Evidence explainerMagnesiumMagnesium glycinateMagnesium L-threonateMagnesium malate
Best Magnesium Supplement 2026: Ranked by Form, Label Dose vs Studied Dose, Testing and Cost per 100 mg
There is no single best magnesium; there is a best form for each goal. We ranked three products on our brand rubric: does the form have trials for your goal, does the label match the studied dose, how is it tested, and what 100 mg of elemental magnesium costs.
Key takeaways
- Best all-round and for sleep: a magnesium bisglycinate at 300 mg elemental per serving, close to the 250 mg dose that modestly improved insomnia scores in a 2025 trial [1][5].
- Best for focus: Magtein magnesium L-threonate at 2 g of compound (about 144 mg magnesium), the dose used in a 2025 cognition trial; it costs the most per milligram [2][6].
- Best value per milligram: magnesium malate, at roughly 11 cents per 100 mg, though malate itself has no positive form-specific trial [7][8].
- For constipation, none of these: the laxative trials used magnesium oxide [9].
- Keep supplemental magnesium at or under 350 mg a day unless a clinician advises more, and ask first if you have kidney disease [4].
The evidence, graded
Pulled from our monograph evidence tables. Grades follow our evidence-grading policy.
- Grade CImprovedInsomnia severityInsomnia Severity Index fell 3.9 points versus 2.3 with placebo (p = 0.049); a small effect (Cohen's d = 0.2). No differences in other psychological outcomes.
- Grade CImprovedOverall cognitive performanceGreater improvement than placebo on the NIH Toolbox total cognition composite (p = 0.043) and reaction time; no difference on Raven's matrices.
- Grade CMixedSleep qualityRing-measured deep and REM sleep scores and several self-rated daytime measures improved versus placebo. In a 6-week trial of 2 g/day (n=100), ring-measured sleep did not differ and only some self-rated measures improved, so results are mixed.
- No effectNo effectFibromyalgia pain and tendernessNo clear treatment effect in the blinded, fixed-dose phase. Pain scores fell in the open-label, higher-dose phase, which had no placebo control.
How we ranked them
We used the same four checks as our brand reviews. Form evidence: is there a randomized trial of this form for the goal? Label vs studied dose: does one serving deliver the amount the trial used? Testing: is there an independent certification or a published certificate of analysis? Cost: price per 100 mg of elemental magnesium at the one-time price on the seller's page, checked October 11, 2026 [5][6][7].
Elemental magnesium is the number that matters. NIH notes that the Supplement Facts panel lists elemental magnesium, not the weight of the whole compound, so 2 g of threonate and 3 g of bisglycinate deliver very different amounts [4].
The ranking
Each product was priced on its seller's own page on October 11, 2026. Partner links appear only for brands with an active program [5][6][7]:
- Supersmart Magnesium Bisglycinate (Albion TRAACS), our top pick: 300 mg elemental magnesium per 4 capsules, $39.00 for 30 servings, about 43 cents per 100 mg, with a certificate of analysis on the product page [5]. It matches the 250 mg bisglycinate trial dose [1].
- Supersmart Magnesium Threonate (Magtein): 144 mg magnesium from 2,000 mg Magtein per 3 capsules, $73.00 for 30 servings, about $1.69 per 100 mg [6].
- Supersmart Magnesium Malate, cheapest per milligram: 320 mg magnesium per 2 tablets, $22.00 for 60 servings, about 11 cents per 100 mg [7]. Malate has no positive trial of its own [8].
- Also sold at the 2 g Magtein trial dose: ProHealth Brain-Mag Pro and Momentous Magnesium L-Threonate. Their partner programs are pending, so we name them without links or prices for now [2].
Best magnesium by goal
For sleep, bisglycinate has the most direct trial: in 155 adults with poor sleep, 250 mg a day for 4 weeks lowered Insomnia Severity Index scores slightly more than placebo, a small effect [1]. Threonate also has sleep data: in an 80-person trial run by the ingredient's distributor, 1 g a day improved ring-measured deep and REM sleep scores [3]. More in magnesium for sleep.
For focus and memory, a 100-person 2025 trial found 2 g a day of Magtein improved a composite cognition score versus placebo, with no difference on a reasoning test [2]. It is the only form here with a cognition trial.
For specific symptoms, see magnesium for leg cramps, magnesium for migraines and magnesium for anxiety. For constipation, magnesium oxide matched senna in a placebo-controlled trial, and the gentle chelates above are the wrong tool [9]; see magnesium for constipation.
Best magnesium for women
No form has been compared head to head in women. Women need 310 to 320 mg of magnesium a day from all sources, versus 400 to 420 mg for men, and the 350 mg supplement upper limit is the same for both [4]. A 300 mg bisglycinate serving fits under that limit on its own [4][5]. Perimenopausal sleep problems are covered in the 3 a.m. waking guide.
Safety and interactions
Supplemental magnesium above 350 mg a day commonly causes diarrhea, and people with impaired kidney function are at risk of magnesium build-up [4]. Magnesium binds tetracycline and quinolone antibiotics and oral bisphosphonates: take those antibiotics at least 2 hours before or 4 to 6 hours after magnesium, and keep bisphosphonates at least 2 hours apart from it [4]. Check your medicines in the interaction checker and do the label maths in how much magnesium is too much.
Quick answers
What is the best form of magnesium?
It depends on the goal: bisglycinate for general use and sleep, threonate (Magtein) for focus, oxide for constipation [1][2][9].
What is the best magnesium glycinate brand?
In our ranking, Supersmart's TRAACS bisglycinate delivers 300 mg elemental magnesium per serving at about 43 cents per 100 mg, with a published certificate of analysis [5].
Is magnesium threonate worth the price?
Only if focus is the goal. It is the one form with a cognition trial, but Magtein threonate costs roughly 4 times more per 100 mg of magnesium than bisglycinate at the prices we checked [2][5][6].
How much magnesium should I take a day?
Adults need 310 to 420 mg a day from all sources, and supplements should stay at or under 350 mg a day unless a clinician advises otherwise [4].
Keep reading
Related articles
- How Much Magnesium Is Too Much? The 350 mg Rule, the Label Trap and Who Should Be Careful
- Magnesium for Constipation: Oxide Matched Senna in a Placebo Trial, With One Kidney Warning
- Magnesium for Leg Cramps: What Cochrane Found in Older Adults and in Pregnancy
- Magnesium for Migraines: The 600 mg Dose, the Guideline Rating and the Diarrhea Trade-Off
Stacks that use it
Browse the full Supplement & Nutrient Encyclopedia or all supplement articles.
Where to buy Magnesium
Products from brands we partner with that contain Magnesium. Listing a product is not a claim that it works; check the amount per serving against the doses studied above, and the label for other ingredients.
- SupersmartPaid linkMagnesium Bisglycinate (Albion TRAACS)4 capsules: 3,000 mg magnesium bisglycinate chelate providing 300 mg elemental magnesium; 30 servingsShop at Supersmart (opens in new tab)Price and label checked 2026-10-11 on the brand’s site.
Partner links may earn us a commission. Learn more
Get 15% off with SMART026 (opens in new tab)15% off with code SMART026
Partner links may earn us a commission. Learn more
- Supersmart’s own terms and exclusions apply at checkout.
- 20% applies when 3 or more products ship on auto-delivery to the same address.
- The code discount and Subscribe & Save are separate offers; we don’t claim they combine.
- Offer terms from Supersmart’s site and its affiliate program, checked Oct 8, 2026. Offers can change; the brand's checkout is final.
- SupersmartPaid linkMagnesium Threonate (Magtein)3 capsules: 2,000 mg Magtein magnesium L-threonate providing 144 mg elemental magnesium; 30 servingsShop at Supersmart (opens in new tab)Price and label checked 2026-10-11 on the brand’s site.
Partner links may earn us a commission. Learn more
Get 15% off with SMART026 (opens in new tab)15% off with code SMART026
Partner links may earn us a commission. Learn more
- Supersmart’s own terms and exclusions apply at checkout.
- 20% applies when 3 or more products ship on auto-delivery to the same address.
- The code discount and Subscribe & Save are separate offers; we don’t claim they combine.
- Offer terms from Supersmart’s site and its affiliate program, checked Oct 8, 2026. Offers can change; the brand's checkout is final.
- SupersmartPaid linkMagnesium Malate2 tablets: 1,600 mg dimagnesium malate providing 320 mg elemental magnesium; 60 servingsShop at Supersmart (opens in new tab)Price and label checked 2026-10-11 on the brand’s site.
Partner links may earn us a commission. Learn more
Get 15% off with SMART026 (opens in new tab)15% off with code SMART026
Partner links may earn us a commission. Learn more
- Supersmart’s own terms and exclusions apply at checkout.
- 20% applies when 3 or more products ship on auto-delivery to the same address.
- The code discount and Subscribe & Save are separate offers; we don’t claim they combine.
- Offer terms from Supersmart’s site and its affiliate program, checked Oct 8, 2026. Offers can change; the brand's checkout is final.
References
- [1]Magnesium Bisglycinate Supplementation in Healthy Adults Reporting Poor Sleep: A Randomized, Placebo-Controlled Trial. Nature and Science of Sleep, 2025.
- [2]The effects of magnesium L-threonate (Magtein(®)) on cognitive performance and sleep quality in adults: a randomised, double-blind, placebo-controlled trial, 2025.
- [3]Magnesium-L-threonate improves sleep quality and daytime functioning in adults with self-reported sleep problems: A randomized controlled trial, 2024.
- [4]Magnesium: Fact Sheet for Health Professionals (updated January 6, 2026; accessed October 11, 2026). NIH Office of Dietary Supplements, 2026.
- [5]Magnesium Bisglycinate, 120 veg. caps (price and Supplement Facts, checked October 11, 2026). Supersmart, 2026.
- [6]Magnesium Threonate (Magtein) (price and Supplement Facts, checked October 11, 2026). Supersmart, 2026.
- [7]Magnesium Malate (price and Supplement Facts, checked October 11, 2026). Supersmart, 2026.
- [8]Treatment of fibromyalgia syndrome with Super Malic: a randomized, double blind, placebo controlled, crossover pilot study, 1995.
- [9]Senna Versus Magnesium Oxide for the Treatment of Chronic Constipation: A Randomized, Placebo-Controlled Trial. American Journal of Gastroenterology, 2021.