Magnesium price comparison: use elemental magnesium
Compare magnesium cost per gram using the elemental amount on Supplement Facts, while keeping citrate, glycinate and other forms distinct.
For a magnesium cost comparison, identify the amount on the Magnesium line of Supplement Facts. NIH ODS explains that this panel declares elemental magnesium, not the mass of the whole magnesium-containing compound. The form in parentheses is context worth retaining.
Read the amount and form together
A line such as “Magnesium (as magnesium citrate), 200 mg” describes 200 mg of declared elemental magnesium per label serving. It does not mean the whole serving weighs 200 mg. Do not replace that number with a larger compound weight printed elsewhere on a package.
Keep citrate, glycinate, oxide and other form names visible when comparing labels. Our arithmetic compares declared mass; it does not turn different forms into clinically equivalent products or establish an absorption-adjusted price.
Calculate a container, not a capsule
In a hypothetical example, a $18 container has 60 label servings at 150 mg elemental magnesium each. Total declared elemental magnesium is 9,000 mg, or 9 g. The ingredient cost is $18 ÷ 9 = $2.00 per gram, while the serving cost is $0.30.
If each serving is two capsules, the container needs 120 capsules to supply those 60 servings. Entering 120 as the serving count would halve the calculated cost incorrectly. Check the serving-size line before using the package count.
When the calculation should stop
Do not calculate individual form costs when one magnesium total is supplied by several forms with no separate amounts. A label may identify those forms without disclosing how the total is divided. Likewise, a blend weight is not a substitute for the magnesium declaration.
For the Form & Fact estimate, enter the current USD price, confirmed number of label servings, and elemental amount. The source observation may be older than the bottle you are buying, so check the current label first. The result is a budget comparison, not a dose or safety recommendation.
Explore magnesium reference labels · Open the cost calculator
Source and editorial scope
NIH ODS: magnesium, dietary supplements section ↗ · Consulted September 26, 2026. Examples and cost arithmetic are illustrative calculations by Form & Fact. Source attribution does not imply endorsement. No clinical review or product testing is claimed.
These guides explain labels and comparison arithmetic. They do not recommend an intake or establish a product's safety, efficacy or quality. Sources and methodology.