Magnesium is involved in over 300 enzymatic reactions in the body, yet an estimated 48% of Americans are deficient. The problem is that most magnesium supplements use cheap forms (magnesium oxide) with poor bioavailability. We tested five products across different forms — glycinate, malate, L-threonate, citrate, and oxide — to give you a definitive answer on which form to use and which products deliver it best.
Panel Pick — Best Magnesium
Thorne Magnesium Bisglycinate
Sleep quality and general magnesium repletion · Score: 9.3 · $28.00 / 60 servings
| Product | Overall | Efficacy | Ingredients | Experience | Value | Best For | Price |
|---|---|---|---|---|---|---|---|
| 9.3 | 9.5 | 9.8 | 8.9 | 9.0 | Sleep quality and general magnesium repletion | $28.00 / 60 servings | |
| 9.0 | 9.3 | 9.5 | 8.5 | 7.8 | Cognitive function and brain health (crosses blood-brain barrier) | $54.00 / 30 servings | |
| 8.7 | 8.9 | 9.2 | 8.3 | 8.8 | Muscle function and energy production | $24.00 / 90 servings | |
| 7.5 | 8.0 | 7.2 | 7.8 | 8.0 | Occasional use for stress and constipation relief | $22.95 / 30 servings | |
| 4.2 | 3.5 | 4.0 | 4.8 | 5.5 | Nothing — magnesium oxide has ~4% bioavailability. Spend $18 more on glycinate. | $9.99 / 90 servings |
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How We Ranked These
Every product was purchased at retail price and tested for a minimum of 8 weeks by at least one panelist. Scores reflect our five-pillar methodology: Efficacy & Performance (35%), Ingredient Quality & Safety (25%), User Experience & Design (20%), Brand & Mission (10%), and Value & Investment (10%). No brand was given advance notice of testing or an opportunity to influence the outcome.
Read the full methodology →