Magnesium glycinate for sleep is a common question, and the research gives a modest answer. A 2025 randomized trial in healthy adults who reported poor sleep found a small improvement in sleep scores with magnesium bisglycinate compared with placebo, while broader reviews describe the evidence as mixed. MAXIS Magnesium Glycinate is labeled for normal muscle and nerve function and energy production, not for sleep, so this article covers what the ingredient research measured and how to think about it.†
Below: what magnesium does in the body, what the trials found, why glycine may matter, when to take it, and the safety limits that apply to any magnesium supplement.
Key takeaways
- In a 4-week trial of 155 healthy adults reporting poor sleep, 250 mg of magnesium from magnesium bisglycinate improved a sleep-difficulty score slightly more than placebo. The effect size was small.
- Other measures in that trial, including a single-item sleep quality rating, perceived stress and mood, did not differ from placebo.
- A systematic review of nine studies found an association between magnesium status and sleep quality in observational data, but inconsistent results in randomized trials.
- The adult upper limit for magnesium from supplements is 350 mg a day. Food magnesium does not count toward it.
- Roughly half of Americans get less magnesium from food than they need, which may shape who notices a difference.
What magnesium does, and why sleep comes up
Magnesium is a cofactor in hundreds of enzyme systems. It is involved in normal muscle and nerve function, energy production and protein synthesis, which is why it comes up so often in conversations about relaxation and rest. Interest is high; the trial evidence is still thin.
Intake is a real issue. According to the NIH Office of Dietary Supplements, national survey data show that 48% of Americans take in less magnesium from food and beverages than the estimated average requirement. The recommended daily amount is 400 to 420 mg for adult men and 310 to 320 mg for adult women, depending on age. Food closes much of that gap: an ounce of roasted pumpkin seeds has about 156 mg, an ounce of dry-roasted almonds about 80 mg, and half a cup of boiled spinach about 78 mg.
Magnesium glycinate is magnesium bound to glycine, an amino acid. It is often chosen because it is less likely to loosen stools than some other forms. Our comparison of magnesium glycinate vs. citrate vs. oxide explains the differences.
Magnesium glycinate for sleep: what the 2025 trial measured
The most relevant study is a randomized, placebo-controlled trial published in 2025 in Nature and Science of Sleep. Researchers enrolled 155 adults aged 18 to 65 who described themselves as healthy but had reported poor sleep for more than four weeks. People taking sleep- or mood-affecting medication or already taking more than 200 mg of supplemental magnesium were excluded.
Participants took two capsules 30 to 60 minutes before bed for four weeks. Together the capsules provided 250 mg of elemental magnesium as magnesium bisglycinate, which also delivered about 1.5 grams of glycine. The control group took cellulose capsules.
| Measure | Magnesium bisglycinate | Placebo |
|---|---|---|
| Change in sleep-difficulty score at week 4 | −3.9 points | −2.3 points |
| Relative reduction from baseline | 28% | 18% |
| Single-item sleep quality rating | Both groups improved; difference not significant | |
| Perceived stress and mood | No difference between groups | |
The difference in the main score reached statistical significance (p = 0.049), but the authors described the effect as small (Cohen's d of 0.2). An exploratory analysis suggested people who rated their dietary magnesium intake as lower responded more, though the diet tool was not validated. No serious adverse events were reported. The study was funded internally by Leibniz University Hannover; one author manages a contract research organization that receives funding from nutraceutical companies.
In plain terms: a real but modest signal, in a short trial, in adults whose sleep was below par but who were otherwise healthy.
What the wider research says
A 2023 systematic review in Biological Trace Element Research pulled together nine cross-sectional, cohort and randomized studies covering 7,582 people. Observational studies tended to link better magnesium status with better sleep quality. The randomized trials, however, gave inconsistent results, and the authors called for larger, well-designed trials lasting longer than 12 weeks.
There is also a separate thread of research on glycine itself. In a 2007 study, volunteers with persistently unsatisfying sleep took 3 grams of glycine before bed and reported better subjective sleep quality and less daytime sleepiness. That dose is larger than the glycine in the 2025 magnesium trial, and supplement labels usually list only the elemental magnesium in magnesium glycinate, not the glycine.
When to take magnesium glycinate
No official guideline sets a time of day. The 2025 trial gave magnesium 30 to 60 minutes before bed, so people interested in an evening routine often follow that pattern. Others split their dose across the day to reduce the chance of stomach upset. Consistency matters more than the clock.
Timing does matter with some medications. The NIH advises taking magnesium at least 2 hours apart from oral bisphosphonates, and taking tetracycline or quinolone antibiotics at least 2 hours before or 4 to 6 hours after a magnesium supplement.
Where MAXIS Magnesium Glycinate fits
MAXIS Magnesium Glycinate provides 400 mg of elemental magnesium from magnesium glycinate in three vegan capsules, about 133 mg per capsule, with 60 servings per bottle. It supports normal muscle and nerve function and is required for energy production and protein synthesis.† The label does not set a time of day.
Be aware that a full serving of 400 mg is above the 350 mg adult upper limit for magnesium from supplements. That limit exists mainly because high supplemental doses can cause diarrhea, nausea and cramping. Each capsule is about 133 mg, so you and your healthcare provider can choose a lower amount. Also count magnesium from other products: one stick of MAXIS Hydrate adds 100 mg, as explained in our guide to electrolytes vs. sports drinks. If you are interested in other ingredients studied for rest, see Ashwagandha for Sleep: What the Trials Actually Measured, or browse the Stress & Sleep collection.
The research above describes magnesium and glycine as ingredients, not the finished MAXIS product. Anyone with kidney disease, or who is pregnant or nursing, should talk to a healthcare professional before taking magnesium.
FAQ
Is magnesium glycinate good for sleep?
One recent trial in healthy adults with poor sleep found a small benefit over placebo on a sleep-difficulty score, while reviews describe the overall evidence as mixed. It is more accurate to see magnesium as an essential nutrient worth getting enough of than as a sleep aid; the research on relaxation and normal sleep quality is promising but limited.
How long before bed should I take magnesium glycinate?
The 2025 trial used 30 to 60 minutes before bed. There is no official timing rule, so take it whenever you will do so consistently.
How long does magnesium glycinate take to work?
The trial ran for four weeks, and both groups improved within the first week on the single-item rating. Expect to judge it over weeks rather than a single night.
Can I take magnesium glycinate every night?
Daily use is common, but keep total supplemental magnesium in mind. The upper limit is 350 mg a day from supplements, so check every product you take.
References
- Schuster J, Cycelskij I, Lopresti A, Hahn A (2025). Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Nature and Science of Sleep, 17, 2027–2040. doi.org/10.2147/NSS.S524348
- Arab A, Rafie N, Amani R, Shirani F (2023). The role of magnesium in sleep health: a systematic review of available literature. Biological Trace Element Research, 201(1), 121–128. abstract via fabresearch.org
- Yamadera W, Inagawa K, Chiba S, et al. (2007). Glycine ingestion improves subjective sleep quality in human volunteers, correlating with polysomnographic changes. Sleep and Biological Rhythms, 5, 126–131. link.springer.com
- NIH Office of Dietary Supplements. Magnesium: Fact Sheet for Health Professionals. ods.od.nih.gov
†These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
This article is for information only and isn’t medical advice. Talk to your doctor before starting a supplement, especially if you take medication or have a health condition.
Written by
MAXIS Team
