Label arithmetic · NIH DSLD 72119
NOW Magnesium Oxide Pure Powder: 290 mg of magnesium per 1/4 teaspoon, 454 servings
290 mg of magnesium in each 1/4 tsp, about 454 servings per 8 oz. Oxide is 60.3% magnesium; no US price matched (Nov 2). Inside: salt per scoop, %DV check.
NOW Magnesium Oxide Pure Powder declares 290 mg of elemental magnesium per serving as oxide, which means 481 mg of magnesium oxide powder in one serving, compared with 1,100 mg in the largest standard capsule; that is the weight of the salt alone, before any fillers or flavours in the scoop. No US retail price matched as of 2026-11-02; 10 of the 61 oxide labels in this registry have a matched price. NIH DSLD 72119, label dated 2017-04-25.
computed from the filed label
Chart data
| Displayed chart text |
|---|
| gluconate |
| 4,949 |
| orotate |
| 3,989 |
| L-threonate |
| 3,515 |
| taurate |
| 3,251 |
| lactate |
| 2,415 |
| glycerophosphate |
| 2,320 |
| glycinate |
| 2,057 |
| malate |
| 1,866 |
| aspartate |
| 1,854 |
| citrate |
| 1,795 |
| sulfate |
| 1,436 |
| chloride |
| 1,136 |
| carbonate |
| 1,006 |
| hydroxide |
| 696 |
| oxide |
| 481 |
Data release 2026-08-10-f441aa9f · registry snapshot 2026-08-10 · latest price observation 2026-10-19 · chemistry 2026-10-17
Mass: 481 mg per serving · Price: none matched · % DV: 69% vs 69%
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.
How much oxide powder is in one scoop?
NOW Magnesium Oxide Pure Powder carries 481 mg of magnesium oxide per serving for 290 mg of elemental magnesium, against 1,100 mg in the largest standard capsule; capsule capacities do not apply to this powder.
computed with assumption| Measure | Value |
|---|---|
| Elemental magnesium per serving | 290 mg |
| Units per serving | Not a discrete unit as of 2026-11-02 |
| Magnesium oxide per serving | 481 mg |
| Magnesium oxide per serving | Not computable as of 2026-11-02 |
| Capsule capacity 0 · 00 · 000 | 545 · 730 · 1,100 mg |
| Verdict | Capsule sizes do not apply |
Source · NIH DSLD 72119 · label 2017-04-25; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
How much elemental magnesium is actually in this label's filed magnesium lines?
NOW Magnesium Oxide Pure Powder files 1 magnesium line in NIH DSLD 72119; the selected primary line declares 290 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 |
|---|---|---|
| 290 mg | oxide · Magnesium (Form: from Magnesium Oxide) | Primary serving |
Source · NIH DSLD 72119 · label 2017-04-25; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
Does this label's oxide claim hold up, or could the magnesium come from another source?
The label names one magnesium form, oxide, resolved from the filed magnesium line; capsule capacities do not apply to this form, compared with oxide, the salt richest in magnesium at 60.3%.
computed with assumption| Form named on the label | Elemental fraction | Source |
|---|---|---|
| Magnesium oxide | 60.3% | filed magnesium line |
Source · NIH DSLD 72119 · label 2017-04-25; 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; 10 of 61 oxide labels have one, against a median of $0.0293 per 100 mg among 5 ranked oxide offers.
computed
Chart data
| Displayed chart text |
|---|
| n=5 |
| P25 $0.0258 |
| P75 $0.0356 |
| median $0.0293 |
| Rank | Label | Per 100 mg | Observed |
|---|---|---|---|
| 1 | Nutricost Magnesium Oxide | $0.0148 | 2026-11-02 |
| 2 | tnvitamins Magnesium Oxide 420 mg | $0.0258 | 2026-11-02 |
| 3 | Douglas Laboratories Magnesium Oxide | $0.0293 | 2026-11-02 |
| 4 | Wonder Labs Magnesium Oxide 400 | $0.0356 | 2026-11-02 |
| 5 | Carlson Magnesium Gels 400 mg | $0.0636 | 2026-11-02 |
| Median | 5 ranked oxide offers | $0.0293 | 2026-11-02 |
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, NOW Magnesium Oxide Pure Powder lasts 454 days: 454 servings against 1 serving a day in the filed directions.
computed| Measure | Value |
|---|---|
| Net contents as filed | 8 oz.; 227 Gram(s) |
| Serving size as filed | 0.25 tsp (approx. 500 mg) |
| Servings per container | 454 |
| Servings per day in the directions | 1 |
| Days per bottle | 454 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 72119 · label 2017-04-25; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
What does "69% Daily Value" mean here, and does it recompute?
The label declares 69% Daily Value; 290 mg against the 420 mg reference in 21 CFR 101.9 recomputes to 69%, the same within one point.
computed| Group as filed | Declared | Reference | Recomputed |
|---|---|---|---|
| Adults and children 4 or more years of age | 69% | 420 mg | 69% |
Source · NIH DSLD 72119; 21 CFR 101.9 · label 2017-04-25 · 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?
NOW Magnesium Oxide Pure Powder files 1 other ingredient, and no magnesium stearate, against 30 of 61 oxide labels that list magnesium stearate.
measured| Entry | Filed ingredient or declaration |
|---|---|
| 1 | None |
| Target group | Vegan |
| Target group | Vegetarian |
| Target group | Adult (18 - 50 Years) |
| Target group | Gluten Free |
| Target group | Dairy Free |
Source · NIH DSLD 72119 · label 2017-04-25; snapshot 2026-08-10 · release 2026-08-10-f441aa9f · CSV · method
What has research measured about oxide, and about side effects?
12 studies in the PubMed-checked registry measured outcomes involving oxide; 2 mention gastrointestinal or adverse outcomes. They measured the salt, not this label.
measured| Year | Study | PubMed |
|---|---|---|
| 2026 | Randomized, open-label study of the short-term pharmacokinetics of oral magnesium oxide in healthy volunteers. | 42091979 |
| 2024 | Comparative Clinical Study on Magnesium Absorption and Side Effects After Oral Intake of Microencapsulated Magnesium (MAGSHAPE™ Microcapsules) Versus Other Magnesium Sources. | 39770988 |
| 2022 | Effects of short-term magnesium supplementation on ionized, total magnesium and other relevant electrolytes levels. | 35041150 |
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?
NOW has 12 FDA recall records matched by brand name in the enforcement data queried 2026-10-19. NOW 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-1726-2013 | 2013-07-31 | It has been determined that this product contains an undeclared ingredient, licorice extract, which contains glycyrrhizin derived from licorice root. | Terminated |
| F-0770-2014 | 2013-12-25 | Firm is recalling dietary supplements containing a raw material which may contain >0.3 ppb chloramphenicol | Terminated |
| F-1537-2014 | 2014-02-26 | Digestive enzyme capsules manufactured by NOW Foods may contain the antibiotic chloramphenicol. | Terminated |
| F-1484-2017 | 2017-02-22 | Product's supplement fact panel incorrectly states that the product contains 75 mg (milligrams) of Molybdenum, when it actually contains 75 mcg (micrograms). | Terminated |
| F-0682-2019 | 2018-12-12 | NOW Health Group Inc. initiated a voluntary recall of NOW s Vitamin B-50 mg 100 Veg Caps product code 0420 because it is mislabeled as Vitamin B-50 mg 100 Veg Caps. | 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 72119 · label 2017-04-25; 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 72119 · label 2017-04-25; 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 72119 (label 2017-04-25, snapshot 2026-08-10) and the chemistry model of 2026-09-13. 1 gap remain: No US retail price matched as of 2026-11-02 (barcode 7 33739 01310 1). The CSV carries the values shown here.
measured| Field | As filed |
|---|---|
| NIH DSLD label | NIH DSLD 72119 |
| Label date | 2017-04-25 |
| Date entered into DSLD | 2017-04-25 |
| Barcode (UPC) as filed | 7 33739 01310 1 |
| Label version · Image difference, same product | NIH DSLD 14596 |
| Label version · Image difference, same product | NIH DSLD 40289 |
| Label version · Image difference, same product | NIH DSLD 51758 |
| Label version · Image difference, same product | NIH DSLD 60659 |
27 additional rows
| Field | As filed |
|---|---|
| Manufacturer | NOW Foods, Bloomingdale, IL, USA |
| Claim category as filed | All Other |
| Claim category as filed | Structure/Function |
| Suggested/Recommended/Usage/Directions | Suggested Usage: Mix 1/4 level teaspoon of powder into at least 6 oz. of cold water or clear liquid. Take once daily with a meal. Pure Magnesium Oxide Powder can increase the temperature of liquids upon contact; therefore, the recommended serving must be mixed into at least 6 oz. of cold liquid to neutralize this reaction prior to ingestion. |
| General Statements: All Other Content | Magnesium is a mineral that is critical for energy production and metabolism, muscle contraction, nerve impulse transmission, and bone mineralization.* It is a required cofactor for an estimated 300 enzymes.* Among the reactions catalyzed by these enzymes are fatty acid synthesis, protein synthesis, and glucose metabolism.* Magnesium status is also important for regulation of calcium balance through its effects on the parathyroid gland.* |
| 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. |
| Formulation re: Does NOT Contain | Non-GMO |
| Precautions re: All Other | Caution: This product must be dissolved into at least 6 oz. of cold water or clear liquid before consuming. Do not breathe powder and avoid contact with skin, eyes, and clothing. For adults only. |
| Precautions re: Pregnant or Nursing or Prescription Medications | Consult physician if pregnant/nursing, taking medication, or have a medical condition. |
| Precautions re: Children | Keep out of reach of children. |
| General Statements: All Other Content | Natural color variation may occur in this product. |
| General: Product/Version Code | CODE 1310 V5 |
| General Statements: All Other Content | Nervous system support* |
| General Statements: All Other Content | ~ Supports energy production* ~ Critical for enzyme function* |
| Seals/Symbols | NON GMO Project Verified nongmoproject.org |
| FDA Statement of Identity | A Dietary Supplement |
| Formulation re: Vegetarian/Vegan | Vegetarian/Vegan |
| General Statements: All Other Content | Minerals |
| General Statements: All Other Content | Family owned since 1968. |
| Formulation re: Does NOT Contain | Not manufactured with wheat, gluten, soy, milk, egg, fish, shellfish or tree nut ingredients. |
| Precautions re: Allergies | Not manufactured with wheat, gluten, soy, milk, egg, fish, shellfish or tree nut ingredients. Produced in a GMP facility that processes other ingredients containing these allergens. |
| Storage | Store in a cool, dry place after opening. |
| General Statements: All Other Content | Please recycle. |
| Seals/Symbols | GMP Quality Assured |
| General Statements: All Other Content | This product is sold by weight not volume. |
| Physical state | Powder |
| Registry snapshot | 2026-08-10 |
Source · NIH DSLD 72119 · label 2017-04-25; 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.