In short: Studies on magnesium for sleep show that older adults fell asleep just over 17 minutes faster on average. In a controlled study with 155 adults, sleep problems improved more with magnesium bisglycinate than with a dummy pill. If you want to try it, take 250 mg of magnesium in the evening with food, for example as bisglycinate, and stick with it for about four weeks.
The key points
- Falling asleep faster: In a pooled analysis of three studies in older adults, participants taking magnesium fell asleep just over 17 minutes faster on average.
- Bisglycinate has its own study: In 155 adults with poor sleep, sleep problems improved more with 250 mg of magnesium bisglycinate than with placebo, most clearly in those with low dietary magnesium.
- Glycine as a bonus: Bisglycinate is bound to the amino acid glycine. Glycine alone, taken before bed, improved perceived sleep quality in studies.
- How to take it: 250 mg of magnesium a day, in the evening with food. This is also the upper limit for magnesium supplements in the EU.
- Melatonin with magnesium: Melatonin has an authorised claim for helping you fall asleep. In studies combining it with magnesium, participants slept better than with placebo.
Contents
- Does magnesium help you fall asleep?
- Why is magnesium linked to sleep?
- Which magnesium is best for sleep?
- How much magnesium for sleep?
- Melatonin with magnesium: what does the combination do?
- Magnesium and sleep problems: what you should know
- How to try it sensibly
- Frequently asked questions
- Limits of the research and all sources
Does magnesium help you fall asleep?
In several studies, yes: with magnesium, participants fell asleep faster, and sleep problems improved more than with a dummy pill. The strongest case is for people who sleep poorly, older adults, and anyone getting little magnesium from food. It was usually taken daily over several weeks.
What studies show: Researchers pooled three studies with 151 older adults. Those taking magnesium fell asleep just over 17 minutes faster on average than with a dummy pill.1 In one of them, 46 older adults took 500 mg of magnesium for eight weeks. Several measures improved, including sleep duration and time to fall asleep.2
One of the largest individual studies comes from Germany. 155 adults with poor sleep took 250 mg of magnesium as bisglycinate or a dummy pill for four weeks. Sleep problems improved more with magnesium. The benefit was clearest in people who got little magnesium from their diet.5
Our take: Magnesium is worth trying if you struggle to fall asleep, especially if you get little magnesium from food. The best-evidenced form is bisglycinate at 250 mg in the evening over four weeks. Take it regularly and give it time — in the studies, the difference showed up after several weeks. Exactly how much it helps, and for whom, is something larger studies still need to show.
Why is magnesium linked to sleep?
Because magnesium plays a role in the nervous system, and because in observational studies, people who get more magnesium from their diet are less likely to sleep too little. Together, that makes the idea easy to follow.
There is no officially authorised claim specifically about magnesium and sleep. Among the claims that are officially confirmed are these two:
- Magnesium contributes to normal functioning of the nervous system.
- Magnesium contributes to normal psychological function.
What studies show: In a long-running US study with almost 4,000 adults, people with the highest magnesium intake slept fewer than seven hours less often than those with the lowest intake.10 An analysis of around 21,800 US adults found a similar link for magnesium from food.11 Laboratory findings show that magnesium dampens the excitability of nerve cells and is involved in the body's internal clock.22
Which magnesium is best for sleep?
Right now, magnesium bisglycinate has the strongest case. This form was used in a large, recent controlled sleep study, and it comes with a second building block: the amino acid glycine, which has itself been studied for sleep.
| Form | Study | Effect on sleep |
|---|---|---|
| Bisglycinate | 155 adults, 250 mg, 4 weeks5 | Sleep problems improved more than with placebo |
| Glycine (building block in bisglycinate) | Adults with poor sleep, 3 g before bed13, 14 | Better perceived sleep quality, faster into deep sleep |
| Oxide | 46 older adults, 500 mg, 8 weeks2 | Several measures better than placebo |
| L-threonate | 80 adults, 21 days8 | Some sleep and daytime measures better |
| L-threonate | 100 adults, 6 weeks9 | One questionnaire score better |
What studies show: In studies of people who slept poorly, 3 g of glycine before bed improved perceived sleep quality. In one, participants reached deep sleep faster; in the other, they felt fresher in the morning.13, 14 You can read more about this form in our article on magnesium glycinate. We also have a dedicated article on L-threonate.
Our take: For the evening, we recommend bisglycinate. It has the best sleep study behind it, and the bound glycine fits the topic well. Oxide also showed benefits in a study with older adults, so the form isn't everything. More important than the perfect form is that you tolerate your magnesium well and take it regularly. We explain which forms are well absorbed under Which magnesium is best?
How much magnesium for sleep?
With 250 mg of magnesium a day, you match exactly the amount used in the bisglycinate study.5 Overall, the studies mostly used 250 to 500 mg a day. For food supplements, the European Food Safety Authority (EFSA) recommends not exceeding 250 mg a day, because higher amounts more often cause digestive upset.20
So you don't need an especially high amount for sleep. The usual 250 mg is enough, and more is more likely to lead to loose stools. You can read what happens with too much magnesium under Too much magnesium.
What studies show: 250 mg as bisglycinate showed a benefit over placebo in the German study.5 In the study with older adults, it was 500 mg a day, split into two doses.2
Melatonin with magnesium: what does the combination do?
Melatonin is a hormone your body makes itself in the evening. Unlike magnesium, melatonin has an authorised EU claim about falling asleep. It reads: "Melatonin contributes to the reduction of time taken to fall asleep." It may only be used for products with 1 mg of melatonin per serving, taken shortly before bedtime.18 According to the German consumer body Verbraucherzentrale, this typically shortens the time to fall asleep by around 10 to 20 minutes.18 Prescription-only melatonin medicines contain 2 mg.18
What studies show: In an Italian care home, 43 older residents slept markedly better with a mix of 5 mg melatonin, 225 mg magnesium and zinc than with placebo.15 A study with 35 adults tested 1.9 mg melatonin with 200 mg magnesium in coffee capsules. Here too, participants slept better than with placebo.17 In a study with 84 women with PCOS, four groups received either melatonin, magnesium, both, or two dummy pills. Sleep quality improved in the two groups that received melatonin, with or without magnesium.16
Important: Melatonin is a hormone, not a harmless extra. The Verbraucherzentrale advises against giving it to children without medical guidance and urges caution for pregnant and breastfeeding women. You shouldn't drive after taking it.18 If you take other medicines, check with your pharmacist or GP first.
The two work in different ways. Melatonin signals "night" to the body. Magnesium contributes to normal functioning of the nervous system. If you want to specifically shorten the time it takes to fall asleep, the option is 1 mg of melatonin shortly before bed, keeping the warnings above in mind.18 Magnesium can then simply be added to your evening meal as usual.
Magnesium and sleep problems: what you should know
If you occasionally sleep badly, magnesium is worth trying. The bisglycinate study looked at exactly this group: adults who rated their own sleep as poor.5 If poor sleep continues for weeks, get the cause checked by a doctor.
What studies show: Professional bodies recommend a specific form of behavioural therapy (cognitive behavioural therapy for insomnia) as the first-line treatment for persistent insomnia. In a large comparative analysis, none of the alternatives studied, including melatonin, had better evidence than this therapy.21
Important: Get medical advice if you sleep badly for weeks, feel very tired during the day, snore heavily or have breathing pauses at night, or if restless legs keep you awake. These symptoms sometimes have treatable causes. If you have reduced kidney function, only take magnesium after checking with a doctor, as it can then build up in the body.23
How to try it sensibly
Take magnesium the way it was taken in the studies: daily, at a normal dose, over a few weeks. If you jot down a quick note on how you're sleeping along the way, you'll see clearly at the end whether it's making a difference.
How to do it in practice:
- Form: for example bisglycinate, the form used in the study with 155 adults.5
- Amount: up to 250 mg of magnesium a day from supplements.
- Timing: with your evening meal. That's a good fixed point to remember it by, though for absorption the time of day is secondary. Details are under When should you take magnesium?
- Duration: about four weeks, the same length as the bisglycinate study.5
- Track it: for a week beforehand and every morning of week four, note how long it took you to fall asleep and how rested you feel.
- Review it: if you feel better, there's nothing wrong with continuing. If nothing changed, you can just stop.
Frequently asked questions
Does magnesium make you tired or keep you awake? Magnesium doesn't work instantly. In the sleep studies, differences were measured after several weeks of regular use. For daytime tiredness, it's officially confirmed: Magnesium contributes to a reduction of tiredness and fatigue.
Can too much magnesium cause sleep problems? We haven't found a study on this. In a Swiss observational study, people who took magnesium actually tended to sleep slightly worse.12 This is probably because more people with poor sleep reach for magnesium in the first place. The typical result of too much magnesium is loose stools.20
Does magnesium help with night-time leg cramps that disturb sleep? The studies contradict each other. More on this is in our article When should you take magnesium?
What is the best magnesium for sleep? Bisglycinate has the strongest case: it has its own controlled study,5 and its bound glycine has itself been studied for sleep.13 There is no direct head-to-head comparison of the forms yet.
How soon will I notice a difference? The magnesium studies ran three to ten weeks, with differences mostly measured at the end. Plan for at least four weeks of regular use.
Can I take magnesium and melatonin together? In studies, both were given together.15, 16 Melatonin has its own precautions, see above.18 If you take other medicines, check with your pharmacist first.
Limits of the research and all sources
Most studies on magnesium and sleep are small, short, and rely on questionnaires rather than sleep-lab measurements. The quality of the studies in older adults was rated as low.1 Participants, forms and amounts vary widely, and direct comparisons of forms and studies on the best amount are missing. Whether the glycine in bisglycinate itself contributes to sleep hasn't been specifically studied. The threonate studies were funded by manufacturers, and in the second one a sleep ring showed no difference.8, 9
What stands out is how much sleep improved with the dummy pill too, in almost every study. In the study with 155 adults, sleep problems improved in both groups, and magnesium's advantage was small.5 In 100 people over 51, sleep quality improved equally with 320 mg magnesium citrate and with placebo.6 In 64 women with PCOS, 250 mg oxide showed no difference.7 Two systematic reviews reach a mixed picture: observational studies see a link, controlled studies contradict each other.3 The most recent analysis, from 2026 and covering 12 controlled studies, found inconsistent results with low to very low certainty of evidence. The authors don't consider magnesium a routine solution for insomnia, but don't rule out small benefits for perceived sleep either.4 In observational data, sleep was linked to magnesium from food, not from supplements.11 A Swiss long-term observational study of around 3,900 people found no clear link, including when measured in a sleep lab.12 The mechanisms come mainly from laboratory findings.22
For the melatonin combinations, it's usually impossible to say which ingredient is doing the work. In the four-group study, the researchers report no improvement for magnesium alone.16 The care-home study used 5 mg of melatonin, several times the amount found in food supplements.15 In the coffee-capsule study, sleep remained poor on average despite the improvement.17 An analysis of 24 studies found no clear improvement from melatonin in adults with chronic insomnia and no other conditions.19 No study so far has shown that magnesium boosts the effect of melatonin.
▸ Show all 23 studies and sources
| # | Study | Who was studied | Result | Strength of evidence |
|---|---|---|---|---|
| 1 | Mah & Pitre 2021, BMC Complement Med Ther | 3 studies, 151 older adults | Fell asleep 17 minutes faster, low quality | Meta-analysis |
| 2 | Abbasi et al. 2012, J Res Med Sci | 46 older adults, 500 mg as magnesium oxide, 8 weeks | Sleep duration, time to fall asleep, insomnia questionnaire all improved | Small controlled study |
| 3 | Arab et al. 2022, Biol Trace Elem Res | 9 studies, over 7,500 people | Observational studies yes, controlled studies conflicting | Systematic review |
| 4 | Lopresti et al. 2026, J Diet Suppl | 12 controlled studies | Inconsistent, low certainty, not a routine solution | Systematic review |
| 5 | Schuster et al. 2025, Nat Sci Sleep | 155 adults, 250 mg bisglycinate, 4 weeks | Sleep problems improved more than placebo (small effect) | Controlled study, University of Hannover |
| 6 | Nielsen et al. 2010, Magnes Res | 100 people over 51, 320 mg citrate, 7 weeks | Sleep quality improved equally with magnesium and placebo | Controlled study |
| 7 | Gholizadeh-Moghaddam et al. 2022, Health Sci Rep | 64 women with PCOS, 250 mg oxide, 10 weeks | No difference in sleep | Controlled study |
| 8 | Hausenblas et al. 2024, Sleep Med X | 80 adults, 1 g L-threonate, 21 days | Some sleep and daytime measures better | Controlled study, funded by the supplier |
| 9 | Lopresti & Smith 2026, Front Nutr | 100 adults, 2 g L-threonate, 6 weeks | One questionnaire score better, sleep ring showed no difference | Controlled study, funded by the manufacturer |
| 10 | Zhang et al. 2021, Sleep | 3,964 US adults | Higher magnesium intake: less often under 7 hours' sleep | Long-term observational study |
| 11 | Zhao et al. 2025, Brain Behav | 21,840 US adults | Link found with magnesium from food, not from supplements | Cross-sectional study |
| 12 | Stadie et al. 2026, Eur J Nutr | ca. 3,900, Switzerland | No clear link between intake and sleep | Long-term observational study |
| 13 | Yamadera et al. 2007, Sleep Biol Rhythms | Adults with poor sleep, 3 g glycine | Better sleep quality, faster into deep sleep | Small controlled study |
| 14 | Inagawa et al. 2006, Sleep Biol Rhythms | Adults with poor sleep, 3 g glycine | Fresher and clearer-headed in the morning | Small controlled study |
| 15 | Rondanelli et al. 2011, J Am Geriatr Soc | 43 care-home residents, 5 mg melatonin + 225 mg magnesium + zinc | Sleep quality markedly better | Small controlled study, contributions not separable |
| 16 | Alizadeh et al. 2021, Nutr Metab | 84 women with PCOS, 6 mg melatonin and/or 250 mg oxide | Sleep better in the melatonin groups | Four-arm controlled study |
| 17 | Carlos et al. 2024, Chronobiol Int | 35 adults, 1.9 mg melatonin + 200 mg magnesium | Better than placebo, sleep still poor on average | Small controlled study, some authors linked to manufacturer |
| 18 | Verbraucherzentrale 2026 | Consumer information, as of 31 Aug 2026 | Authorised melatonin claim, conditions, warnings | Regulatory and consumer information |
| 19 | Choi et al. 2022, Sleep Med Rev | 24 studies, chronic insomnia | No clear improvement from melatonin in adults | Meta-analysis |
| 20 | EFSA / SCF 2001 | Regulatory assessment | Upper limit of 250 mg/day from food supplements | Official assessment |
| 21 | Baglioni et al. 2020, J Clin Med | 40 studies, insomnia | No alternative better than behavioural therapy | Network meta-analysis |
| 22 | He et al. 2025, Nat Sci Sleep | Review | Magnesium dampens nerve cells, involved in the internal clock | Review, mainly laboratory data |
| 23 | Rosner et al. 2023, Mayo Clin Proc | Review | Build-up with reduced kidney function | Review |
Author: PRONESIUM Editorial Team · Last reviewed on 29 September 2026 · This article is not a substitute for medical advice.
