Label arithmetic · NIH DSLD 308656
Swanson Magnesium Aspartate: 133 mg of magnesium per capsule, 3 capsules a day
133 mg of magnesium per capsule; the label's 3 capsules a day give 399 mg. No US price matched (Nov 2). Inside: salt weight, capsule size.
Swanson Magnesium Aspartate declares 133 mg of elemental magnesium per serving as aspartate, which needs 850–1,776 mg of magnesium aspartate 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. Price observed 2026-09-11; pack or dose match under review, so no cost per 100 mg is shown. NIH DSLD 308656, label dated 2024-03-22.
computed from the filed label
Chart data
| Displayed chart text |
|---|
| 545 mg |
| 730 mg |
| 1,100 mg |
| 850–1,776 mg of aspartate per capsule |
Data release 2026-08-10-f441aa9f · registry snapshot 2026-08-10 · this offer's price observed 2026-09-11 · latest price observation 2026-11-02 · chemistry 2026-10-17
Mass: 850–1,776 mg per capsule · Price: on review · % DV: 32% vs 32%
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 133 mg of aspartate actually fit in one capsule, or do I need more than one?
Estimated salt mass versus assumed capsule capacity: Swanson Magnesium Aspartate implies 850–1,776 mg of magnesium aspartate in each capsule to deliver 133 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.
computed with assumption| Measure | Value |
|---|---|
| Elemental magnesium per serving | 133 mg |
| Units per serving | 1 |
| Magnesium aspartate per serving | 850–1,776 mg |
| Magnesium aspartate per capsule | 850–1,776 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 (1:1 magnesium aspartate 15.64%; bis(hydrogen aspartate) 8.42%, its dihydrate 7.49%; stoichiometry and hydration unresolved), so the compound mass is a range.
Source · NIH DSLD 308656 · label 2024-03-22; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
Does the label's own text add up on magnesium?
The label's own text says “133 mg elemental magnesium per capsule Magnesium aspartate 685 mg”: 133 mg of magnesium from 685 mg of magnesium aspartate is 19.4% magnesium, against at most 15.6% that magnesium aspartate can carry. By the label's own numbers, at least 19% of the declared magnesium must come from a source other than the aspartate; this is computed from the label's words.
computed| Measure | Value |
|---|---|
| Label text (NIH DSLD statements) | 133 mg elemental magnesium per capsule Magnesium aspartate 685 mg |
| Implied magnesium share | 19.4% |
| Most magnesium aspartate can carry | 15.6% |
| Share needing another source, at least | 19% |
Source · NIH DSLD 308656 label text · snapshot 2026-08-10; salt fractions from the chemistry model · release 2026-08-10-f441aa9f · CSV · method
How much elemental magnesium is actually in this label's filed magnesium lines?
Swanson Magnesium Aspartate files 1 magnesium line in NIH DSLD 308656; the selected primary line declares 133 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 |
|---|---|---|
| 133 mg | Salt not named in this row; magnesium aspartate is taken from the label text | Primary serving |
Source · NIH DSLD 308656 · label 2024-03-22; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
Does this label's aspartate claim hold up, or could the magnesium come from another source?
The label names one magnesium form, aspartate, 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 aspartate | 7.5–15.6% | full NIH DSLD record text |
Source · NIH DSLD 308656 · label 2024-03-22; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
Is this a good price for the elemental magnesium I'm actually getting?
Swanson Magnesium Aspartate was observed at $14.84 on 2026-09-11, but no cost per 100 mg is computed because the offer is a multi-pack (2 packs); against 0 ranked aspartate offers with a median of none.
computed| Rank | Label | Per 100 mg | Observed |
|---|---|---|---|
| On review | Swanson Magnesium Aspartate (this label) | Not computed | 2026-09-11 |
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, Swanson Magnesium Aspartate lasts 30 days: 90 servings against 3 servings a day in the filed directions.
computed| Measure | Value |
|---|---|
| Net contents as filed | 90 Capsule(s) |
| Serving size as filed | 1 Capsule(s) |
| Servings per container | 90 |
| Servings per day in the directions | 3 |
| 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 308656 · label 2024-03-22; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
What does "32% Daily Value" mean here, and does it recompute?
The label declares 32% Daily Value; 133 mg against the 420 mg reference in 21 CFR 101.9 recomputes to 32%, the same within one point.
computed| Group as filed | Declared | Reference | Recomputed |
|---|---|---|---|
| Adults and children 4 or more years of age | 32% | 420 mg | 32% |
Source · NIH DSLD 308656; 21 CFR 101.9 · label 2024-03-22 · release 2026-08-10-f441aa9f · CSV · method
Why does this label contain magnesium stearate, what shell is it, and who is it filed for?
Swanson Magnesium Aspartate files 3 other ingredients, including magnesium stearate (reference fraction 4.1% magnesium; no quantity filed, so it is not added to the total) and a gelatin shell, against 15 of 25 aspartate labels that list magnesium stearate.
measured| Entry | Filed ingredient or declaration |
|---|---|
| 1 | Gelatin |
| 2 | Brown Rice Flour |
| 3 | Magnesium Stearate |
| Shell | gelatin |
| Target group | Adult (18 - 50 Years) |
Source · NIH DSLD 308656 · label 2024-03-22; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
What has research measured about aspartate, and about side effects?
2 studies in the PubMed-checked registry measured outcomes involving aspartate; none reports a gastrointestinal outcome as of 2026-11-02. They measured the salt, not this label.
measured| Year | Study | PubMed |
|---|---|---|
| 2005 | Study of magnesium bioavailability from ten organic and inorganic Mg salts in Mg-depleted rats using a stable isotope approach | 16548135 |
| 2001 | Bioavailability of US commercial magnesium preparations | 11794633 |
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?
Swanson has 6 FDA recall records matched by brand name in the enforcement data queried 2026-10-19. Swanson 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-0705-2013 | 2012-11-28 | This is to inform you of a product recall involving 2 lots of Swanson Organic 100% Certified Organic Fennel Seed (SWF092). Some jars of fennel seeds have been found to contain small, red beetle-type insects. | Terminated |
| F-0220-2014 | 2013-11-27 | Swanson Health Products is recalling two lots of Swanson Premium Full Spectrum Black Cumin Seed (Nigella sativa) Dietary Supplement Capsules. The product was found to be mislabel. Bottles of Black Cumin Seed from these two lots numbers (199399 & 201359) have been found to contain White Cumin Seed (Cuminum cyminum). | Terminated |
| F-1936-2014 | 2014-05-21 | The contract manufacturer has notified Swanson Health Products that Swanson Full Spectrum Cilantro (Coriander) (SW1112) is subject to a recall due to a potential risk of salmonella contamination. | Terminated |
| F-2438-2014 | 2014-09-24 | Swanson Certified Organic Carob Powder, item number SWF115 is being recalled due to a potential risk of Salmonella contamination from a raw ingredient used in this product. | Terminated |
| F-1985-2018 | 2018-10-03 | Himalayan Crystal Salt may contain metal wire pieces. | 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 308656 · label 2024-03-22; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
Which labels are closest to this one, with the same salt and dose?
1 label use the same resolved aspartate within ±10% of this label's 133 mg per unit, compared side by side on price and capsule verdict.
computed| Label | Elemental per unit | Price | Verdict |
|---|---|---|---|
| NOW Magnesium & Potassium Aspartate | 125 mg | $29.62 · 2026-10-26 | Needs size 000 |
Source · NIH DSLD 308656 · label 2024-03-22; 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 308656 (label 2024-03-22, snapshot 2026-08-10), a price observed 2026-09-11 and the chemistry model of 2026-09-13. No data gap remains for the computed fields. The CSV carries the values shown here.
measured| Field | As filed |
|---|---|
| NIH DSLD label | NIH DSLD 308656 |
| Scanned label (PDF) | Label 308656 scan |
| Label date | 2024-03-22 |
| Date entered into DSLD | 2024-03-22 |
| Barcode (UPC) as filed | 0 87614 11420 0 |
| Label version · Image difference, same product | NIH DSLD 181232 |
| Distributed by | Swanson Health Products, Fargo, ND, USA |
| Claim category as filed | Nutrient |
15 additional rows
| Field | As filed |
|---|---|
| Claim category as filed | All Other |
| Claim category as filed | Structure/Function |
| Formulation re: Other | Essential nutrition for cellular energy production Supports hundreds of enzymatic processes in the body |
| Brand IP Statement(s) re: (c), (TM), (SM) | Swanson Science-backed quality since 1969 |
| Suggested/Recommended/Usage/Directions | Suggested use: As a dietary supplement, take one capsule with water three times per day. |
| Precautions re: Children | Warning: For adults only. Keep out of reach of children. |
| Precautions re: Pregnant or Nursing or Prescription Medications | Consult your physician before using this or any product if you are pregnant or nursing, taking medication or have a medical condition. |
| Precautions re: All Other | Do not use if seal is broken. |
| Storage | Store in a cool, dry place. |
| 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. |
| Formula re: Contains | 133 mg elemental magnesium per capsule Magnesium aspartate 685 mg per capsule |
| Formulation re: Other | Energy support |
| FDA Statement of Identity | Mineral Supplement |
| Physical state | Capsule |
| Registry snapshot | 2026-08-10 |
Source · NIH DSLD 308656 · label 2024-03-22; 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.