Label arithmetic · NIH DSLD 313576
NOW Magnesium Citrate: 400 mg of magnesium per capsule, 3 capsules a day
400 mg of magnesium per capsule; the label's 3 capsules a day give 1,200 mg. No US price matched (Nov 2). Inside: salt weight, capsule size.
NOW Magnesium Citrate declares 400 mg of elemental magnesium per serving as citrate, which needs 2,475–3,540 mg of magnesium citrate in each capsule, against 1,100 mg in the largest standard capsule (size 000) at powder density 0.8 g/mL, the top of the usual 0.6–0.8 range: it fits only that size. 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 313576, label dated 2024-10-24.
computed from the filed label
Chart data
| Displayed chart text |
|---|
| 545 mg |
| 730 mg |
| 1,100 mg |
| 2,475–3,540 mg of citrate per capsule |
Data release 2026-08-10-f441aa9f · registry snapshot 2026-08-10 · latest price observation 2026-10-19 · chemistry 2026-10-17
Mass: 2,475–3,540 mg per capsule · Price: none matched · % DV: 95% vs 95%
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.
Will 400 mg of citrate actually fit in one capsule, or do I need more than one?
Estimated salt mass versus assumed capsule capacity: NOW Magnesium Citrate implies 2,475–3,540 mg of magnesium citrate in each capsule to deliver 400 mg of elemental magnesium, against 1,100 mg in the largest standard capsule (size 000) at powder density 0.8 g/mL, the top of the usual 0.6–0.8 range. Verdict: needs size 000, read at the most favourable hydration and the most units per serving. The label's 120 capsules over 40 servings imply 3 per serving, so that number is used.
computed with assumption| Measure | Value |
|---|---|
| Elemental magnesium per serving | 400 mg |
| Units per serving | 1 |
| Magnesium citrate per serving | 2,475–3,540 mg |
| Magnesium citrate per capsule | 2,475–3,540 mg |
| Capsule capacity 0 · 00 · 000 | 545 · 730 · 1,100 mg |
| Verdict | Needs size 000 |
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 313576 · label 2024-10-24; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
How much elemental magnesium is actually in this label's filed magnesium lines?
NOW Magnesium Citrate files 1 magnesium line in NIH DSLD 313576; the selected primary line declares 400 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 |
|---|---|---|
| 400 mg | elemental, from | Primary serving |
Source · NIH DSLD 313576 · label 2024-10-24; 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; at that salt the declaration is within the assumed size 000 capacity at powder density 0.8 g/mL, 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 313576 · label 2024-10-24; 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, NOW Magnesium Citrate lasts 13 days: 40 servings against 3 servings a day in the filed directions.
computed| Measure | Value |
|---|---|
| Net contents as filed | 120 Veg Capsule(s) |
| Serving size as filed | 1 Veg Capsule(s) |
| Servings per container | 40 |
| Servings per day in the directions | 3 |
| Days per bottle | 13 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 313576 · label 2024-10-24; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
What does "95% Daily Value" mean here, and does it recompute?
The label declares 95% Daily Value; 400 mg against the 420 mg reference in 21 CFR 101.9 recomputes to 95%, the same within one point.
computed| Group as filed | Declared | Reference | Recomputed |
|---|---|---|---|
| Adults and children 4 or more years of age | 95% | 420 mg | 95% |
Source · NIH DSLD 313576; 21 CFR 101.9 · label 2024-10-24 · 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?
NOW Magnesium Citrate files 3 other ingredients and a vegetarian shell, and no magnesium stearate, against 43 of 135 citrate labels that list magnesium stearate.
measured| Entry | Filed ingredient or declaration |
|---|---|
| 1 | Hypromellose |
| 2 | Ascorbyl Palmitate |
| 3 | Silicon Dioxide |
| Shell | vegetarian |
| Target group | Vegan |
| Target group | Vegetarian |
| Target group | Adult (18 - 50 Years) |
| Target group | Kosher |
3 additional rows
| Entry | Filed ingredient or declaration |
|---|---|
| Target group | Halal |
| Target group | Gluten Free |
| Target group | Dairy Free |
Source · NIH DSLD 313576 · label 2024-10-24; 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?
NOW has 12 FDA recall records matched by brand name in the enforcement data queried 2026-10-19. NOW 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 |
|---|---|---|---|
| F-1726-2013 | 2013-07-31 | It has been determined that this product contains an undeclared ingredient, licorice extract, which contains glycyrrhizin derived from licorice root. | Terminated |
| F-0770-2014 | 2013-12-25 | Firm is recalling dietary supplements containing a raw material which may contain >0.3 ppb chloramphenicol | Terminated |
| F-1537-2014 | 2014-02-26 | Digestive enzyme capsules manufactured by NOW Foods may contain the antibiotic chloramphenicol. | Terminated |
| F-1484-2017 | 2017-02-22 | Product's supplement fact panel incorrectly states that the product contains 75 mg (milligrams) of Molybdenum, when it actually contains 75 mcg (micrograms). | Terminated |
| F-0682-2019 | 2018-12-12 | NOW Health Group Inc. initiated a voluntary recall of NOW s Vitamin B-50 mg 100 Veg Caps product code 0420 because it is mislabeled as Vitamin B-50 mg 100 Veg Caps. | Terminated |
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 313576 · label 2024-10-24; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
Which labels are closest to this one, with the same salt and dose?
2 labels use the same resolved citrate within ±10% of this label's 400 mg per unit, compared side by side on price and capsule verdict.
computed| Label | Elemental per unit | Price | Verdict |
|---|---|---|---|
| NOW Magnesium Citrate | 400 mg | No price | Needs size 000 |
| NOW Magnesium Citrate Softgels | 400 mg | No price | Capsule sizes do not apply |
Source · NIH DSLD 313576 · label 2024-10-24; 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 313576 (label 2024-10-24, snapshot 2026-08-10) and the chemistry model of 2026-09-13. 1 gap remain: No US retail price matched as of 2026-11-02 (barcode 7 33739 01294 4). The CSV carries the values shown here.
measured| Field | As filed |
|---|---|
| NIH DSLD label | NIH DSLD 313576 |
| Scanned label (PDF) | Label 313576 scan |
| Label date | 2024-10-24 |
| Date entered into DSLD | 2024-10-24 |
| Barcode (UPC) as filed | 7 33739 01294 4 |
| Label version · Package size difference, same product | NIH DSLD 244902 |
| Label version · Package size difference, same product | NIH DSLD 14589 |
| Label version · Package size difference, same product | NIH DSLD 51745 |
39 additional rows
| Field | As filed |
|---|---|
| Label version · Package size difference, same product | NIH DSLD 70609 |
| Label version · Package size difference, same product | NIH DSLD 74147 |
| Label version · Package size difference, same product | NIH DSLD 244901 |
| Label version · Package size difference, same product | NIH DSLD 313577 |
| Label version · Image difference, same product | NIH DSLD 14589 |
| Label version · Image difference, same product | NIH DSLD 51745 |
| Label version · Image difference, same product | NIH DSLD 70609 |
| Label version · Image difference, same product | NIH DSLD 74147 |
| Label version · Image difference, same product | NIH DSLD 244901 |
| Label version · Package size difference, same product | NIH DSLD 204979 |
| Label version · Package size difference, same product | NIH DSLD 335269 |
| Manufactured by | NOW FOODS, Bloomingdale, IL, USA |
| Claim category as filed | Nutrient |
| Claim category as filed | All Other |
| Claim category as filed | Structure/Function |
| Suggested/Recommended/Usage/Directions | Suggested Usage:Take 3 capsules daily, preferably in divided doses, with food. |
| Formula re: Contains | Magnesium is a mineral that is critical for energy production and metabolism, muscle contraction, nerve impulse transmission, and bone mineralization. It is a required cofactor for an estimated 300 enzymes. Among the reactions catalyzed by these enzymes are fatty acid synthesis, protein synthesis, and glucose metabolism. Magnesium status is also important for regulation of calcium balance through its effects on the parathyroid gland. |
| FDA Disclaimer Statement | These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease. |
| Precautions re: Children | Caution: For adults only. |
| Precautions re: Pregnant or Nursing or Prescription Medications | Consult physician if pregnant/nursing, taking medication, or have a medical condition. |
| Precautions re: Children | Keep out of reach of children. |
| Formulation re: Other | Natural color variation may occur in this product. |
| General Statements: All Other Content | This bottle is made from 100% PCR (post-consumer recycled) resin. |
| Formulation re: Other | Nervous system support Supports energy production Critical for enzyme function |
| Formulation re: Does NOT Contain | Non-GMO |
| FDA Statement of Identity | A Dietary Supplement |
| Formulation re: Vegetarian/Vegan | Vegetarian/Vegan |
| Seals/Symbols | Triangle K (Kosher) |
| Formula re: Kosher | Triangle K (Kosher) |
| General Statements: All Other Content | Minerals Family owned since 1968. |
| Formulation re: Other | Made and quality tested in the USA with globally sourced ingredients. |
| Formulation re: Does NOT Contain | Not manufactured with wheat, gluten, soy, milk, egg, fish, shellfish, tree nut or sesame ingredients. |
| Precautions re: Allergies | Not manufactured with wheat, gluten, soy, milk, egg, fish, shellfish, tree nut or sesame ingredients. Produced in a GMP facility that processes other ingredients containing these allergens. |
| Formula re: Contains | This Magnesium Citrate is a fully reacted mineral supplement. |
| Storage | Store in a cool, dry place after opening. |
| Seals/Symbols | Crescent H Halal GMP Quality Assured |
| Formula re: Type | Crescent H Halal |
| Physical state | Capsule |
| Registry snapshot | 2026-08-10 |
Source · NIH DSLD 313576 · label 2024-10-24; 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.