you pay for is the threonate part of the compound.
Is a serving above the upper limit unsafe?
The 350 mg upper limit covers magnesium from supplements and medicines, not food. It is a ceiling, not a target. 3 of these products give more than that in one labelled serving; the table flags them. People with kidney disease should not take magnesium without their clinician.
Does Kymata earn money from these links?
When the brand is an active partner, yes: its link is marked and pays us a commission. Other rows link the seller plainly and pay us nothing. Which product a rule picks does not change with who pays us.