Magnesium for Sleep: Small Effects in Trials, and Which Form Was Tested
Magnesium shortened time to fall asleep in small trials of older adults, and bisglycinate and L-threonate each have one or two placebo-controlled sleep trials. The effects were small, and no form has been tested head to head.
By Kymata Health Editorial Published Last checked
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Quick pick
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Momentous Magnesium Bisglycinate, 60 capsules
from Momentous
Its name matches magnesium glycinate (bisglycinate), one of the forms compared in our Forms table.
Label: 2 capsules: 200 mg magnesium (as magnesium bisglycinate).
Best for regular use: $12.74 on subscription vs $16.99 one-time (checked Oct 15, 2026).
Key takeaways
From 5 sources- In older adults with insomnia, oral magnesium shortened time to fall asleep by 17.4 minutes versus placebo across 3 small trials, with low to very low quality evidence1.
- Magnesium bisglycinate providing 250 mg of magnesium a day lowered insomnia severity a little more than placebo over 4 weeks in 155 adults who slept poorly2.
- Magnesium L-threonate improved ring-measured deep and REM sleep scores in a 21-day trial, but a 6-week trial found no difference in ring-measured sleep34.
- Each form was tested against placebo, not against other forms, so no trial shows which magnesium is best for sleep123.
- The adult upper limit for magnesium from supplements and medicines is 350 mg a day5.
What this article covers
3 evidence profilesThe evidence, graded
Pulled from the trial tables in our evidence profiles. Grades follow our evidence-grading policy.
Graded findings
3 rows- CGrade CTime to fall asleep (older adults)Improved Sleep onset latency was 17.4 minutes shorter than placebo; total sleep time rose 16 minutes but not significantly. Trials were at moderate-to-high risk of bias; evidence quality low to very low.Magnesium · Meta-analysis · n=151 · 2021 · PMID 33865376
- CGrade CInsomnia severityImproved Insomnia 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.Magnesium glycinate · RCT · n=155 · 2025 · PMID 40918053
- CGrade CSleep qualityMixed Ring-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.Magnesium L-threonate · RCT · n=80 · 2024 · PMID 39252819
Where these trials agree: Magnesium glycinate and sleep, counted row by row in the Consensus finder.
What the sleep trials found
A 2021 meta-analysis pooled 3 randomized trials of older adults with insomnia. Magnesium cut the time to fall asleep by 17.4 minutes compared with placebo, while total sleep time rose 16 minutes, a change that was not statistically significant1. The trials were small and at moderate to high risk of bias1.
In a 2025 trial of 155 healthy adults aged 18 to 65 who reported poor sleep, magnesium bisglycinate at 250 mg of elemental magnesium a day lowered the Insomnia Severity Index by 3.9 points, against 2.3 points with placebo, after 4 weeks2. The authors rated it a small effect, and other psychological outcomes did not differ2.
For magnesium L-threonate, a 21-day trial in 80 adults aged 35 to 55 found better ring-measured deep and REM sleep scores and better self-rated daytime functioning than placebo3. A 6-week trial of 2 g a day in 100 adults found no difference in ring-measured sleep, and only some self-rated measures improved4.
Glycinate, threonate or another form?
The bisglycinate trial dosed 250 mg of elemental magnesium a day2. The threonate trials dosed the whole compound, 1 g or 2 g a day, and 1 g supplies only about 83 mg of magnesium34. The older-adult meta-analysis pooled trials that used different forms1.
Because none of these trials compared forms directly, the choice between them comes down to dose, tolerance and price rather than proven sleep differences123. Compare the forms on the magnesium glycinate, magnesium L-threonate and magnesium pages, or read glycinate vs citrate and the best magnesium supplement by form.
Reading the label: elemental magnesium
A label may give the weight of the whole compound, the elemental magnesium it provides, or both. The adult upper limit of 350 mg a day counts elemental magnesium from supplements and medicines only, not magnesium in food5.
The arithmetic is worked through in magnesium upper limit and label math.
Who should be careful
If your kidneys are impaired, excess magnesium can build up, whatever the form5. Magnesium binds tetracycline and quinolone antibiotics and oral bisphosphonates such as alendronate, so doses need to be spaced apart; a pharmacist can set the timing5.
Too much magnesium from supplements commonly causes loose stools, nausea or cramps5.
Other sleep supplements with trial data
Magnesium is one of several supplements studied for sleep. See apigenin for sleep, melatonin dose and timing, tart cherry for sleep and valerian root, or the sleep and magnesium hub.
Quick answers
Common questions
4 answersWhat is the best magnesium for sleep?
How much magnesium was used for sleep in trials?
Does magnesium help older adults sleep?
In 3 small trials of older adults with insomnia, magnesium shortened the time to fall asleep by about 17 minutes, but total sleep time did not change significantly1.
Keep reading
Full evidence profiles
Every graded study, studied doses, interactions and safety- MineralMagnesium glycinateMagnesium bound to the amino acid glycine (about 14% magnesium by weight); studied in small trials for sleep, asthma/COPD and mood.AGrade A
- MineralMagnesiumEssential mineral involved in over 300 enzyme systems; sold as glycinate, citrate, threonate, malate, taurate, oxide and other salts.AGrade A
- MineralMagnesium L-threonateMagnesium salt of L-threonic acid (about 8% magnesium by weight), studied for cognition and sleep in small RCTs.CGrade C
Related articles
4 articles- ArticleMagnesium for Anxiety: Suggestive Trials, Poor Quality, and What Glycinate Has (Not) ShownDoes magnesium help anxiety?
- ArticleMagnesium Glycinate vs Citrate: The Calm One, the Bathroom One, and What the Label Really HoldsMagnesium glycinate vs citrate: which is better?
- ArticleThe Sleepy Girl Mocktail: What Tart Cherry and Magnesium Can and Cannot Do for SleepDoes the sleepy girl mocktail actually help you sleep?
- ArticleAshwagandha Interactions: Thyroid Medicine, Sedatives, SSRIs, Alcohol, Magnesium and L-TheanineWhat does ashwagandha interact with?
More on Supplements and vitamins
7 pages- TopicSupplements and vitamins: every page
- PreviousConsensus finderPick a supplement and an outcome: the graded trial rows on each side, and where they disagree.
- In this topicMagnesium Glycinate vs L-Threonate: The Sleep Form, the Brain Form, and Less Magnesium Than You ThinkThreonate is sold as the magnesium that reaches the brain; glycinate as the calm bedtime form.
- In this topicMagnesium L-Threonate for Memory and Brain Fog: What the Human Trials Show, and Who Paid for ThemThe “brain magnesium” story started in rats.
- In this topicMCT Oil vs Coconut Oil: Related Fats, Very Different Results in the TrialsMCT oil and coconut oil are often sold as if interchangeable, but the coconut oil tested in a ketone trial held only about 8% of the C8 and C10 fats that make up most of MCT oil.
- ToolEvidence-graded supplement stacks
- TopicsBrowse all topics
Browse the full Supplement & Nutrient Encyclopedia or all supplement articles.
Where to buy Magnesium glycinate
Products from brands we partner with that contain Magnesium glycinate. Check the amount per serving against the doses studied, and the label for other ingredients.
Magnesium glycinate products from partner brands
6 products Paid links · we earn a commission- Quick pickMomentousMomentous Magnesium Bisglycinate, 60 capsulesWe use this brand at home. What we useSubscribe & save 25%
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2 capsules: 200 mg magnesium (as magnesium bisglycinate); 30 servings
$16.99one-time$12.74subscribeChecked Oct 15, 2026 - SupersmartMagnesium Bisglycinate (Albion TRAACS)5% off with the Supersmart newsletterGet 5% off with the newsletter (paid link, opens in new tab)
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4 capsules: 3,000 mg magnesium bisglycinate chelate providing 300 mg elemental magnesium; 30 servings
$39.00one-time$33.15subscribeChecked Oct 11, 2026 - HerbsProNOW Foods Magnesium Glycinate, 90 Tabs
2 tablets: 200 mg elemental magnesium from magnesium bisglycinate (Albion)
$11.24one-timeChecked Oct 14, 2026 - Dr. TobiasDr. Tobias Magnesium Bisglycinate (120 capsules)
1 vegetable capsule: 200 mg magnesium as magnesium bisglycinate chelate buffered with magnesium oxide (Albion TRAACS)
$29.99one-timeChecked Oct 14, 2026 - Botanic ChoiceBotanic Choice Magnesium Glycinate, 240 mg, 60 capsules
2 capsules: 240 mg magnesium (as Albion magnesium bisglycinate chelate buffered with magnesium oxide); 30 servings; gelatin capsule
$20.00one-timeChecked Oct 19, 2026 - Organics OceanOrganics Ocean Pure Magnesium Glycinate, 90 capsules
3 capsules: 275 mg magnesium (Chelamax, from 1,250 mg magnesium glycinate) and 2 mg zinc; 30 servings. An independent lab test (Lead Safe Mama, July 2025) found lead and cadmium in this product.
$35.00one-time$29.99subscribeChecked Oct 19, 2026
References
5 sources. Numbers in the text link here.
Sources cited in this article
5 sources- 1Oral magnesium supplementation for insomnia in older adults: a Systematic Review & Meta-Analysis.BMC Complement Med Ther, 2021 · PMID 33865376
- 2Magnesium Bisglycinate Supplementation in Healthy Adults Reporting Poor Sleep: A Randomized, Placebo-Controlled Trial.Nat Sci Sleep, 2025 · PMID 40918053
- 3Magnesium-L-threonate improves sleep quality and daytime functioning in adults with self-reported sleep problems: A randomized controlled trial.Sleep Med X, 2024 · PMID 39252819
- 4The effects of magnesium L-threonate (Magtein®) on cognitive performance and sleep quality in adults: a randomised, double-blind, placebo-controlled trial.Front Nutr, 2025 · PMID 41601871
- 5Magnesium: Fact Sheet for Health Professionals (updated January 6, 2026)NIH Office of Dietary Supplements, 2026
Magnesium glycinate and other dietary supplements are not intended to diagnose, treat, cure or prevent any disease, and these statements have not been evaluated by the FDA. Talk to your clinician or pharmacist before starting a supplement, especially if you take prescription medicines. Product links on this page are paid partner links.