MgO-400
by 21st Century · tablet or pill · 90 tablets
- On the market (NIH)
- UPC 7 40985 27072 1
- DSLD label 258475
- Serving 2 tablets
MgO-400 by 21st Century lists 2 ingredients, 2 with an amount per serving of 2 tablets, such as 130 mg of calcium and 483 mg of elemental magnesium. Its current label entered the NIH Dietary Supplement Label Database on January 22, 2022.
What is in MgO-400?
Each row as the label prints it, per serving of 2 tablets. The capsule beside an amount places it among every product in the NIH database that lists the same ingredient: the bar is the middle half of their amounts, the line in it the median, the whiskers the 10th and 90th percentiles; the green tick is the FDA Daily Value and the red dashed tick the adult upper limit (IOM).
| Ingredient | Amount | % DV | Among products listing it |
|---|---|---|---|
| Calciumas Calcium CarbonateCalcium (Form: as Calcium Carbonate) | 130 mg | 10% | Higher than 54% of 17,831 products listing calcium (median 115 mg). |
| elemental Magnesiumas Magnesium OxideMagnesium Oxide Note: USP | 483 mg | 115% | Higher than 96% of 14,003 products listing magnesium (median 86 mg). 1.4 times the adult UL a day. |
Source: NIH ODS Dietary Supplement Label Database, label 258475 (entered January 22, 2022), version 9.4.0. See the label on DSLD. Amounts are what the maker printed; DSLD does not test products. Daily Values: the FDA's Daily Value page.
Is that a lot?
The rows in the top or bottom tenth of the products that list the same ingredient, and any above the adult upper limit at the most servings a day the directions give:
- At 1 serving a day, the most its directions give, the label lists 483 mg of magnesium, 1.4 times the adult Tolerable Upper Intake Level.
The NIH database records one serving a day from the label's directions; its % Daily Values are for adults and children 4 or more years of age. The directions as printed are further down this page.
The Tolerable Upper Intake Level is the most of a nutrient per day, from food, water and supplements together, that is likely to pose no risk for almost all adults (Institute of Medicine, 2011). It does not apply under medical supervision. This page compares labels; it is not medical advice.
Sources: amounts from the DSLD label; Daily Values from 21 CFR 101.9(c)(8)(iv); adult upper limits from the Institute of Medicine's DRI summary tables (2011). How positions are computed.
Which products have the closest formulas?
6 products list the very same ingredients; the nearest amounts come first.
- Albion Chelated Magnesium 700 mgVitamin World same ingredients
- Magnesium Plus Calcium 2:1 RatioBluebonnet · off the market same ingredients
- Magnesium & Calcium 2:1 RatioBluebonnet same ingredients
- Magnesium (Magnesium Oxide & Carbonate) 400 mgWindmill Natural Vitamins · off the market same ingredients
- Magnesium 400 mgWindmill Natural Vitamins same ingredients
- Magnesium Calcium ComplexBioCare same ingredients
Source: ingredient lists of every product's current label in DSLD (version 9.4.0); similarity weights each shared ingredient by how rare it is.
What does the label say about taking it?
Quoted from the label as DSLD transcribed it: the maker's words, including any claim about what the product does, which the FDA has not evaluated and PlainVitamins does not endorse.
- Directions
- Directions: As a mineral supplement, adults take two (2) tablets daily with any meal or as directed by a healthcare provider. Do not exceed recommended dosage.
- Warnings
- Do not exceed recommended dosage.
- Warning: Consult a healthcare provider prior to use if pregnant, nursing, on medications, have a medical condition or are planning a medical procedure.
- Stop use and contact a physician if adverse reactions occur.
- Keep out of reach of children.
- Do not use if product appears to be tampered with or seal is broken.
- Allergens and what it does not contain
- No added Sugar, Yeast, Preservatives, Artificial Flavors or Colors.
- Gluten free
- Storage
- Store at room temperature.
Source: label statements in DSLD label 258475.
What else is on the label?
Other ingredients: Cellulose, Croscarmellose Sodium, Stearic Acid, Kelp, Contains Less Than 2% of.
Seals and symbols as the label prints them (the maker's; a certifier's own list confirms a seal): Guaranteed quality Laboratory tested.
How many labels does MgO-400 have?
One label is on file, entered on January 22, 2022.
- Label 258475 (current) Entered January 22, 2022 · on the market · 90 tablets · UPC 7 40985 27072 1
DSLD also links this label to: MgO 400 mg (image difference, same product).
Source: DSLD label entry and market events, version 9.4.0 (labels entered through September 25, 2025).
Who makes it?
The label names 21st Century HealthCare, Inc. (manufacturer), Tempe, AZ. All 21st Century products.