Last updated: March 2026
How Much Does Magnesium Oxide (Mag-Ox) Cost?
Cost Breakdown by Type
| Type / Procedure | Without Insurance | With Insurance |
|---|---|---|
| Magnesium Oxide 400mg Tablet | $4 – $8 | $0 – $3 |
| Magnesium Oxide 400mg Capsule | $4 – $10 | $0 – $5 |
What Affects the Cost
- Brand-name vs. generic availability
- Insurance formulary tier placement
- Pharmacy choice (retail vs. mail-order vs. Costco)
- Manufacturer savings cards and coupons
- Dosage and quantity prescribed
- Geographic location
Insurance Coverage
Typical coverage: Tier 1 generic — covered on most plans; also available OTC
Most insurance plans use a tiered formulary: Tier 1 (generic) $0-$15 copay, Tier 2 (preferred brand) $25-$75, Tier 3 (non-preferred brand) $50-$150, Tier 4 (specialty) $100-$500+. Prior authorization may be required for certain medications. Step therapy may require trying cheaper alternatives first.
How to Save Money
- Always ask for generic when available — saves 50-90%
- Use GoodRx, RxSaver, or similar discount cards
- Costco pharmacy is open to non-members and often has lowest prices
- Mark Cuban's Cost Plus Drugs offers transparent low pricing
- Manufacturer patient assistance programs provide free medication to qualifying patients
- HSA/FSA funds can cover medication costs tax-free
Related Procedures & Costs
Frequently Asked Questions
Magnesium oxide costs $4 to $10 for a 30-day supply without insurance. It is one of the most affordable mineral supplements.
Magnesium oxide is used to treat and prevent low magnesium levels, which can occur with certain diuretics, alcohol use, or GI conditions. It is also used as an antacid and laxative.
Magnesium oxide has the highest magnesium content per tablet but lower absorption than other forms like magnesium citrate or glycinate. For deficiency correction, the higher dose often compensates for lower bioavailability.