Same elemental magnesium · two salts · snapshot 2026-08-10
Magnesium citrate vs sulfate: 1,238–1,770 vs 991–2,028 mg of compound for 200 mg of magnesium
Magnesium citrate is 11.3–16.2% elemental magnesium and magnesium sulfate is 9.9–20.2%, so 200 mg of magnesium needs 1,238–1,770 mg of citrate against 991–2,028 mg of sulfate: 2–3 vs 2–3 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 none for sulfate (no capsule label names it alone). Prices within each salt: citrate from $0.0344 per 100 mg (median $0.1159, 12 ranked offers); no ranked sulfate price; observed 2026-10-26 to 2026-11-02.
computed from chemical formulas
Chart data
| Displayed chart text |
|---|
| 100 mg magnesium |
| sulfate 495–1,014 · citrate 619–885 |
| 200 mg magnesium |
| sulfate 991–2,028 · citrate 1,238–1,770 |
| 400 mg magnesium |
| sulfate 1,981–4,057 · citrate 2,475–3,540 |
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 sulfate carries the same elemental magnesium?
At the same elemental amount, sulfate (9.9–20.2% magnesium) always needs less compound than citrate (11.3–16.2%): for 400 mg of magnesium, 1,981–4,057 mg against 2,475–3,540 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 | sulfate compound | sulfate size 00 |
|---|---|---|---|---|
| 100 mg | 619–885 mg | 1–2 | 495–1,014 mg | 1–2 |
| 200 mg | 1,238–1,770 mg | 2–3 | 991–2,028 mg | 2–3 |
| 400 mg | 2,475–3,540 mg | 4–5 | 1,981–4,057 mg | 3–6 |
citrate: trimagnesium dicitrate 16.2%; dibasic and hydrated forms as low as 11.3%; sulfate: anhydrous 20.2%, heptahydrate 9.9%; 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 none for sulfate (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 |
|---|---|---|---|---|
| citrate | 62 | 25 | 32 | 5 |
| sulfate | 0 | 0 | 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 sulfate 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); no ranked sulfate 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 |
|---|---|---|---|---|
| citrate | 12 | $0.0344 | $0.1159 | 2026-11-02 |
| sulfate | 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 citrate and sulfate side by side?
2 studies in the PubMed-checked registry measured both salts in the same design; 10 involve citrate and 2 involve sulfate in total. They measured outcomes of the salts, not of any label.
measured| Year | Study | Salts measured | PubMed |
|---|---|---|---|
| 2019 | Timeline (Bioavailability) of Magnesium Compounds in Hours: Which Magnesium Compound Works Best? | sulfate, oxide, taurate, citrate, malate | 29679349 |
| 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 |
| 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 |
2 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 |
Source · PubMed-checked study registry · registry checked 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
How many labels name both citrate and sulfate?
No label names both citrate and sulfate as of 2026-08-10, against 212 labels naming citrate and 4 naming sulfate.
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 | citrate compound | citrate size 00 | sulfate compound | sulfate size 00 |
|---|---|---|---|---|
| 25 mg | 155–221 mg | 1 | 124–254 mg | 1 |
| 50 mg | 309–442 mg | 1 | 248–507 mg | 1 |
| 75 mg | 464–664 mg | 1 | 371–761 mg | 1–2 |
| 100 mg | 619–885 mg | 1–2 | 495–1,014 mg | 1–2 |
| 125 mg | 774–1,106 mg | 2 | 619–1,268 mg | 1–2 |
| 150 mg | 928–1,327 mg | 2 | 743–1,521 mg | 2–3 |
| 175 mg | 1,083–1,549 mg | 2–3 | 867–1,775 mg | 2–3 |
| 200 mg | 1,238–1,770 mg | 2–3 | 991–2,028 mg | 2–3 |
32 additional rows
| Elemental magnesium | citrate compound | citrate size 00 | sulfate compound | sulfate size 00 |
|---|---|---|---|---|
| 225 mg | 1,392–1,991 mg | 2–3 | 1,114–2,282 mg | 2–4 |
| 250 mg | 1,547–2,212 mg | 3–4 | 1,238–2,535 mg | 2–4 |
| 275 mg | 1,702–2,434 mg | 3–4 | 1,362–2,789 mg | 2–4 |
| 300 mg | 1,856–2,655 mg | 3–4 | 1,486–3,043 mg | 3–5 |
| 325 mg | 2,011–2,876 mg | 3–4 | 1,610–3,296 mg | 3–5 |
| 350 mg | 2,166–3,097 mg | 3–5 | 1,734–3,550 mg | 3–5 |
| 375 mg | 2,321–3,319 mg | 4–5 | 1,857–3,803 mg | 3–6 |
| 400 mg | 2,475–3,540 mg | 4–5 | 1,981–4,057 mg | 3–6 |
| 425 mg | 2,630–3,761 mg | 4–6 | 2,105–4,310 mg | 3–6 |
| 450 mg | 2,785–3,982 mg | 4–6 | 2,229–4,564 mg | 4–7 |
| 475 mg | 2,939–4,204 mg | 5–6 | 2,353–4,817 mg | 4–7 |
| 500 mg | 3,094–4,425 mg | 5–7 | 2,476–5,071 mg | 4–7 |
| 525 mg | 3,249–4,646 mg | 5–7 | 2,600–5,325 mg | 4–8 |
| 550 mg | 3,403–4,867 mg | 5–7 | 2,724–5,578 mg | 4–8 |
| 575 mg | 3,558–5,088 mg | 5–7 | 2,848–5,832 mg | 4–8 |
| 600 mg | 3,713–5,310 mg | 6–8 | 2,972–6,085 mg | 5–9 |
| 625 mg | 3,868–5,531 mg | 6–8 | 3,096–6,339 mg | 5–9 |
| 650 mg | 4,022–5,752 mg | 6–8 | 3,219–6,592 mg | 5–10 |
| 675 mg | 4,177–5,973 mg | 6–9 | 3,343–6,846 mg | 5–10 |
| 700 mg | 4,332–6,195 mg | 6–9 | 3,467–7,099 mg | 5–10 |
| 725 mg | 4,486–6,416 mg | 7–9 | 3,591–7,353 mg | 5–11 |
| 750 mg | 4,641–6,637 mg | 7–10 | 3,715–7,606 mg | 6–11 |
| 775 mg | 4,796–6,858 mg | 7–10 | 3,839–7,860 mg | 6–11 |
| 800 mg | 4,950–7,080 mg | 7–10 | 3,962–8,114 mg | 6–12 |
| 825 mg | 5,105–7,301 mg | 7–11 | 4,086–8,367 mg | 6–12 |
| 850 mg | 5,260–7,522 mg | 8–11 | 4,210–8,621 mg | 6–12 |
| 875 mg | 5,415–7,743 mg | 8–11 | 4,334–8,874 mg | 6–13 |
| 900 mg | 5,569–7,965 mg | 8–11 | 4,458–9,128 mg | 7–13 |
| 925 mg | 5,724–8,186 mg | 8–12 | 4,581–9,381 mg | 7–13 |
| 950 mg | 5,879–8,407 mg | 9–12 | 4,705–9,635 mg | 7–14 |
| 975 mg | 6,033–8,628 mg | 9–12 | 4,829–9,888 mg | 7–14 |
| 1,000 mg | 6,188–8,850 mg | 9–13 | 4,953–10,142 mg | 7–14 |
Source · Chemical formulas and NIH DSLD labels · snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method