Quick answers
- What is Magnesium oxide used for?
- The Drug Facts label of Magnesium Oxide (Westminster Pharmaceuticals, LLC) lists these uses: relieves: acid indigestion upset stomach.
- Do I need a prescription for Magnesium oxide?
- No. The products on this page are sold without a prescription (over the counter).
- Is a store brand the same as the name brand?
- Products listed together below have the same active ingredient, in the same amount and the same form, as registered with the FDA. Inactive ingredients (such as colors, flavors and fillers) and package sizes can differ. Compare the “Active ingredient” box on both packages, and ask a pharmacist if you are not sure.
- Has Magnesium oxide been recalled?
- No recall linked to these products appears in the FDA enforcement reports we use.
Drug Facts label
Every over-the-counter medicine must carry a “Drug Facts” box in the same order, set by FDA rules. Below is the label of one product for each common strength and form, quoted word for word. Your own package can differ (for example, children’s products have other directions): always follow the label on your package.
Magnesium Oxide · Westminster Pharmaceuticals, LLC
Magnesium oxide 400 mg, tablet (oral)
Active ingredient
Magnesium Oxide 400 mg (241.3 mg Elemental Magnesium)
Purpose
Antacid
Uses
relieves: acid indigestion upset stomach
Warnings
Ask a doctor before use if
you have kidney disease you are taking a prescription drug (antacids may interact with certain prescription drugs) you are pregnant or breast feeding. Do not take more than 2 tablets in a 24 hour period. May have a laxative effect.
Keep out of reach of children
Directions
take one or two antacid tablets daily. Do not exceed two tablets unless directed by a physician.
Inactive ingredients
Colloidal Silicon Dioxide, Corn Starch, Croscarmellose Sodium, Microcrystalline Cellulose, and Stearic Acid.
Questions?
Call 1-844-221-7294 M-F 9am - 5pm EST
— FDA label of Magnesium Oxide, Westminster Pharmaceuticals, LLC, effective July 6, 2026. See the official label on DailyMed →
Magnesium Oxide · Richmond Pharmaceuticals, Inc.
Magnesium oxide 420 mg, tablet (oral)
Active ingredient (In each tablet)
Magnesium Oxide 420 mg Purpose Antacid
Purpose
Antacid
Uses
Relieves:
- acid indigestion
- upset stomach
Warnings
Ask a doctor if you have: kidney disease
Ask a doctor or pharmacist before use if
you are: taking a prescription drug. Antacids may interact with certain prescription drugs. Do not take more than 2 tablets in a 24 hour period or use the maximum dosage of this product for more than two weeks, except under the advise and supervision of a physician. May have a laxative effect.
If pregnant or breast-feeding
ask a health professional before use. Keep Out of Reach of Children.
Directions
Antacid Directions:
- take 1 tablet twice a day or as directed by a physician Magnesium Supplement Directions:
- take 1 to 2 tablets daily or as directed by a physician
Inactive ingredients
croscarmellose sodium, microcrystalline cellulose, magnesium stearate
Questions?
TAMPER EVIDENT: DO NOT USE IF IMPRINTED SAFETY SEAL UNDER CAP IS BROKEN OR MISSING call 804-270-4498, 8.30 am-4.30 pm ET, Monday - Friday
— FDA label of Magnesium Oxide, Richmond Pharmaceuticals, Inc., effective December 26, 2024. See the official label on DailyMed →
Magnesium Oxide · Belleview Biosciences
Magnesium oxide 241.3 mg/1000 mg, tablet (oral)
Active ingredient
DRUG FACTS Active Ingredient (in each tablet) Purpose Magnesium Oxide 400mg (241.3mg elemental magnesium Antacid Purpose Antacid
Purpose
Antacid
Uses
relieves acid indigestion upset stomach
Warnings
Ask a doctor before use if
* you have kidney disease * you are taking a prescription drug (antacids may interact with certain prescription drugs) * you are pregnant or breast feeding
Ask a doctor or pharmacist before use if
you are taking a prescription drug. Antacids may interact with certain prescription drugs.
Keep out of reach of children
If pregnant or breast-feeding
ask a health professional before use. Do Not Take more than 2 tablets in a 24 hour period or use the maximum dosage of this product fo more than two weeks, except under the advice and supervision of a physican. May have a laxative effect.
Directions
Antacid Directions Take 1 Tablet twice a day or as directed by a physicain. Magnesium Supplement Directions: Take 1 to 2 Tablets daily or as directed by a physician.
Other information
Magnesium content per tablet: 241.3mg Store at controlled room temperature 59 o F to 86 o F (15 o C to 30 o C)
Inactive ingredients
Microcrystaline Cellulose, Sodium Starch Glycolate, Stearic Acid
Questions?
of Comments? 1-833-537-4679
— FDA label of Magnesium Oxide, Belleview Biosciences, effective April 1, 2025. See the official label on DailyMed →
This page is not medical advice. Read the label on your package, and ask a pharmacist or doctor if you are not sure a medicine is right for you, for your child, or with your other medicines.
Same medicine, other brands
Each group lists the products that have exactly the same active ingredient, in the same amount and form, as registered with the FDA (NDC Directory). A store brand in the same group has the same medicine as the name brand; inactive ingredients, flavors and package sizes can differ. Each product links to its own official label.
Magnesium oxide 400 mg · tablet (oral) · 14 products
Drug Facts for this strength and form ↑
| Brand or product name | Company on the label | Label |
|---|---|---|
| Magnesium Oxide | A-S Medication Solutions | DailyMed |
| Magnesium Oxide | Aphena Pharma Solutions - Tennessee, LLC | DailyMed |
| Magnesium Oxide | Apnar Pharma LP | DailyMed |
| Magnesium Oxide | Bryant Ranch Prepack | DailyMed |
| Magnesium Oxide | Kesin Pharma | DailyMed |
| Magnesium Oxide | Marlex Pharmaceuticals Inc | — |
| Magnesium Oxide | Method Pharmaceuticals, LLC | DailyMed |
| Magnesium Oxide | Par Health | — |
| Magnesium Oxide | Richmond Pharmaceuticals, Inc. | DailyMed |
| Magnesium Oxide | Westminster Pharmaceuticals, LLC | DailyMed |
| Magnesium Oxide 400mg | Allegiant Health | DailyMed |
Magnesium oxide 420 mg · tablet (oral) · 2 products
Drug Facts for this strength and form ↑
| Brand or product name | Company on the label | Label |
|---|---|---|
| Magnesium Oxide | Marlex Pharmaceuticals Inc. | — |
| Magnesium Oxide | Richmond Pharmaceuticals, Inc. | DailyMed |
Magnesium oxide 440 mg · tablet (oral) · 1 product
| Brand or product name | Company on the label | Label |
|---|---|---|
| Mag 440 | Allegis Pharmaceuticals, LLC | — |
Magnesium oxide 241.3 mg/1000 mg · tablet (oral) · 1 product
Drug Facts for this strength and form ↑
| Brand or product name | Company on the label | Label |
|---|---|---|
| Magnesium Oxide | Belleview Biosciences | DailyMed |
Magnesium oxide 253 mg · tablet (oral) · 1 product
| Brand or product name | Company on the label | Label |
|---|---|---|
| Magnesium Oxide | Par Health | — |
What pharmacies pay (NADAC)
The National Average Drug Acquisition Cost (NADAC) is the average price U.S. retail pharmacies paid to buy one unit of a medicine (one tablet, one mL or one gram), from a monthly survey of pharmacy invoices by the Centers for Medicare & Medicaid Services (CMS). State Medicaid programs use it to pay pharmacies.
This is not the price you pay. What you pay depends on your insurance (copay or coinsurance), your pharmacy and any discounts, and pharmacies also charge for filling a prescription. Ask your pharmacist or your health plan what your price will be.
| Strength and form | Generic or brand | Pharmacies pay |
|---|---|---|
| magnesium oxide 253 mg tablet | Generic | $0.0390 per tablet |
| magnesium oxide 400 mg tablet | Generic | $0.0354 per tablet |
NADAC list of November 4, 2026; these prices took effect on October 21, 2026. Shown only where a package’s NDC code matches the NADAC list exactly, and only for that exact strength and form: nothing is averaged across strengths. Strengths and forms not listed here have no NADAC price.
Source: NADAC (National Average Drug Acquisition Cost) 2026, data.medicaid.gov (CMS) →
Companies that sell this medicine
The company named on the package (maker or distributor), as listed in the FDA NDC Directory, with its number of over-the-counter products of this medicine.
- Bryant Ranch Prepack3 products
- Richmond Pharmaceuticals, Inc.2 products
- Aphena Pharma Solutions - Tennessee, LLC2 products
- Par Health2 products
- Marlex Pharmaceuticals Inc2 products
- Method Pharmaceuticals, LLC1 product
- A-S Medication Solutions1 product
- Allegis Pharmaceuticals, LLC1 product
- Allegiant Health1 product
- Apnar Pharma LP1 product
- Westminster Pharmaceuticals, LLC1 product
- Belleview Biosciences1 product
- Kesin Pharma1 product
Recalls
No recall linked to these products (by their NDC code or label) appears in the FDA enforcement reports.
Sources
- Drug labeling (SPL, openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026
- NDC Directory (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026
- Drug recall enforcement reports (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 27, 2026, retrieved October 31, 2026
- FDA rule for the Drug Facts label (21 CFR 201.66)
Only medicines marketed under FDA rules for nonprescription drugs (an FDA monograph or an FDA approval) are listed. Homeopathic products are not listed: the FDA does not evaluate them for safety or effectiveness.