Same elemental magnesium · two salts · snapshot 2026-08-10
Magnesium gluconate vs hydroxide: 3,413 vs 480 mg of compound for 200 mg of magnesium
Magnesium gluconate is 5.9% elemental magnesium and magnesium hydroxide is 41.7%, so 200 mg of magnesium needs 3,413 mg of gluconate against 480 mg of hydroxide: 5 vs 1 size 00 capsules at powder density 0.8 g/mL, the top of the usual 0.6–0.8 range. 0 of 2 capsule labels naming gluconate alone are above the assumed size 000 capacity at powder density 0.8 g/mL, against none for hydroxide (no capsule label names it alone). Prices within each salt: gluconate $0.6164 per 100 mg (a single ranked offer); no ranked hydroxide price; observed 2026-10-26 to 2026-11-02.
computed from chemical formulas
Chart data
| Displayed chart text |
|---|
| 100 mg magnesium |
| hydroxide 240 · gluconate 1,706 |
| 200 mg magnesium |
| hydroxide 480 · gluconate 3,413 |
| 400 mg magnesium |
| hydroxide 960 · gluconate 6,826 |
Data release 2026-08-10-f441aa9f · registry snapshot 2026-08-10 · latest price observation 2026-11-02 · chemistry 2026-10-17
How much gluconate or hydroxide carries the same elemental magnesium?
At the same elemental amount, hydroxide (41.7% magnesium) always needs less compound than gluconate (5.9%): for 400 mg of magnesium, 960 mg against 6,826 mg. That is the mass of powder per dose; how much of it is absorbed is what the studies below measured.
computed| Elemental magnesium | gluconate compound | gluconate size 00 | hydroxide compound | hydroxide size 00 |
|---|---|---|---|---|
| 100 mg | 1,706 mg | 3 | 240 mg | 1 |
| 200 mg | 3,413 mg | 5 | 480 mg | 1 |
| 400 mg | 6,826 mg | 10 | 960 mg | 2 |
Source · Chemical formulas and NIH DSLD labels · snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
Estimated salt mass versus assumed capsule capacity
0 of 2 capsule labels naming gluconate alone are above the assumed size 000 capacity at powder density 0.8 g/mL, against none for hydroxide (no capsule label names it alone). Verdicts use the most favourable hydration and the most units per serving at powder density 0.8 g/mL, the top of the usual 0.6–0.8 range; the audited registry as a whole has 8 of 137 capsule labels above size 000.
computed with assumption| Salt | Audited capsule labels | Fits 0 or 00 | Needs 000 | Exceeds 000 |
|---|---|---|---|---|
| gluconate | 2 | 2 | 0 | 0 |
| hydroxide | 0 | 0 | 0 | 0 |
Source · NIH DSLD labels; mass balance · recognized salt only; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
What does each cost per 100 mg of elemental magnesium, within its own salt?
Compared only with offers of the same salt: gluconate $0.6164 per 100 mg (a single ranked offer); no ranked hydroxide price. Prices observed 2026-10-26 to 2026-11-02; a ranking exists only inside one salt, because the compound mass per 100 mg of magnesium differs between salts.
computed| Salt | Ranked offers | Lowest per 100 mg | Median per 100 mg | Observed |
|---|---|---|---|---|
| gluconate | 1 | $0.6164 | $0.6164 | 2026-11-02 |
| hydroxide | 0 | none | none | 2026-11-02 |
Source · Amazon via licensed data provider; NIH DSLD · unique ASIN × date; prices observed 2026-10-26 to 2026-11-02 · release 2026-08-10-f441aa9f · CSV · method
Has any study measured gluconate and hydroxide side by side?
No study in the PubMed-checked registry measured gluconate and hydroxide side by side as of 2026-08-10; 2 involve gluconate and 1 involve hydroxide separately.
measured| Year | Study | Salts measured | PubMed |
|---|---|---|---|
| 2005 | Study of magnesium bioavailability from ten organic and inorganic Mg salts in Mg-depleted rats using a stable isotope approach | oxide, chloride, sulfate, carbonate, citrate, gluconate, lactate, aspartate, glycinate | 16548135 |
| 1992 | Blood and urinary magnesium kinetics after oral magnesium supplements. | chloride, gluconate | 1468087 |
| 2025 | Comparing the Bioavailability of Two Seawater-Derived Magnesium Preparations. | citrate, hydroxide | 40955524 |
Source · PubMed-checked study registry · registry checked 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
How many labels name both gluconate and hydroxide?
No label names both gluconate and hydroxide as of 2026-08-10, against 20 labels naming gluconate and 10 naming hydroxide.
measured| Label | Declared elemental per serving | NIH DSLD |
|---|---|---|
| No label as of 2026-08-10 |
Source · Chemical formulas and NIH DSLD labels · snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
What does every dose from 25 to 1,000 mg of magnesium need in each salt?
The table converts 40 elemental amounts, 25 to 1,000 mg in 25 mg steps, into compound mass and size 00 capsules for both salts, against 730 mg per size 00 capsule at powder density 0.8 g/mL, the top of the usual 0.6–0.8 range. The first eight rows are shown; the rest open below.
computed| Elemental magnesium | gluconate compound | gluconate size 00 | hydroxide compound | hydroxide size 00 |
|---|---|---|---|---|
| 25 mg | 427 mg | 1 | 60 mg | 1 |
| 50 mg | 853 mg | 2 | 120 mg | 1 |
| 75 mg | 1,280 mg | 2 | 180 mg | 1 |
| 100 mg | 1,706 mg | 3 | 240 mg | 1 |
| 125 mg | 2,133 mg | 3 | 300 mg | 1 |
| 150 mg | 2,560 mg | 4 | 360 mg | 1 |
| 175 mg | 2,986 mg | 5 | 420 mg | 1 |
| 200 mg | 3,413 mg | 5 | 480 mg | 1 |
32 additional rows
| Elemental magnesium | gluconate compound | gluconate size 00 | hydroxide compound | hydroxide size 00 |
|---|---|---|---|---|
| 225 mg | 3,840 mg | 6 | 540 mg | 1 |
| 250 mg | 4,266 mg | 6 | 600 mg | 1 |
| 275 mg | 4,693 mg | 7 | 660 mg | 1 |
| 300 mg | 5,119 mg | 8 | 720 mg | 1 |
| 325 mg | 5,546 mg | 8 | 780 mg | 2 |
| 350 mg | 5,973 mg | 9 | 840 mg | 2 |
| 375 mg | 6,399 mg | 9 | 900 mg | 2 |
| 400 mg | 6,826 mg | 10 | 960 mg | 2 |
| 425 mg | 7,253 mg | 10 | 1,020 mg | 2 |
| 450 mg | 7,679 mg | 11 | 1,080 mg | 2 |
| 475 mg | 8,106 mg | 12 | 1,140 mg | 2 |
| 500 mg | 8,532 mg | 12 | 1,200 mg | 2 |
| 525 mg | 8,959 mg | 13 | 1,260 mg | 2 |
| 550 mg | 9,386 mg | 13 | 1,320 mg | 2 |
| 575 mg | 9,812 mg | 14 | 1,380 mg | 2 |
| 600 mg | 10,239 mg | 15 | 1,440 mg | 2 |
| 625 mg | 10,666 mg | 15 | 1,500 mg | 3 |
| 650 mg | 11,092 mg | 16 | 1,560 mg | 3 |
| 675 mg | 11,519 mg | 16 | 1,619 mg | 3 |
| 700 mg | 11,945 mg | 17 | 1,679 mg | 3 |
| 725 mg | 12,372 mg | 17 | 1,739 mg | 3 |
| 750 mg | 12,799 mg | 18 | 1,799 mg | 3 |
| 775 mg | 13,225 mg | 19 | 1,859 mg | 3 |
| 800 mg | 13,652 mg | 19 | 1,919 mg | 3 |
| 825 mg | 14,078 mg | 20 | 1,979 mg | 3 |
| 850 mg | 14,505 mg | 20 | 2,039 mg | 3 |
| 875 mg | 14,932 mg | 21 | 2,099 mg | 3 |
| 900 mg | 15,358 mg | 22 | 2,159 mg | 3 |
| 925 mg | 15,785 mg | 22 | 2,219 mg | 4 |
| 950 mg | 16,212 mg | 23 | 2,279 mg | 4 |
| 975 mg | 16,638 mg | 23 | 2,339 mg | 4 |
| 1,000 mg | 17,065 mg | 24 | 2,399 mg | 4 |
Source · Chemical formulas and NIH DSLD labels · snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method