Label arithmetic · NIH DSLD 328641
Life Extension Potassium with Extend-Release Magnesium: 250 mg of magnesium per capsule, 1–2 capsules a day (salt not resolved)
250 mg of magnesium per capsule; the label's 1–2 capsules a day give 250–500 mg. Salt not resolved from the NIH record. Inside: label lines, ingredients.
Life Extension Potassium with Extend-Release Magnesium declares 250 mg of elemental magnesium per 1 vegetarian 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 328641, label dated 2025-05-21.
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: 60% vs 60%
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 250 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 250 mg of magnesium per serving came from magnesium oxide (60.3% magnesium), the richest magnesium salt used in supplements, because the label names no form, the single capsule would need at least 414 mg of compound, so at this bound it needs at least a size 0 capsule (about 545 mg at 0.8 g/mL); the actual form, which the label does not name, may need more.
computed with assumption| Measure | Value |
|---|---|
| Elemental magnesium per serving | 250 mg |
| Units per serving | 1 |
| 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 328641 · label 2025-05-21; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
How much elemental magnesium is actually in this label's filed magnesium lines?
Life Extension Potassium with Extend-Release Magnesium files 1 magnesium line in NIH DSLD 328641; the selected primary line declares 250 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 |
|---|---|---|
| 250 mg | Salt not named in this row as of 2026-11-02 | Primary serving |
Source · NIH DSLD 328641 · label 2025-05-21; 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 328641 · label 2025-05-21; 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, Life Extension Potassium with Extend-Release Magnesium lasts 30–60 days: 60 servings against 1–2 servings a day in the filed directions.
computed| Measure | Value |
|---|---|
| Net contents as filed | 60 Vegetarian Capsule(s) |
| Serving size as filed | 1 Vegetarian Capsule(s) |
| Servings per container | 60 |
| Servings per day in the directions | 1–2 |
| Days per bottle | 30–60 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 328641 · label 2025-05-21; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
What does "60% Daily Value" mean here, and does it recompute?
The label declares 60% Daily Value; 250 mg against the 420 mg reference in 21 CFR 101.9 recomputes to 60%, the same within one point.
computed| Group as filed | Declared | Reference | Recomputed |
|---|---|---|---|
| Adults and children 4 or more years of age | 60% | 420 mg | 60% |
Source · NIH DSLD 328641; 21 CFR 101.9 · label 2025-05-21 · 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?
Life Extension Potassium with Extend-Release Magnesium files 8 other ingredients and a vegetarian shell.
measured| Entry | Filed ingredient or declaration |
|---|---|
| 1 | Cellulose |
| 2 | Microcrystalline Cellulose |
| 3 | Rice Concentrate |
| 4 | Ethylcellulose |
| 5 | Medium Chain Triglyceride |
| 6 | Oleic Acid |
| 7 | Hydroxypropyl Methylcellulose |
| 8 | Silica |
3 additional rows
| Entry | Filed ingredient or declaration |
|---|---|
| Shell | vegetarian |
| Target group | Adult (18 - 50 Years) |
| Target group | Gluten Free |
Source · NIH DSLD 328641 · label 2025-05-21; 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?
Life Extension has 0 FDA recall records matched by brand name in the enforcement data queried 2026-10-19. Life Extension 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 |
|---|---|---|---|
| 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 328641 · label 2025-05-21; 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 328641 · label 2025-05-21; 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 328641 (label 2025-05-21, 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 7 37870 23096 0); 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 328641 |
| Scanned label (PDF) | Label 328641 scan |
| Label date | 2025-05-21 |
| Date entered into DSLD | 2025-05-21 |
| Barcode (UPC) as filed | 7 37870 23096 0 |
| Label version · Image difference, same product | NIH DSLD 232470 |
| Label version · Image difference, same product | NIH DSLD 211017 |
| Manufactured for | Quality Supplements and Vitamins, Inc., Ft. Lauderdale, FL |
18 additional rows
| Field | As filed |
|---|---|
| Claim category as filed | Nutrient |
| Claim category as filed | All Other |
| General Statements: All Other Content | Scan for product info |
| Precautions re: All Other | Read the entire label and follow directions carefully prior to use. |
| Suggested/Recommended/Usage/Directions | Directions: Take one (1) capsule once or twice daily, or as recommended by a healthcare practitioner. |
| Precautions re: All Other | Caution: If taken in high doses, magnesium may have a laxative effect. If this occurs, divide dosing, reduce intake, or discontinue product. |
| Precautions re: Children | Warnings: Keep out of reach of children. |
| Precautions re: All Other | Do not exceed recommended dose. Do not purchase if outer seal is broken or damaged. |
| Precautions re: Pregnant or Nursing or Prescription Medications | When using nutritional supplements, please consult with your physician if you are undergoing treatment for a medical condition or if you are pregnant or lactating. |
| Brand IP Statement(s) re: (c), (TM), (SM) | ZumXR is a registered trademark and protected by patents. See www.ZumXR.com. |
| Formulation re: Does NOT Contain | Gluten free Non GMO LE Certified |
| Seals/Symbols | Non GMO LE Certified |
| Formula re: Contains | IR Potassium with 6 hour XR Magnesium |
| FDA Statement of Identity | Dietary Supplement |
| Precautions re: All Other | To report a serious adverse event or obtain product information, contact 1-866-280-2852. |
| Storage | Store tightly closed in a cool, dry place. |
| Physical state | Capsule |
| Registry snapshot | 2026-08-10 |
Source · NIH DSLD 328641 · label 2025-05-21; 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.