Label arithmetic · NIH DSLD 202431
Swanson Magnesium 200 mg
Swanson Magnesium 200 mg declares 400 mg of elemental magnesium as oxide, which needs 332 mg of salt per unit and fits a standard size 0 capsule; NIH DSLD 202431, label dated 2019-11-21, calculation 2026-09-13.
FDA recall records for Swanson: 6 · queried 2026-09-13; brand-string matches across products.
Mass budget · computed; capsule comparison · modelled
What the declared salt would weigh
Swanson Magnesium 200 mg declares 400 mg of elemental magnesium per serving in NIH DSLD 202431, requiring 663.13 mg of magnesium oxide under the salt model calculated 2026-09-13.
| Step | Value | Evidence |
|---|---|---|
| Declared elemental magnesium | 400 mg per serving | observed · label 2019-11-21 |
| Resolved salt | Magnesium oxide · label-row | computed · name resolved from filed text |
| Reference formula | MgO; 40.3 g/mol | computed · chemical reference |
| Elemental fraction | 60.32% by mass | computed |
| Compound mass per serving | 663.13 mg = 400 mg ÷ elemental fraction | computed |
| Compound mass per discrete unit | 331.56 mg | computed |
At powder density 0.6–0.8 g/mL, 332 mg of powder fits a size 0 capsule (holds about 545 mg).
The verdict uses the most favourable reading for the product — the smallest compound mass the label allows. It excludes the shell and other ingredients; their unreported masses are not added as guesses.
Size 0 holds about 545 mg, size 00 about 730 mg, and size 000 about 1,100 mg at powder density 0.6–0.8 g/mL. These are model inputs, not measurements of this product's capsule. Read the mass-budget method.
Label facts and derived measurements
The numbers for this label
Swanson Magnesium 200 mg has 11 published fields below, traced to NIH DSLD 202431 and the 2026-08-10 registry snapshot, with calculations dated 2026-09-13.
| Field | Value | Evidence tier |
|---|---|---|
| NIH DSLD identifier | 202431 | observed |
| Resolved salt | Magnesium oxide | computed |
| Source of the resolved salt | label-row | observed |
| Elemental magnesium per serving (mg) | 400 | observed |
| Servings per container | 125 | observed |
| Elemental magnesium per container (mg) | 50000 | computed |
| Compound mass per discrete unit | 331.56 mg | computed |
| Capsule fill verdict | fits-0 | modelled |
| Required standard capsule size | 0 | modelled |
| Label date | 2019-11-21 | observed |
| Retail match confidence | unmatched | computed |
Observed means a value transcribed from a label or price observation. Computed means arithmetic or normalization of those inputs. Modelled means the result depends on a stated physical assumption, including capsule capacity. Evidence tiers and their limits.
Source transcription · observed
Magnesium lines as filed
Swanson Magnesium 200 mg retains 1 magnesium-related rows in NIH DSLD 202431, including 1 rows selected for the primary serving, from label 2019-11-21, examined 2026-09-13.
| Filed amount | Serving order | Filed salt / notes | Calculation role |
|---|---|---|---|
| 400 mg | 1 | oxide Magnesium (Form: as Magnesium Oxide) | Selected primary serving |
The elemental amount comes from the selected magnesium line. A salt named under another nutrient does not make that nutrient's quantity an elemental magnesium value. Distinct unresolved primary amounts remain ambiguous; they are not added together.
Package arithmetic · observed inputs, computed totals
What the package works out to
Swanson Magnesium 200 mg works out to 125 days per package at the label's own serving and filed frequency of 1 servings per day, according to label 2019-11-21, calculated 2026-09-13.
| Net contents as filed | 250 Capsule(s) |
|---|---|
| Discrete units in the package | 250 |
| Serving size as filed | 2 Capsule(s) |
| Units per serving | 2 |
| Servings per package | 125 |
| Daily servings in the label instructions | 1 |
| Days per package at the label's own serving | 125 days |
Days = filed servings per container ÷ filed servings per day. If the label gives a frequency range, the largest frequency gives the shortest duration. Cost per serving = observed item price ÷ filed servings; cost per label-day multiplies this by the filed frequency. This follows the label's own instructions; it is package arithmetic, not intake advice.
Benchmark · 14 observed prices in oxide
A same-salt reference for this package
At the median cost per 100 mg observed across 14 oxide labels ($0.0571), a package of this size (50,000 mg elemental in Swanson Magnesium 200 mg) would correspond to $28.52, using observations from 2026-08-10 to 2026-09-11, calculated 2026-09-13. This is a benchmark, not a retailer quote.
| Salt and number of observations | Magnesium oxide · n = 14 |
|---|---|
| Median observed cost per 100 mg | $0.0571 |
| Filed elemental magnesium per package | 50,000 mg |
| Benchmark package equivalent | $28.52 = median EC100 × package elemental mg ÷ 100 |
| Evidence tier | benchmark · calculated 2026-09-13 |
The median is the middle sorted observation, or the average of the two middle observations for an even group. Each label contributes one observation. This value is neither an offer nor an estimate of a specific retailer's current price.
Percent daily value · observed and computed
The label's percent daily value, recomputed
Swanson Magnesium 200 mg files 1 magnesium percent-daily-value entries in NIH DSLD 202431; the check below applies the group-specific references in 21 CFR 101.9 to its 400 mg primary serving, calculated 2026-09-13.
| Group as filed | Declared | Reference | Recomputed | Difference |
|---|---|---|---|---|
| Adults and children 4 or more years of age | 95% | 420 mg | 95% | 0 percentage points |
Percent daily value = declared elemental mg ÷ the group's reference mg × 100, rounded to an integer. The adult and age-four-plus reference is 420 mg. Historical labels can use earlier references; a difference does not establish a filing error. Full-record entries may cover multiple serving sizes, so this table identifies the primary-serving basis explicitly. Group references and interpretation.
Composition · observed
Other ingredients in the filed record
Swanson Magnesium 200 mg lists 3 other ingredients in NIH DSLD 202431, label dated 2019-11-21, examined 2026-09-13.
| Entry | Ingredient |
|---|---|
| 1 | Rice Flour |
| 2 | Gelatin |
| 3 | Magnesium Stearate |
Capsule material: gelatin. The material classification follows the filed ingredient names; it is not a test of the shell.
This label lists magnesium stearate, whose reference elemental fraction is 4.1% by mass. No stearate quantity is available in this record as of 2026-09-13, so its magnesium contribution cannot be quantified or added to the Supplement Facts magnesium total.
Label declarations · observed
Target groups as filed
Swanson Magnesium 200 mg has 1 target-group entries in NIH DSLD 202431, label dated 2019-11-21, examined 2026-09-13.
| Entry | Filed group |
|---|---|
| 1 | Adult (18 - 50 Years) |
Provenance · observed
Registry record, versions and scanned label
The registry holds 5 versions of this label for Swanson Magnesium 200 mg, according to the retained record examined 2026-09-13; the label date is 2019-11-21.
| NIH DSLD label | NIH DSLD 202431 |
|---|---|
| Registry snapshot | 2026-08-10 |
| Label date | 2019-11-21 |
| Physical state | Capsule |
| Barcode as filed | 0 87614 01196 7 |
| Versions held by the registry | 5; version details are not available in this enrichment record as of 2026-09-13 |
| Calculation date | 2026-09-13 |
The barcode is retained as an identifier, not as proof of a retail match. A registry version count records the number held; it does not reveal what changed. The label date, registry snapshot and price-observation date describe different events.
Gaps in this record
What is not available for this label
Swanson Magnesium 200 mg has 1 unresolved data gaps in the retained NIH DSLD and price records as of 2026-09-13.
| Entry | Known gap |
|---|---|
| 1 | No confirmed US retail price matched to NIH DSLD 202431 (barcode 0 87614 01196 7) as of 2026-09-13. |
An unmatched retail price describes our matching coverage. It does not establish that a product is unavailable. The elemental cost calculator can apply the same EC100 formula to a price you supply.