Magnesium: which type?
We compare magnesium in 6 salts, 5 of them in more than one format. Salts are not interchangeable: each carries a different amount of actual magnesium per gram, and the review the cheapest-per-dose page cites found they are not all absorbed equally well. So each type is compared on its own, and every price below is per 200 mg of elemental magnesium, not per capsule and not per bottle.
The choice of type matters more than the choice of brand within it. Comparing capsules with capsules, the spread across types is 51×, against far less within any one of them. Read that as a reason to choose the type deliberately, not as a reason to buy the cheapest one. The L-Threonate capsule figure is a last known price, from Oct 17, 2026.
Of the 94 products across every type: 13 confirmed at the exact package by a certifier, 7 at another size only, 3 whose listing names another form only, 71 in no database we searched.
The salt that carries the most magnesium per gram of compound, and the only inorganic one here. A review the cheapest-per-dose page cites found inorganic forms appear less bioavailable than organic ones. Price per dose flatters it, and that is the point of showing it.
The number on the front of a magnesium bottle is usually the weight of the compound, not the magnesium in it, and some products sold as glycinate name magnesium oxide on the panel as well. Priced on what the panel states.
Widely sold and cheap per elemental milligram. Compared on elemental magnesium, not on the weight of the citrate compound.
Compared on elemental magnesium. Labels commonly print the malate compound weight, which is several times the magnesium it carries.
Magnesium bound to taurine. Panels here state the magnesium itself, which is a small fraction of the compound weight the front of the bottle usually names.
The panels here state a compound weight many times the magnesium it carries, which is part of why it prices high per dose. What that buys is the question the note on it takes up.
The prices on these cards are for products whose panel names one salt. A product whose panel also names a second salt is a blend: it stays on its type's page, and is left out of these prices and counted under Blended below. Which products are blends.
What each type's market looks like
Which type suits you is a question about your body, and this site does not answer it. What it can describe is what is actually on sale in each, and what we were able to check, the things you would otherwise have to open thirty product pages to find out.
| Type | Cheapest capsule | Blended | Certified | Units | Brands |
|---|---|---|---|---|---|
| Oxide capsule, powder, softgel, tablet | $0.027 | 0/15 | 0/15 | 0.4 | 5 |
| Glycinate capsule, powder, softgel, sachet, gummy, tablet | $0.125 plus vitamin C 204 mg | 5/36 | 7/36 | 1.5 | 12 |
| Citrate capsule, powder, softgel, tablet, gummy | $0.133 | 0/20 | 5/20 | 2.0 | 8 |
| Malate capsule, powder | $0.143 | 4/10 | 0/10 | 1.4 | 5 |
| Taurate powder, capsule | $0.406 | 0/6 | 0/6 | 4.4 | 4 |
| L-Threonate capsule | $1.36 last known price, Oct 17, 2026 | 0/7 | 1/7 | 4.2 | 5 |
Blended counts products whose own Supplement Facts panel names a second salt, usually magnesium oxide, the cheapest source of elemental magnesium, out of the panels we have read in that type. On each of these the product name names one salt, and the panel names more.
Certified counts products confirmed at the exact package sold, out of those we searched certifier databases for: an NSF listing that names that package, or a USP directory entry for the product with the USP mark on that package's own label. A listing naming a different size or form is not counted, which is why this number is smaller than the number of products from certified brands.
Cheapest capsule and units per dose are for capsules, softgels and tablets whose panel names one salt: a powder is never priced against a capsule here, a blend is left out, and each type's own page ranks its powders separately. Units per dose is how many capsules of the cheapest one make one comparison dose. A cheap form that takes four capsules is a different daily proposition from one that takes half of one.
What this table cannot tell you is which form to take. It says nothing about absorption, tolerability or what any form is typically used for. The one absorption claim this site makes is about magnesium oxide. It carries published citations and lives on the cheapest-per-dose page.
Questions about magnesium
Cheapest means the cheapest we track, not the cheapest that exists, and a low cost per dose is a statement about price rather than about how well a form is absorbed, which we do not measure. How these numbers are made: How we compare.
What this rests on: prices we last recorded at the retailer named on each product page, which go stale, and each page says when it was checked; the products we track, not every product sold, and Amazon and Walmart are not among the stores; listings and labels read at the source, each linked from the page. Found an error? Tell us. The full method: How we compare.