Best Magnesium Supplements, Scored on a Public Rubric
Magnesium is the most-searched supplement on Amazon, and for good reason: roughly 48% of US adults consume below the Recommended Dietary Allowance, according to the NIH Office of Dietary Supplements. Choosing a magnesium supplement is more complicated than picking a brand — form (glycinate, citrate, oxide, malate, threonate), elemental dose, and third-party testing all change what you actually get. This roundup scores seven widely-available Amazon products on our 6-metric rubric so you can see exactly why we rank them the way we do.
At-a-glance
| Product | Best for | Score |
|---|---|---|
| Thorne — Basic Nutrients Magnesium Bisglycinate | Overall pick — third-party testing + clinical-grade transparency | 8.7/10 |
| Doctor's Best — High Absorption Magnesium Glycinate/Malate | Best value for glycinate at scale | 8.2/10 |
| NOW Foods — Magnesium Citrate | Budget choice with third-party testing | 7.8/10 |
| Moon Juice — Magnesi-Om | Best drink-powder option — convenience + dual form | 7.2/10 |
| Life Extension — Magtein Magnesium L-Threonate | L-threonate form — specifically studied for brain uptake | 7.7/10 |
| Nutricost — Magnesium Glycinate | Simple, transparent, lowest total cost | 7.7/10 |
| Nested Naturals — Triple Magnesium Complex | Blended-form option for people unsure which form | 7.2/10 |
How we scored
Every product below is scored on six metrics, 0-10 each, with the weighting described on how we review. The criteria specific to this category:
- Chelated or organic forms (glycinate, citrate, malate) prioritized over oxide, which has roughly 4% absorption in published studies.
- Elemental magnesium disclosed on the label — not just mg of the compound.
- Third-party testing evidence (USP, NSF, Informed Sport, or published certificate of analysis).
- Filler and additive disclosure — no undisclosed proprietary blends.
- Price per gram of elemental magnesium, not price per bottle.
- Brand transparency about sourcing, testing, and contamination results.
What to know before buying
- Target 200-400 mg elemental magnesium per day from supplements, combined with dietary sources. Anyone with kidney disease should consult a doctor before supplementing.
- Glycinate is the most-studied form for low gastrointestinal side effects. Citrate is effective and inexpensive but has a laxative effect at higher doses. Oxide is cheap but poorly absorbed.
- Gummies rarely disclose elemental dose clearly and often contain 2-4g of sugar per serving — not a good value for mineral supplementation.
Our picks
Thorne — Basic Nutrients Magnesium Bisglycinate
Key specs: 135mg elemental magnesium bisglycinate, 60 capsules, NSF-certified facility
Pros
- NSF Certified for Sport — one of the highest third-party testing bars
- Fully-chelated bisglycinate, well-tolerated at recommended dose
- Label discloses elemental mg and compound mg separately
- Published heavy-metal testing summaries on brand site
Cons
- Premium price per elemental gram
- Smaller per-capsule dose means multiple capsules for 300-400mg target
Thorne — Basic Nutrients Magnesium Bisglycinate
- Third-party testing10/10
- Bioavailability9/10
- Clinical evidence8/10
- Value6/10
- Brand transparency10/10
- Form & absorption9/10
Doctor's Best — High Absorption Magnesium Glycinate/Malate
Key specs: 100mg elemental magnesium, 240 tablets, chelated form (TRAACS)
Pros
- TRAACS chelate is a named, researched patent — not generic
- Inexpensive per elemental gram
- USP-verified certificate available on manufacturer site
- High capsule count per bottle — cost-effective for daily use
Cons
- Capsule size is large and some users find it hard to swallow
- Contains stearic acid as a binding agent (disclosed)
Doctor's Best — High Absorption Magnesium Glycinate/Malate
- Third-party testing8/10
- Bioavailability8/10
- Clinical evidence7/10
- Value10/10
- Brand transparency8/10
- Form & absorption8/10
NOW Foods — Magnesium Citrate
Key specs: 200mg elemental magnesium citrate, 250 tablets, USP-verified
Pros
- NOW maintains an in-house ISO-certified analytical lab and publishes COAs
- Very affordable per elemental gram
- Widely available with consistent batch quality
Cons
- Citrate can have a mild laxative effect at doses above 400mg
- Tablets are coated with vegetable glaze — not an issue but less clean than capsule-only
NOW Foods — Magnesium Citrate
- Third-party testing8/10
- Bioavailability7/10
- Clinical evidence7/10
- Value10/10
- Brand transparency8/10
- Form & absorption7/10
Moon Juice — Magnesi-Om
Key specs: 311mg elemental magnesium (gluconate + citrate + L-threonate), 28 servings
Pros
- Combines three forms including L-threonate, which crosses the blood-brain barrier
- Berry powder format is a nicer evening routine than capsules for many people
- Clear elemental-dose labeling
Cons
- Significantly more expensive per elemental gram than capsule options
- Less extensive public third-party testing data compared to Thorne or NOW
Moon Juice — Magnesi-Om
- Third-party testing6/10
- Bioavailability9/10
- Clinical evidence7/10
- Value5/10
- Brand transparency7/10
- Form & absorption9/10
Life Extension — Magtein Magnesium L-Threonate
Key specs: 2,000mg of Magtein (144mg elemental magnesium), 90 capsules
Pros
- Magtein is the patented L-threonate form used in the original published studies
- Life Extension publishes batch testing data
- Targeted to a specific use case — cognition research literature
Cons
- Expensive per elemental gram compared to glycinate
- Low elemental dose per serving — would need to stack with another form for general repletion
Life Extension — Magtein Magnesium L-Threonate
- Third-party testing8/10
- Bioavailability8/10
- Clinical evidence8/10
- Value5/10
- Brand transparency9/10
- Form & absorption8/10
Nutricost — Magnesium Glycinate
Key specs: 420mg elemental magnesium per 2-cap serving, 240 capsules, Informed-Sport-tested line
Pros
- Label clearly breaks down elemental vs compound mg
- Informed-Sport certification on selected batches
- Cost-effective per elemental gram
Cons
- Third-party testing coverage is batch-selective, not all-batch
- Larger dose per serving may cause GI effects in sensitive users — split the dose
Nutricost — Magnesium Glycinate
- Third-party testing7/10
- Bioavailability8/10
- Clinical evidence7/10
- Value9/10
- Brand transparency7/10
- Form & absorption8/10
Nested Naturals — Triple Magnesium Complex
Key specs: 300mg elemental magnesium (glycinate + malate + citrate), 180 capsules
Pros
- Combines three well-absorbed forms in a single capsule
- Non-GMO Project Verified and Informed Sport on published batches
- Moderate per-elemental-gram cost
Cons
- Doesn't break down how much comes from each form on the label
- Blended formulas make it harder to attribute GI effects if they occur
Nested Naturals — Triple Magnesium Complex
- Third-party testing7/10
- Bioavailability8/10
- Clinical evidence7/10
- Value7/10
- Brand transparency6/10
- Form & absorption8/10
Frequently asked questions
It depends on the goal. Magnesium glycinate is the most-studied form for low GI side effects and general daily repletion. Citrate is effective and cheap but can have a laxative effect. L-threonate is specifically researched for crossing the blood-brain barrier. Oxide is inexpensive but has poor absorption (around 4% in published data) and is not recommended for supplementation.
Related reading
Sources
- Magnesium — Fact Sheet for Health Professionals — NIH Office of Dietary Supplements, 2022
- Bioavailability of US Commercial Magnesium Preparations — Magnesium Research, 2001
- The Effect of Magnesium Supplementation on Primary Insomnia in Elderly — Journal of Research in Medical Sciences, 2012
- USP Dietary Supplement Verification — US Pharmacopeia
Last verified: April 21, 2026. See our editorial policy and how we review for details on scoring and update cadence. Canonical URL: https://trustedhealthgear.com/reviews/best-magnesium-supplement.