Label arithmetic · NIH DSLD 318035
Xtendlife Marine Magnesium with Potassium: 265 mg of magnesium per capsule, 2 capsules a day (salt not resolved)
265 mg of magnesium per capsule; the label's 2 capsules a day give 530 mg. Salt not resolved from the NIH record. Inside: label lines, ingredients.
Xtendlife Marine Magnesium with Potassium declares 530 mg of elemental magnesium per 2 capsule(s); the magnesium salt is not resolved from the filed record, Single-salt capacity audit excluded as of 2026-10-17: one salt with a defined elemental fraction is not resolved., as of 2026-11-02. No US retail price matched as of 2026-11-02. NIH DSLD 318035, label dated 2024-10-24.
as filedData release 2026-08-10-f441aa9f · registry snapshot 2026-08-10 · latest price observation 2026-10-19 · chemistry 2026-10-17
Mass: not computable · Price: none matched · % DV: 126% vs 126%
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 530 mg of magnesium actually fit in one capsule, or do I need more than one?
The compound mass behind this label cannot be computed as of 2026-11-02: Single-salt capacity audit excluded as of 2026-10-17: one salt with a defined elemental fraction is not resolved.. The filed amounts are listed in the next block. Lower bound, not a measurement: even if all 530 mg of magnesium per serving came from magnesium hydroxide (41.7% magnesium), the form named for magnesium on the label, each of the 2 capsules would need at least 636 mg of compound, so at this bound it needs at least a size 00 capsule (about 730 mg at 0.8 g/mL); the actual mix of forms may need more.
computed with assumption| Measure | Value |
|---|---|
| Elemental magnesium per serving | 530 mg |
| Units per serving | 2 |
| Magnesium salt per serving | Not computable as of 2026-11-02 |
| Magnesium salt per capsule | Not computable as of 2026-11-02 |
| Capsule capacity 0 · 00 · 000 | 545 · 730 · 1,100 mg |
| Verdict | Not computable as of 2026-11-02 |
Source · NIH DSLD 318035 · 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?
Xtendlife Marine Magnesium with Potassium files 1 magnesium line in NIH DSLD 318035; the selected primary line declares 530 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 |
|---|---|---|
| 530 mg | Salt not named in this row as of 2026-11-02 | Primary serving |
Source · NIH DSLD 318035 · label 2024-10-24; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
Does this label's magnesium claim hold up, or could the magnesium come from another source?
No single magnesium salt is resolved from the filed record as of 2026-11-02, so the source of the declared magnesium cannot be checked against capsule capacity, compared with oxide, the salt richest in magnesium at 60.3%.
computed with assumption| Form named on the label | Elemental fraction | Source |
|---|---|---|
| No form named as of 2026-11-02 | No defined fraction | named on label |
Source · NIH DSLD 318035 · 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, and without a resolved salt there is no same-salt comparison.
computed| Rank | Label | Per 100 mg | Observed |
|---|
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, Xtendlife Marine Magnesium with Potassium lasts 30 days: 30 servings against 1 serving a day in the filed directions.
computed| Measure | Value |
|---|---|
| Net contents as filed | 60 Vegetarian Capsule(s) |
| Serving size as filed | 2 Capsule(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 318035 · label 2024-10-24; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
What does "126% Daily Value" mean here, and does it recompute?
The label declares 126% Daily Value; 530 mg against the 420 mg reference in 21 CFR 101.9 recomputes to 126%, the same within one point.
computed| Group as filed | Declared | Reference | Recomputed |
|---|---|---|---|
| Adults and children 4 or more years of age | 126% | 420 mg | 126% |
Source · NIH DSLD 318035; 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?
Xtendlife Marine Magnesium with Potassium files 3 other ingredients and a vegetarian shell.
measured| Entry | Filed ingredient or declaration |
|---|---|
| 1 | Hydroxypropyl Methylcellulose |
| 2 | Water |
| 3 | Gum Arabic |
| Shell | vegetarian |
| Target group | Adult (18 - 50 Years) |
Source · NIH DSLD 318035 · label 2024-10-24; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
What has research measured about this form, and about side effects?
No study in the registry measured an unresolved salt as of 2026-11-02.
measured| Year | Study | PubMed |
|---|
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?
Xtendlife has 0 FDA recall records matched by brand name in the enforcement data queried 2026-10-19. Xtendlife has no FDA CAERS adverse event report on record at brand level as of 2026-10-19 (143 of 273 brands in this registry have at least one CAERS report).
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 318035 · 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?
No other label files the same resolved salt within ±10% of this label's dose per unit as of 2026-11-02.
computed| Label | Elemental per unit | Price | Verdict |
|---|---|---|---|
| No neighbour as of 2026-11-02 |
Source · NIH DSLD 318035 · 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 318035 (label 2024-10-24, snapshot 2026-08-10) and the chemistry model of 2026-09-13. 3 gaps remain: Single-salt capacity audit excluded as of 2026-10-17: one salt with a defined elemental fraction is not resolved.; No US retail price matched as of 2026-11-02 (barcode 9 421904 523180); A single salt with a defined elemental fraction is unresolved as of 2026-11-02. The CSV carries the values shown here.
measured| Field | As filed |
|---|---|
| NIH DSLD label | NIH DSLD 318035 |
| Scanned label (PDF) | Label 318035 scan |
| Label date | 2024-10-24 |
| Date entered into DSLD | 2024-10-24 |
| Barcode (UPC) as filed | 9 421904 523180 |
| Label version · Image difference, same product | NIH DSLD 283402 |
| Made in New Zealand using imported ingredients by | Natural Products (NZ) LTD Member of the Xtend-Life Group, Christchurch, New Zealand |
| Claim category as filed | Nutrient |
14 additional rows
| Field | As filed |
|---|---|
| Claim category as filed | All Other |
| Claim category as filed | Structure/Function |
| Suggested/Recommended/Usage/Directions | Directions For Use Adults: 2 capsules per day. For optimum results take after evening meal. |
| Formula re: Contains | Xtend-Life Marine Magnesium and Potassium contains AQUAMIN magnesium, which is derived from seawater. It includes 72 trace minerals, and it is an excellent source of natural bioavailable magnesium hydroxide to support cardiovascular and general health. |
| 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. |
| FDA Statement of Identity | Dietary Supplement |
| Formula re: Contains | Natural magnesium formula |
| Formulation re: Other | Quality Ingredients |
| Seals/Symbols | Best quality guarantee |
| Seals/Symbols | NewZealand.com Licence No.100055 |
| General Statements: All Other Content | USA/Canada Ph: 1 888 487 9304 |
| Physical state | Capsule |
| Registry snapshot | 2026-08-10 |
Source · NIH DSLD 318035 · 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.