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Magnesium for sleep has modest, low-quality evidence behind it. A 2021 review of three small trials in older adults found people fell asleep about 17 minutes faster with magnesium than with placebo, but the authors rated the evidence low to very low quality. A 2025 trial of magnesium bisglycinate in adults with poor sleep found a small benefit on one insomnia scale and no difference on others. Magnesium may help some people, especially those who get little from food, but it is not a proven sleep aid. For long-lasting insomnia, sleep specialists recommend cognitive behavioral therapy for insomnia (CBT-I) first.
Peptide Labs sells some of the products described below. This article is general information, not medical advice.
Key Takeaways
- Trials of magnesium for sleep are few, small and short, and most relied on questionnaires.
- Older adults in three trials fell asleep about 17 minutes sooner, on low-quality evidence.
- A 2025 bisglycinate trial found a small effect on insomnia scores and none on other sleep scales.
- Magnesium glycinate also supplies glycine, which has its own small, industry-linked sleep studies.
- Keep magnesium from supplements within 350 mg a day unless a clinician advises otherwise.
Does magnesium help you sleep? The short answer
Maybe a little, for some people. Magnesium takes part in hundreds of enzyme reactions, including nerve and muscle function, and researchers have proposed that it calms nerve signaling by acting on NMDA and GABA receptors. A 2023 systematic review of nine studies with 7,582 adults found that observational studies link better magnesium status with better sleep, while randomized trials gave contradictory results. An association does not show that taking magnesium improves sleep. ODS reports that 48% of Americans get less magnesium from food than the average requirement, so any benefit may depend on how much you already eat.
What the clinical trials found
| Study | Who and how long | Form | Main result |
|---|---|---|---|
| Abbasi 2012 | 46 older adults in Iran, 8 weeks | Form not given in the abstract | Better insomnia scores and sleep efficiency; total sleep time no different |
| Mah and Pitre 2021 review | 3 trials, 151 older adults | Various | Fell asleep 17 minutes sooner; low to very low quality evidence |
| Hausenblas 2024 | 80 adults aged 35 to 55, 21 days | L-threonate (Magtein) | Better insomnia and ring-measured sleep scores; funded by the maker |
| Schuster 2025 | 155 adults aged 18 to 65, 4 weeks | Bisglycinate | Small drop in insomnia score; no change on other scales |
Older adults with insomnia
The most cited trial, from Tehran in 2012, gave 46 older adults with insomnia magnesium or placebo for 8 weeks. The magnesium group reported better insomnia severity scores, sleep efficiency and time to fall asleep, and had higher blood melatonin and lower cortisol, but total sleep time did not differ. A 2021 meta-analysis by Mah and Pitre pooled this and two other trials (151 older adults in total). Sleep onset came 17.36 minutes sooner with magnesium, and total sleep time rose by about 16 minutes, which was not statistically significant. All three trials had moderate to high risk of bias, and the authors called the literature substandard for firm recommendations.
The 2025 magnesium bisglycinate trial
In a randomized, placebo-controlled trial published in Nature and Science of Sleep, 155 adults in Germany who reported poor sleep took magnesium bisglycinate or placebo for 4 weeks. Insomnia Severity Index scores fell 3.9 points with magnesium and 2.3 points with placebo, a difference the authors called modest (effect size 0.2). There was no significant difference on other sleep, sleepiness, fatigue, stress or mood scales. People who ate less magnesium seemed to respond more, but that was an exploratory finding. The study was academically funded, used self-reported outcomes only, and lasted a month.
Magnesium L-threonate
A 2024 trial gave 80 adults with self-reported sleep problems magnesium L-threonate (Magtein) or placebo for 21 days. Both groups improved on the Insomnia Severity Index, with the magnesium group ahead by weeks 2 and 3, and an Oura ring showed better deep and REM sleep scores. The study was funded by the company that makes the ingredient, which also supplied it and co-authored the paper.
Magnesium glycinate for sleep: the magnesium or the glycine?
Magnesium glycinate is popular for sleep because it pairs magnesium with glycine, an amino acid. Small Japanese studies found that 3 grams of glycine before bed improved subjective sleep quality and, in one, shortened the time to fall asleep measured in a sleep lab. Researchers from Ajinomoto, an amino acid company, ran or co-authored that work, and the studies were small. In the 2025 bisglycinate trial, each serving also delivered about 1.5 grams of glycine, so the results cannot separate the two ingredients. We did not find a trial that compares glycinate with citrate or other forms for sleep. For how the forms differ in absorption and laxative effect, see magnesium glycinate vs citrate.
Sleep habits and CBT-I come first
The American Academy of Sleep Medicine’s 2021 guideline makes one strong recommendation for chronic insomnia in adults: cognitive behavioral therapy for insomnia, which combines education about sleep with techniques such as stimulus control and sleep restriction. The guideline also says sleep hygiene tips alone are not an effective stand-alone therapy, though they remain part of CBT-I. Talk with a clinician if poor sleep lasts for weeks, affects your days, or comes with loud snoring, pauses in breathing, or an urge to move your legs at night.
Safety before trying magnesium for sleep
- Upper limit: ODS sets 350 mg a day for magnesium from supplements and medicines in adults; food does not count toward it.
- Stomach effects: higher amounts often cause diarrhea, nausea and cramps; oxide, chloride, carbonate and gluconate are the forms most often reported. Our magnesium oxide guide explains why.
- Kidneys: the risk of magnesium building up rises with kidney disease; ask a clinician first.
- Medicines: separate magnesium from bisphosphonates by 2 hours and from tetracycline or quinolone antibiotics as ODS advises, and ask a pharmacist about levothyroxine.
- Combination sleep products: check every ingredient, not just the magnesium.
Sleep products that contain magnesium
Many nighttime formulas add magnesium to other ingredients, which makes it impossible to tell what any one ingredient does. InnoSupps Night Shred lists 200 mg of magnesium as magnesium oxide per two capsules, along with 3 mg of melatonin, KSM-66 ashwagandha, GABA, chamomile, valerian, passion flower, 5-HTP, L-tryptophan, CLA and L-carnitine. The label says it is not for pregnant or breastfeeding women, not to use it with alcohol or before driving, and to stop two weeks before surgery. Ashwagandha has had liver injury reports, covered in our cortisol belly guide, and 5-HTP can interact with antidepressants; see our 5-HTP guide. Melatonin is a hormone with its own evidence and cautions.
cbdMD Broad Spectrum CBD PM Softgels list magnesium glycinate inside a 250 mg proprietary blend, so the magnesium amount is not stated, together with 50 mg of CBD, 10 mg of CBN and 3 mg of melatonin per softgel. The label warns that it may cause drowsiness and should not be combined with alcohol or medication.
Frequently Asked Questions
Does magnesium help you sleep?
Small trials suggest a modest effect for some people, mainly on how fast they fall asleep. The evidence is low quality, and results differ between studies.
Is magnesium glycinate good for sleep?
One 2025 trial found a small improvement in insomnia scores with magnesium bisglycinate. It also contains glycine, so the effect of magnesium alone is unclear.
How long does magnesium take to work for sleep?
Trials lasted 3 to 8 weeks and measured changes over that time. There is no good evidence for an immediate effect.
Which form of magnesium was used in sleep studies?
Recent trials used bisglycinate and L-threonate; older trials used various forms. No study has compared forms head to head for sleep.
Can I take magnesium with melatonin?
Some products combine them. Melatonin has its own cautions, so ask a pharmacist, especially if you take other medicines.
Is it safe to take magnesium every night?
For healthy adults, staying within the label and the 350 mg upper limit for supplements is the general safety guidance. People with kidney disease should ask a clinician first.
Questions about a label? Contact us or read our Buyer’s Guide. Follow the label and ask a healthcare provider before starting any supplement, especially if you take medicines. 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.
Last reviewed September 2026.
Related guides: Magnesium Glycinate vs Citrate: How the Types of Magnesium Compare, Magnesium Oxide: Elemental Magnesium, Absorption, Laxative Effect and Safety, Cortisol Belly: Stress, Belly Fat and What Cortisol Supplements Show, Ashwagandha Benefits, Side Effects and Safety: What Studies Show, Melatonin Side Effects: Interactions, Alcohol, Gummies and Long-Term Use, L-Theanine Benefits, Side Effects and the Caffeine Combination, Best Time to Take Magnesium: Morning or Night and Medicine Timing, Magnesium and Alcohol: Does Drinking Deplete Magnesium?, Valerian Root: Benefits, Sleep Research, Side Effects and Interactions, Glycine Benefits: Sleep Research, Supplements and Side Effects.