Label arithmetic · NIH DSLD 336416
Mason Natural Fast Absorption Magnesium Citrate 250 mg: 125 mg of magnesium per softgel, 2 softgels a day
125 mg of magnesium per softgel; the label's 2 softgels a day give 250 mg. Softgel fill is not modelled (Oct 17). Inside: label lines, ingredients.
Mason Natural Fast Absorption Magnesium Citrate 250 mg declares 250 mg of elemental magnesium per serving as citrate, which means 1,547–2,212 mg of magnesium citrate compound in one 2 softgel(s), compared with 1,100 mg in the largest standard capsule; capsule verdicts do not apply to this softgel capsule. No US retail price matched as of 2026-11-02; 17 of the 135 citrate labels in this registry have a matched price. NIH DSLD 336416, label dated 2025-08-22.
computed from the filed label
Chart data
| Displayed chart text |
|---|
| gluconate |
| 4,266 |
| orotate |
| 3,439 |
| L-threonate |
| 3,030 |
| taurate |
| 2,803 |
| lactate |
| 2,082 |
| glycerophosphate |
| 2,000 |
| glycinate |
| 1,773 |
| malate |
| 1,609 |
| aspartate |
| 1,598 |
| citrate |
| 1,547 |
| sulfate |
| 1,238 |
| chloride |
| 979 |
| carbonate |
| 867 |
| hydroxide |
| 600 |
| oxide |
| 414 |
Data release 2026-08-10-f441aa9f · registry snapshot 2026-08-10 · latest price observation 2026-10-19 · chemistry 2026-10-17
Mass: 774–1,106 mg per softgel · Price: none matched · % DV: 60% vs 60%
Elemental: The magnesium itself; the rest of the compound weight is the partner molecule.
Compound: The whole salt, such as magnesium glycinate, that must physically fit in the capsule.
Size 000: The largest standard capsule, about 1,100 mg of powder at 0.8 g/mL, the top of the usual 0.6–0.8 range; size 00 holds about 730 mg and size 0 about 545 mg.
Recompute with your price
Enter the price you paid; the declared amount and servings of this label are prefilled, so the result is the cost per 100 mg of elemental magnesium for your bottle.
Same-salt comparison appears here.
How much citrate compound is in one serving?
Mason Natural Fast Absorption Magnesium Citrate 250 mg carries 1,547–2,212 mg of magnesium citrate per serving for 250 mg of elemental magnesium, against 1,100 mg in the largest standard capsule; capsule capacities do not apply to this softgel capsule.
computed with assumption| Measure | Value |
|---|---|
| Elemental magnesium per serving | 250 mg |
| Units per serving | 2 |
| Magnesium citrate per serving | 1,547–2,212 mg |
| Magnesium citrate per softgel | 774–1,106 mg |
| Capsule capacity 0 · 00 · 000 | 545 · 730 · 1,100 mg |
| Verdict | Capsule sizes do not apply |
The filed salt can have more than one hydration state (trimagnesium dicitrate 16.2%; dibasic and hydrated forms as low as 11.3%), so the compound mass is a range.
Source · NIH DSLD 336416 · label 2025-08-22; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
How much elemental magnesium is actually in this label's filed magnesium lines?
Mason Natural Fast Absorption Magnesium Citrate 250 mg files 1 magnesium line in NIH DSLD 336416; the selected primary line declares 250 mg of elemental magnesium per serving, against 0 other rows excluded from the primary amount. A salt named under another nutrient does not turn that nutrient's quantity into elemental magnesium.
measured| Filed amount | Salt or note as filed | Role |
|---|---|---|
| 250 mg | Salt not named in this row; magnesium citrate is taken from the label text | Primary serving |
Source · NIH DSLD 336416 · label 2025-08-22; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
Does this label's citrate claim hold up, or could the magnesium come from another source?
The label names one magnesium form, citrate, resolved from the full NIH DSLD record text; capsule capacities do not apply to this form, compared with oxide, the salt richest in magnesium at 60.3%.
computed with assumption| Form named on the label | Elemental fraction | Source |
|---|---|---|
| Magnesium citrate | 11.3–16.2% | full NIH DSLD record text |
Source · NIH DSLD 336416 · label 2025-08-22; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
Is this a good price for the elemental magnesium I'm actually getting?
No US retail price is matched to this label as of 2026-11-02; 17 of 135 citrate labels have one, against a median of $0.1159 per 100 mg among 12 ranked citrate offers.
computed
Chart data
| Displayed chart text |
|---|
| n=12 |
| P25 $0.0843 |
| P75 $0.1469 |
| median $0.1159 |
| Rank | Label | Per 100 mg | Observed |
|---|---|---|---|
| 1 | Best Naturals Magnesium Citrate 200 mg | $0.0344 | 2026-11-02 |
| 2 | Solgar Magnesium Citrate | $0.0607 | 2026-11-02 |
| 3 | LES Labs Magnesium Citrate | $0.0777 | 2026-11-02 |
| 4 | Bluebonnet Magnesium Citrate | $0.0865 | 2026-11-02 |
| 5 | Solaray Magnesium Citrate 400 mg | $0.0868 | 2026-11-02 |
| Median | 12 ranked citrate offers | $0.1159 | 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
How many days will this bottle last at the label's own serving, and what does a day cost?
At the label's own serving, Mason Natural Fast Absorption Magnesium Citrate 250 mg lasts 30 days: 30 servings against 1 serving a day in the filed directions.
computed| Measure | Value |
|---|---|
| Net contents as filed | 60 Softgel(s) |
| Serving size as filed | 2 Softgel(s) |
| Servings per container | 30 |
| Servings per day in the directions | 1 |
| Days per bottle | 30 days |
| $ per 30 days at one label serving a day | No ranked price as of 2026-11-02 |
| $ per 30 days at 420 mg Daily Value | No ranked price as of 2026-11-02 |
Source · NIH DSLD 336416 · label 2025-08-22; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
What does "60% Daily Value" mean here, and does it recompute?
The label declares 60% Daily Value; 250 mg against the 420 mg reference in 21 CFR 101.9 recomputes to 60%, the same within one point.
computed| Group as filed | Declared | Reference | Recomputed |
|---|---|---|---|
| Adults and children 4 or more years of age | 60% | 420 mg | 60% |
Source · NIH DSLD 336416; 21 CFR 101.9 · label 2025-08-22 · release 2026-08-10-f441aa9f · CSV · method
Why does this label contain these other ingredients, what shell is it, and who is it filed for?
Mason Natural Fast Absorption Magnesium Citrate 250 mg files 9 other ingredients and a gelatin shell, and no magnesium stearate, against 43 of 135 citrate labels that list magnesium stearate.
measured| Entry | Filed ingredient or declaration |
|---|---|
| 1 | Safflower Oil |
| 2 | Bovine Gelatin |
| 3 | Glycerin |
| 4 | Water, Purified |
| 5 | yellow Beeswax |
| 6 | Sunflower Lecithin |
| 7 | Titanium Dioxide |
| 8 | Carmine |
3 additional rows
| Entry | Filed ingredient or declaration |
|---|---|
| 9 | Elderberry Extract |
| Shell | gelatin |
| Target group | Adult (18 - 50 Years) |
Source · NIH DSLD 336416 · label 2025-08-22; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
What has research measured about citrate, and about side effects?
10 studies in the PubMed-checked registry measured outcomes involving citrate; 1 mention gastrointestinal or adverse outcomes. They measured the salt, not this label.
measured| Year | Study | PubMed |
|---|---|---|
| 2025 | Comparing the Bioavailability of Two Seawater-Derived Magnesium Preparations. | 40955524 |
| 2024 | Comparative Clinical Study on Magnesium Absorption and Side Effects After Oral Intake of Microencapsulated Magnesium (MAGSHAPE™ Microcapsules) Versus Other Magnesium Sources. | 39770988 |
| 2022 | Effects of short-term magnesium supplementation on ionized, total magnesium and other relevant electrolytes levels. | 35041150 |
Source · PubMed-checked study registry · registry checked 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
Has this brand had FDA recalls or adverse event reports?
Mason Natural has 0 FDA recall records matched by brand name in the enforcement data queried 2026-10-19. Mason Natural has FDA CAERS adverse event reports on record at brand level, as do 143 of 273 brands in this registry; openFDA states that “there is no certainty that the reported event (adverse event) was actually due to the product” and that reports “cannot be used to estimate the incidence of these events.”
measured| Recall | Date | Reason | Status |
|---|---|---|---|
| No recall record as of 2026-10-19 |
Source · openFDA enforcement and CAERS · queried 2026-10-19 · release 2026-08-10-f441aa9f · CSV · method
Is this the same formula as another brand's, and how do their prices differ?
No other brand files the same formulation (ingredients, shell, units and rounded amount) as of 2026-11-02.
computed| Label | Brand | Price per 100 mg |
|---|---|---|
| No cross-brand match as of 2026-11-02 |
Source · NIH DSLD 336416 · label 2025-08-22; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
Which labels are closest to this one, with the same salt and dose?
6 labels use the same resolved citrate within ±10% of this label's 125 mg per unit, compared side by side on price and capsule verdict.
computed| Label | Elemental per unit | Price | Verdict |
|---|---|---|---|
| Nature Made Magnesium Citrate (DSLD 179947) | 125 mg | $10.89 · 2026-11-02 | Capsule sizes do not apply |
| Nature Made Magnesium Citrate (DSLD 179948) | 125 mg | $10.89 · 2026-11-02 | Capsule sizes do not apply |
| Meijer Magnesium Citrate 250 mg | 125 mg | No price | Capsule sizes do not apply |
| KAL Malic Acid 1500 mg with Magnesium | 125 mg | No price | Capsule sizes do not apply |
| Nature Made Magnesium Citrate 250 mg (DSLD 270965) | 125 mg | No price | Capsule sizes do not apply |
| Nature Made Magnesium Citrate 250 mg (DSLD 279878) | 125 mg | No price | Capsule sizes do not apply |
Source · NIH DSLD 336416 · label 2025-08-22; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
Where does this record come from, what is missing, and how do I cite or correct it?
Every value on this page traces to NIH DSLD 336416 (label 2025-08-22, snapshot 2026-08-10) and the chemistry model of 2026-09-13. 2 gaps remain: Capacity audit excluded as of 2026-10-17: softgel volume is not modelled by hard capsule sizes 0/00/000.; No US retail price matched as of 2026-11-02 (barcode 3 11845 18615 7). The CSV carries the values shown here.
measured| Field | As filed |
|---|---|
| NIH DSLD label | NIH DSLD 336416 |
| Scanned label (PDF) | Label 336416 scan |
| Label date | 2025-08-22 |
| Date entered into DSLD | 2025-08-22 |
| Barcode (UPC) as filed | 3 11845 18615 7 |
| Manufactured in the USA for | Mason Vitamins, Inc., Miami Lakes, FL |
| Claim category as filed | Nutrient |
| Claim category as filed | All Other |
19 additional rows
| Field | As filed |
|---|---|
| Claim category as filed | Structure/Function |
| Seals/Symbols | Mason Guarantee Laboratory Tested cGMP Certified Good Manufacturing Practice Certified |
| General Statements: All Other Content | N |
| Brand IP Statement(s) re: (c), (TM), (SM) | Mason Natural Est. 1967 |
| Formula re: Contains | Fast Absorption Magnesium Citrate 250 mg per serving |
| Formulation re: Other | Muscle relaxation, nerve & heart health |
| FDA Statement of Identity | Dietary Supplement |
| Suggested/Recommended/Usage/Directions | Directions: Adults - Take two softgels daily, preferably with food, as a dietary supplement. |
| Formulation re: Does NOT Contain | Guaranteed no added: milk, egg, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans, sesame. |
| FDA Disclaimer Statement | This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. |
| Precautions re: Pregnant or Nursing or Prescription Medications | Caution: If you are pregnant, nursing, taking any medications or have any medical condition, consult your physician before use. |
| Precautions re: All Other | Discontinue use and consult your physician if any adverse reactions occur. Tamper-evident seal: Do not use product if seal appears tampered with. |
| Precautions re: Children | Keep out of reach of children. |
| Formulation re: Does NOT Contain | Soy free |
| Storage | Store in a dry place under controlled room temperature: 20 degrees - 25 degrees C (68 degrees - 77 degrees F). |
| Brand IP Statement(s) re: (c), (TM), (SM) | Mason Natural is a registered trademark and does not refer to any product or ingredient claim. |
| General Statements: All Other Content | Please recycle |
| Physical state | Softgel Capsule |
| Registry snapshot | 2026-08-10 |
Source · NIH DSLD 336416 · label 2025-08-22; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
6 brand pages linked below contain magnesium labels from the NIH DSLD registry snapshot dated 2026-08-10.