Cheapest Magnesium (as magnesium oxide from seawater) on iHerb
Ranked by real cost per 10 mg of Magnesium (as magnesium oxide from seawater) — cheapest value first.
Prices updated Jul 25, 2026 · 9 products · Prices in USD
| # | Product | Dose | Price (USD) | Cost per 10 mg | |
|---|---|---|---|---|---|
| 1 |  | 75 mg | 28.04 | 0.042 | View on iHerb → |
| 2 |  | 75 mcg | 38.24 | 0.043 | View on iHerb → |
| 3 |  | 75 mg | 22.09 | 0.049 | View on iHerb → |
| 4 |  | 50 mg | 40.79 | 0.054 | View on iHerb → |
| 5 |  | 50 mg | 40.79 | 0.054 | View on iHerb → |
| 6 |  | 50 mg | 28.04 | 0.062 | View on iHerb → |
| 7 |  | 50 mg | 38.24 | 0.064 | View on iHerb → |
| 8 |  | 50 mg | 38.24 | 0.064 | View on iHerb → |
| 9 |  | 50 mg | 22.09 | 0.074 | View on iHerb → |
- 1Cost per 10 mg 0.042
- Dose
- 75 mg
- Servings
- 90
- Price (USD)
- 28.04
- 2Cost per 10 mg 0.043
- Dose
- 75 mcg
- Servings
- 120
- Price (USD)
- 38.24
- 3Cost per 10 mg 0.049
- Dose
- 75 mg
- Servings
- 60
- Price (USD)
- 22.09
- 4Cost per 10 mg 0.054
- Dose
- 50 mg
- Servings
- 150
- Price (USD)
- 40.79
- 5Cost per 10 mg 0.054
- Dose
- 50 mg
- Servings
- 150
- Price (USD)
- 40.79
- 6Cost per 10 mg 0.062
- Dose
- 50 mg
- Servings
- 90
- Price (USD)
- 28.04
- 7Cost per 10 mg 0.064
- Dose
- 50 mg
- Servings
- 120
- Price (USD)
- 38.24
- 8Cost per 10 mg 0.064
- Dose
- 50 mg
- Servings
- 120
- Price (USD)
- 38.24
- 9Cost per 10 mg 0.074
- Dose
- 50 mg
- Servings
- 60
- Price (USD)
- 22.09
How we rank Magnesium (as magnesium oxide from seawater)
Two supplements can list the same dose per serving yet cost very differently once you account for how many servings are in the bottle. We calculate the total nutrient in each container (dose per serving × servings per container), divide the current price by that total, and rank by the resulting cost per unit. Lower is better. Because prices are refreshed automatically, this ranking reflects today's iHerb pricing rather than a snapshot from months ago.
Cost per unit is a starting point, not the whole story — the ideal form, third-party testing, and other ingredients matter too. Always check the label and consult a healthcare professional before starting a supplement.
Prices update automatically and may differ from iHerb at checkout. Rankings are based on cost per unit of the listed nutrient and are for informational purposes only — not medical advice. Links to iHerb are affiliate links.