21st Century Magnesium 250 mg

Label facts and derived measurements

The numbers for this label

21st Century Magnesium 250 mg has 11 published fields below, traced to NIH DSLD 258459 and the 2026-08-10 registry snapshot, with calculations dated 2026-09-13.

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

21st Century Magnesium 250 mg retains 1 magnesium-related rows in NIH DSLD 258459, including 1 rows selected for the primary serving, from label 2021-12-18, examined 2026-09-13.

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

21st Century Magnesium 250 mg works out to 110 days per package at the label's own serving and filed frequency of 1 servings per day, according to label 2021-12-18, calculated 2026-09-13.

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.

Percent daily value · observed and computed

The label's percent daily value, recomputed

21st Century Magnesium 250 mg files 1 magnesium percent-daily-value entries in NIH DSLD 258459; the check below applies the group-specific references in 21 CFR 101.9 to its 250 mg primary serving, calculated 2026-09-13.

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

21st Century Magnesium 250 mg lists 5 other ingredients in NIH DSLD 258459, label dated 2021-12-18, examined 2026-09-13.

Capsule material: vegetarian. The material classification follows the filed ingredient names; it is not a test of the shell.

Label declarations · observed

Target groups as filed

21st Century Magnesium 250 mg has 2 target-group entries in NIH DSLD 258459, label dated 2021-12-18, examined 2026-09-13.

Provenance · observed

Registry record, versions and scanned label

The registry holds 2 versions of this label for 21st Century Magnesium 250 mg, according to the retained record examined 2026-09-13; the label date is 2021-12-18.

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

21st Century Magnesium 250 mg has 2 unresolved data gaps in the retained NIH DSLD and price records 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.