Same elemental magnesium · two salts · snapshot 2026-08-10
Magnesium citrate vs gluconate: 1,238–1,770 vs 3,413 mg of compound for 200 mg of magnesium
Magnesium citrate is 11.3–16.2% elemental magnesium and magnesium gluconate is 5.9%, so 200 mg of magnesium needs 1,238–1,770 mg of citrate against 3,413 mg of gluconate: 2–3 vs 5 size 00 capsules at powder density 0.8 g/mL, the top of the usual 0.6–0.8 range. 5 of 62 capsule labels naming citrate alone are above the assumed size 000 capacity at powder density 0.8 g/mL, against 0 of 2 for gluconate. Prices within each salt: citrate from $0.0344 per 100 mg (median $0.1159, 12 ranked offers); gluconate $0.6164 per 100 mg (a single ranked offer); observed 2026-10-26 to 2026-11-02.
computed from chemical formulas
Chart data
| Displayed chart text |
|---|
| 100 mg magnesium |
| citrate 619–885 · gluconate 1,706 |
| 200 mg magnesium |
| citrate 1,238–1,770 · gluconate 3,413 |
| 400 mg magnesium |
| citrate 2,475–3,540 · 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 citrate or gluconate carries the same elemental magnesium?
At the same elemental amount, citrate (11.3–16.2% magnesium) always needs less compound than gluconate (5.9%): for 400 mg of magnesium, 2,475–3,540 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 | citrate compound | citrate size 00 | gluconate compound | gluconate size 00 |
|---|---|---|---|---|
| 100 mg | 619–885 mg | 1–2 | 1,706 mg | 3 |
| 200 mg | 1,238–1,770 mg | 2–3 | 3,413 mg | 5 |
| 400 mg | 2,475–3,540 mg | 4–5 | 6,826 mg | 10 |
citrate: trimagnesium dicitrate 16.2%; dibasic and hydrated forms as low as 11.3%; hydration ambiguity stays a range.
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
5 of 62 capsule labels naming citrate alone are above the assumed size 000 capacity at powder density 0.8 g/mL, against 0 of 2 for gluconate. 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
Chart data
| Displayed chart text |
|---|
| citrate |
| fits 25 of 62 |
| needs 000 32 of 62 |
| exceeds 5 of 62 |
| gluconate |
| fits 2 of 2 |
| needs 000 0 of 2 |
| exceeds 0 of 2 |
| Salt | Audited capsule labels | Fits 0 or 00 | Needs 000 | Exceeds 000 |
|---|---|---|---|---|
| citrate | 62 | 25 | 32 | 5 |
| gluconate | 2 | 2 | 0 | 0 |
Source · NIH DSLD labels; mass balance · recognized salt only; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
Which citrate and gluconate labels are above the assumed size 000 capacity at powder density 0.8 g/mL?
5 of 62 citrate capsule labels declare more magnesium than the named salt alone can deliver from a size 000 capsule, at the most favourable hydration and units per serving; each row opens the label's own arithmetic.
computed with assumption| Label | Salt | Salt per capsule | Verdict |
|---|---|---|---|
| Vitamin World Magnesium Citrate 250 mg | citrate | 1,547 mg | exceeds size 000 |
| Biotech Nutritions Magnesium Citrate | citrate | 1,392 mg | exceeds size 000 |
| Nutricost Magnesium Citrate 420 mg | citrate | 1,300 mg | exceeds size 000 |
| Evlution Nutrition Magnesium Citrate 400 mg | citrate | 1,238 mg | exceeds size 000 |
| NuMedica Magnesium Citrate Extra Strength 200 mg | citrate | 1,238 mg | exceeds size 000 |
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: citrate from $0.0344 per 100 mg (median $0.1159, 12 ranked offers); gluconate $0.6164 per 100 mg (a single ranked offer). 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 |
|---|---|---|---|---|
| citrate | 12 | $0.0344 | $0.1159 | 2026-11-02 |
| gluconate | 1 | $0.6164 | $0.6164 | 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 citrate and gluconate side by side?
One study in the PubMed-checked registry measured both salts in the same design; 10 involve citrate and 2 involve gluconate in total. They measured outcomes of the salts, not of any label.
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 |
| 2025 | Comparing the Bioavailability of Two Seawater-Derived Magnesium Preparations. | citrate, hydroxide | 40955524 |
| 2024 | Comparative Clinical Study on Magnesium Absorption and Side Effects After Oral Intake of Microencapsulated Magnesium (MAGSHAPE™ Microcapsules) Versus Other Magnesium Sources. | citrate, glycinate, oxide | 39770988 |
| 2022 | Effects of short-term magnesium supplementation on ionized, total magnesium and other relevant electrolytes levels. | oxide, citrate, carbonate | 35041150 |
| 2020 | Dose-Dependent Absorption Profile of Different Magnesium Compounds | oxide, citrate, glycinate, malate | 30761462 |
| 2019 | Timeline (Bioavailability) of Magnesium Compounds in Hours: Which Magnesium Compound Works Best? | sulfate, oxide, taurate, citrate, malate | 29679349 |
| 2012 | Comparison of magnesium status using X-ray dispersion analysis following magnesium oxide and magnesium citrate treatment of healthy subjects | citrate, oxide | 22433473 |
| 2003 | Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study | citrate, oxide, glycinate | 14596323 |
3 additional rows
| Year | Study | Salts measured | PubMed |
|---|---|---|---|
| 1990 | Magnesium bioavailability from magnesium citrate and magnesium oxide | citrate, oxide | 2407766 |
| 1990 | Effect of magnesium citrate and magnesium oxide on the crystallization of calcium salts in urine | citrate, oxide | 2299712 |
| 1992 | Blood and urinary magnesium kinetics after oral magnesium supplements. | chloride, gluconate | 1468087 |
Source · PubMed-checked study registry · registry checked 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
How many labels name both citrate and gluconate?
1 of 212 labels naming citrate also name gluconate as of 2026-08-10; a named blend does not establish how much magnesium each salt contributes.
measured| Label | Declared elemental per serving | NIH DSLD |
|---|---|---|
| Roex Magnesium Potassium | 400 mg | 211503 |
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 | citrate compound | citrate size 00 | gluconate compound | gluconate size 00 |
|---|---|---|---|---|
| 25 mg | 155–221 mg | 1 | 427 mg | 1 |
| 50 mg | 309–442 mg | 1 | 853 mg | 2 |
| 75 mg | 464–664 mg | 1 | 1,280 mg | 2 |
| 100 mg | 619–885 mg | 1–2 | 1,706 mg | 3 |
| 125 mg | 774–1,106 mg | 2 | 2,133 mg | 3 |
| 150 mg | 928–1,327 mg | 2 | 2,560 mg | 4 |
| 175 mg | 1,083–1,549 mg | 2–3 | 2,986 mg | 5 |
| 200 mg | 1,238–1,770 mg | 2–3 | 3,413 mg | 5 |
32 additional rows
| Elemental magnesium | citrate compound | citrate size 00 | gluconate compound | gluconate size 00 |
|---|---|---|---|---|
| 225 mg | 1,392–1,991 mg | 2–3 | 3,840 mg | 6 |
| 250 mg | 1,547–2,212 mg | 3–4 | 4,266 mg | 6 |
| 275 mg | 1,702–2,434 mg | 3–4 | 4,693 mg | 7 |
| 300 mg | 1,856–2,655 mg | 3–4 | 5,119 mg | 8 |
| 325 mg | 2,011–2,876 mg | 3–4 | 5,546 mg | 8 |
| 350 mg | 2,166–3,097 mg | 3–5 | 5,973 mg | 9 |
| 375 mg | 2,321–3,319 mg | 4–5 | 6,399 mg | 9 |
| 400 mg | 2,475–3,540 mg | 4–5 | 6,826 mg | 10 |
| 425 mg | 2,630–3,761 mg | 4–6 | 7,253 mg | 10 |
| 450 mg | 2,785–3,982 mg | 4–6 | 7,679 mg | 11 |
| 475 mg | 2,939–4,204 mg | 5–6 | 8,106 mg | 12 |
| 500 mg | 3,094–4,425 mg | 5–7 | 8,532 mg | 12 |
| 525 mg | 3,249–4,646 mg | 5–7 | 8,959 mg | 13 |
| 550 mg | 3,403–4,867 mg | 5–7 | 9,386 mg | 13 |
| 575 mg | 3,558–5,088 mg | 5–7 | 9,812 mg | 14 |
| 600 mg | 3,713–5,310 mg | 6–8 | 10,239 mg | 15 |
| 625 mg | 3,868–5,531 mg | 6–8 | 10,666 mg | 15 |
| 650 mg | 4,022–5,752 mg | 6–8 | 11,092 mg | 16 |
| 675 mg | 4,177–5,973 mg | 6–9 | 11,519 mg | 16 |
| 700 mg | 4,332–6,195 mg | 6–9 | 11,945 mg | 17 |
| 725 mg | 4,486–6,416 mg | 7–9 | 12,372 mg | 17 |
| 750 mg | 4,641–6,637 mg | 7–10 | 12,799 mg | 18 |
| 775 mg | 4,796–6,858 mg | 7–10 | 13,225 mg | 19 |
| 800 mg | 4,950–7,080 mg | 7–10 | 13,652 mg | 19 |
| 825 mg | 5,105–7,301 mg | 7–11 | 14,078 mg | 20 |
| 850 mg | 5,260–7,522 mg | 8–11 | 14,505 mg | 20 |
| 875 mg | 5,415–7,743 mg | 8–11 | 14,932 mg | 21 |
| 900 mg | 5,569–7,965 mg | 8–11 | 15,358 mg | 22 |
| 925 mg | 5,724–8,186 mg | 8–12 | 15,785 mg | 22 |
| 950 mg | 5,879–8,407 mg | 9–12 | 16,212 mg | 23 |
| 975 mg | 6,033–8,628 mg | 9–12 | 16,638 mg | 23 |
| 1,000 mg | 6,188–8,850 mg | 9–13 | 17,065 mg | 24 |
Source · Chemical formulas and NIH DSLD labels · snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method