Does Magnesium Glycinate Help With Sleep? What the Research Says

Magnesium glycinate is often marketed as a supplement for better sleep, but does the evidence support this?

The answer is possibly, but the evidence is still limited. A 2025 randomised, double-blind, placebo-controlled trial found a small improvement in insomnia symptoms in adults taking magnesium bisglycinate for four weeks. However, the study was relatively small and short, so it is not enough to conclude that magnesium glycinate is an effective treatment for insomnia.

If you are otherwise well and simply want to improve your sleep quality, magnesium may be worth considering. However, if you have persistent tiredness, significant sleep problems or other symptoms, it is important to consider whether something else could be affecting your sleep.

Quick Verdict

Magnesium glycinate may support sleep in some people, but it should not be considered a proven treatment for insomnia.

The most relevant recent trial found a small improvement compared with placebo. However, only 155 people took part and the study lasted four weeks.

For someone who is otherwise well and has mild problems with sleep quality, trying magnesium for a reasonable period may be an option. However, there is no guarantee that it will help, and you should not assume that tiredness is caused by low magnesium.

If you have an underlying medical condition, take regular medication or are unsure whether magnesium is suitable for you, speak to your pharmacist or doctor before taking it.

Summary

• A 2025 clinical trial investigated 250mg of elemental magnesium from magnesium bisglycinate daily in 155 adults with poor sleep.
• The study was randomised, double-blind and placebo-controlled.
• After four weeks, the magnesium group reported a slightly greater improvement in sleep than the placebo group.
• The improvement was small, so the study does not show that magnesium will make a noticeable difference for everyone.
• The study was relatively small and lasted only four weeks.
• Previous research has also produced mixed results.
• Magnesium may be reasonable to try for mild sleep-quality problems in an otherwise healthy person, but it should not replace assessment of persistent insomnia or unexplained tiredness.
• If you have another medical condition, take regular medication or are unsure whether magnesium is appropriate for you, speak to a pharmacist or doctor.

What Does the Research Say?

The 2025 magnesium sleep study

One of the more useful recent studies was published in 2025. It was a randomised, double-blind, placebo-controlled trial involving 155 adults aged 18 to 65 who reported poor sleep.

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Magnesium Glycinate vs Bisglycinate: What’s the Difference?

In simple terms, participants were randomly assigned to receive either magnesium or a placebo. Neither the participants nor the researchers knew who was receiving magnesium during the study.

Participants took either 250mg of elemental magnesium from magnesium bisglycinate each day or a placebo for four weeks. Their sleep was assessed using questionnaires, including the Insomnia Severity Index.

What did the study find?

After four weeks, the people taking magnesium reported a slightly greater improvement in their sleep than those taking the placebo.

The difference was statistically significant, but it was small.

In practical terms, the study found some evidence of a benefit, but the improvement was not large. It would therefore be wrong to assume that everyone taking magnesium will notice a meaningful change in their sleep.

The study gives us some evidence that magnesium bisglycinate may help with sleep, but it does not prove that it will work for everyone.

How Strong Is the Evidence?

The study was useful, but there are several reasons to be cautious about drawing firm conclusions.

The study was relatively small

There were 155 participants in total.

That is enough to conduct the trial, but it is still a modest sample when trying to apply the findings to the wider population. Larger studies involving more people would give us greater confidence that the results can be reproduced.

It only lasted four weeks

This is another important limitation.

Four weeks gives us information about a possible short-term effect, but it does not tell us whether the improvement would continue if magnesium were taken for several months.

The researchers recommended longer studies in future research.

Not everyone completed the study

Of the 155 people who started the trial, 134 completed the full four weeks.

The researchers accounted for participants who did not complete the study in their main analysis, but the number of people who dropped out is still worth considering when interpreting the results.

Sleep was mainly assessed using questionnaires

The researchers mainly relied on questionnaires to assess sleep rather than objective sleep measurements.

Questionnaires are useful because they tell us how people perceive their sleep, but they do not provide the same information as objective sleep monitoring.

The researchers recommended that future studies use more objective measures of sleep as well as longer treatment periods.

Overall, I would describe this as interesting and promising evidence, but not conclusive evidence.

What Does the Wider Research Show?

The 2025 trial is not the only research looking at magnesium and sleep.

A 2023 systematic review looked at nine studies involving 7,582 adults. The observational studies suggested a possible relationship between magnesium status and sleep, but the randomised controlled trials produced conflicting results. The authors concluded that larger trials with longer follow-up were needed.

Another systematic review looked specifically at magnesium supplementation for insomnia in older adults. It found three randomised controlled trials involving 151 people. Although some measures of sleep improved, the researchers considered the overall evidence to be low to very low quality because of limitations in the available studies.

A 2024 systematic review also found some positive results, but highlighted differences between studies, including the magnesium doses and formulations used, the length of treatment and the small number of participants in many of the trials.

So, the overall evidence is not strong enough to say that magnesium glycinate treats insomnia.

When Might Magnesium Be Worth Trying?

There is a difference between wanting to improve sleep quality and having ongoing insomnia or unexplained tiredness.

For example, someone may otherwise feel well but notice that their sleep has not been as good as usual. They may feel a little more tired during the day, find themselves reaching for extra tea or coffee, having an energy drink or occasionally needing a nap.

If there are no reasons why magnesium should be avoided, trying an appropriate amount for a reasonable period and seeing whether you notice a benefit may be reasonable.

This is how I would approach it in clinical practice. I would not tell someone that they definitely need magnesium or that it will definitely improve their sleep. The evidence does not support that.

If someone wants to try it, I would give it some time rather than expecting an effect immediately. If there is no noticeable benefit after a reasonable trial, there may be little reason to continue taking it purely for sleep.

When Should You Look for Another Cause?

This is particularly important if you are regularly tired during the day.

Poor sleep is not always related to magnesium.

Iron deficiency anaemia, for example, can cause tiredness and a lack of energy. Thyroid problems can also affect energy levels and sleep.

There are also many possible causes of insomnia that have nothing to do with magnesium. These include:

• stress or anxiety
• depression
• long-term pain
• caffeine
• alcohol
• shift work
• some medicines
• menopause
• an overactive thyroid
• sleep apnoea
• poor sleep habits

Caffeine can also interfere with sleep, particularly when consumed later in the day. Tea, coffee and energy drinks can all contain significant amounts of caffeine.

Screen use may also play a role. Using smartphones and other screens immediately before bed can make it harder to settle down and get ready for sleep.

What does this mean in practice?

If you have mild sleep-quality problems but otherwise feel well, trying magnesium may be reasonable.

If you are constantly exhausted, regularly relying on several caffeinated drinks to get through the day, needing regular naps or finding that tiredness is affecting your daily life, I would not simply assume that magnesium is the answer. Speak to your doctor for advice, This is important because treating the underlying cause of poor sleep is more important than simply adding a supplement.

The same applies if you take regular medication or have another reason to be unsure whether magnesium is suitable for you. A pharmacist can also check your medicines and advise whether magnesium is appropriate.

Is Magnesium a Treatment for Insomnia?

No. The current evidence is not strong enough to describe magnesium glycinate as an established treatment for insomnia.

How Much Magnesium Should You Take For Sleep Support?

There is no established magnesium dose specifically recommended for improving sleep.

The 2025 study used 250mg of elemental magnesium per day, but this was the dose used for research purposes. It should not be interpreted as the correct dose for everyone.

The NHS states that 400mg or less of magnesium from supplements per day is unlikely to cause harm. This is a safety guideline rather than a recommended dose. Higher amounts can cause diarrhoea.

Pharmacist’s Verdict

The evidence for magnesium glycinate and sleep is promising, but still limited.

The 2025 trial was well designed and found a small improvement in sleep symptoms after four weeks of magnesium bisglycinate. However, it involved only 155 people, was relatively short and did not provide enough evidence to establish magnesium as a treatment for insomnia.

Previous research has also produced mixed results, with systematic reviews highlighting the need for larger and longer clinical trials.

For someone who is otherwise well and simply wants to improve their sleep quality, trying magnesium for a reasonable period may be worthwhile to see whether they notice a benefit. I would not expect an immediate effect, and there is no reason to keep increasing the dose if it is not helping.

However, if you are persistently tired, regularly relying on caffeine or naps, or have other symptoms, don’t automatically assume that magnesium is the answer. Anaemia, thyroid problems, depression, chronic pain, sleep apnoea, medicines and lifestyle factors can all affect sleep or daytime energy.

If you have an underlying medical condition, take regular medication or are unsure whether magnesium is suitable for you, speak to your pharmacist or doctor before taking it.

Frequently Asked Questions

Does magnesium glycinate help with sleep?

It may help some people, but the evidence is still limited. A 2025 randomised controlled trial found a small improvement in insomnia symptoms after four weeks of magnesium bisglycinate compared with placebo. More research is needed.

How much magnesium was used in the sleep study?

Participants took 250mg of elemental magnesium from magnesium bisglycinate each day for four weeks. This was the dose used in the study, not a recommended dose for everyone.

How long does magnesium take to help with sleep?

There is no established timeframe. The 2025 study found a small improvement after four weeks, but it does not tell us how quickly magnesium might work for an individual or whether the effect would continue with longer-term use.

Can I take magnesium just to improve my sleep quality?

If you are otherwise healthy and have no reason to avoid magnesium, you may choose to try it. However, there is no guarantee that you will notice a benefit.

I’m tired all the time. Should I take magnesium?

Not necessarily. Persistent tiredness can have many causes, including poor sleep, iron deficiency anaemia, thyroid problems, depression and other health conditions. If you have been tired for several weeks or your tiredness is affecting your daily life, speak to your GP.

Can caffeine affect my sleep?

Yes. Caffeine can make you more alert and can interfere with sleep. Tea, coffee and energy drinks can all contain caffeine. If you are having problems sleeping, reducing caffeine and avoiding it close to bedtime may help.

Can screen time affect sleep?

Yes. Using smartphones and other screens immediately before bed can make it harder to settle down to sleep. Reducing screen use before bedtime may help improve your sleep routine.

Can depression or anxiety affect sleep?

Yes. Stress, anxiety and depression can all contribute to sleep problems. If you think your mental health may be affecting your sleep, speak to your GP rather than relying on a supplement alone.

Can an underlying health condition affect my sleep?

Yes. Conditions such as an overactive thyroid, iron deficiency anaemia, long-term pain and sleep apnoea can affect sleep or daytime energy. If you have an underlying condition or symptoms suggesting another health problem, speak to your doctor.

Is magnesium safe for everyone?

No supplement is suitable for everyone. If you have an underlying medical condition, take regular medication, have reduced kidney function or are unsure whether magnesium is suitable for you, speak to your pharmacist or doctor before taking it.

References

1. Schuster J, Cycelskij I, Lopresti A, Hahn A. Magnesium Bisglycinate Supplementation in Healthy Adults Reporting Poor Sleep: A Randomized, Placebo-Controlled Trial. Nature and Science of Sleep. 2025;17:2027–2040.
   Randomised, double-blind, placebo-controlled trial investigating magnesium bisglycinate in 155 adults reporting poor sleep.
   PubMed – Magnesium Bisglycinate and Sleep Study
2. Arab A, Rafie N, Amani R, Shirani F. The Role of Magnesium in Sleep Health: A Systematic Review of Available Literature. Biological Trace Element Research. 2023;201:121–128.
   Systematic review examining the evidence on magnesium and sleep.
   PubMed – Magnesium and Sleep Systematic Review
3. Mah J, Pitre T. Oral magnesium supplementation for insomnia in older adults: A systematic review and meta-analysis. BMC Complementary Medicine and Therapies. 2021;21:125.
   Systematic review of randomised trials investigating magnesium supplementation for insomnia.
   PubMed – Magnesium and Insomnia Meta-analysis
4. Rawji A, et al. Examining the Effects of Supplemental Magnesium on Self-Reported Anxiety and Sleep Quality: A Systematic Review. Cureus. 2024;16:e59317.
   Systematic review examining magnesium supplementation and sleep quality.
   PubMed – Magnesium, Sleep and Anxiety Systematic Review
5. NHS – Vitamins and minerals: Magnesium
   Information on magnesium requirements and the safety of magnesium supplements.
   NHS – Magnesium
6. NHS – Insomnia
   Information on the symptoms, causes and treatment of insomnia.
   NHS – Insomnia
7. NHS – Tiredness and fatigue
   Information on common causes of persistent tiredness, including sleep problems, anaemia and thyroid conditions.
   NHS – Tiredness and fatigue

Medical Review

Clinically reviewed by Sohaib Ahmed (MPharm)
GPhC-Registered Clinical Pharmacist & Independent Prescriber

This article is for general educational purposes and is not a substitute for individual medical advice. If you have an underlying medical condition, take prescription medication, have persistent or unexplained tiredness, or are unsure whether magnesium is suitable for you, speak to your GP or pharmacist.