Last updated: October 2026
Magnesium may help you sleep a little better, but the evidence is modest. In small trials, mostly in older adults or people who slept poorly, it helped people fall asleep about 17 minutes faster and rate their sleep slightly better, with the biggest gains in those low in magnesium. It is a gentle support, not a sedative.
Glycinate (also sold as bisglycinate) is the best-tolerated form for sleep. The main trials used 250 to 500mg of magnesium a day, and most people take it 30 to 60 minutes before bed. The NHS says adults need 300mg (men) or 270mg (women) a day, and that 400mg or less a day from supplements is unlikely to cause harm.
That is the short answer. Below is the longer, honest one: what the research actually found, which type to buy, how to read the label, when to take it, and who should check with a pharmacist first.
Does magnesium help you sleep?
For some people, yes, but the effect is modest rather than dramatic. Magnesium is not a sedative. It will not knock you out the way a sleeping pill does. What the better studies show is a small improvement in how easily people fall asleep and how they rate their sleep, with the biggest gains in people who were low in magnesium to begin with.
The research splits into two kinds. Studies that simply look at what people eat find that those with more magnesium in their diet tend to report better, longer sleep. Trials that actually give people magnesium or a placebo show smaller, less consistent effects. Put together, that points to magnesium mattering most when you are short of it.
Our honest take: magnesium is worth trying if your diet is patchy, you feel tense at night or you have restless, crampy legs. If you have long-term insomnia, the NHS recommends looking at sleep habits first and speaking to your GP, and magnesium works best as part of that routine rather than instead of it. Our guide to insomnia covers what a GP can offer, including CBT for insomnia.
If you snore loudly, make gasping or choking noises in your sleep, or always feel very tired during the day, see your GP rather than reaching for a supplement. The NHS lists these as signs of sleep apnoea, which needs proper testing.
Magnesium and sleep: the evidence at a glance
These are the human studies that matter most, newest first. We checked each one against its published abstract, and the limits column is as important as the results.
| Study | Who and how many | What they took | What they found | Limits |
|---|---|---|---|---|
| Lopresti and Smith, 2026 (randomised trial, Australia) | 100 adults aged 18 to 45 unhappy with their sleep | 2g a day of magnesium L-threonate or placebo for 6 weeks | Better scores for daytime sleep-related impairment, but no difference in sleep disturbance or in sleep measured by a wearable ring | Funded by the company behind the ingredient; mixed results |
| Schuster et al., 2025 (randomised trial, Germany) | 155 adults aged 18 to 65 who said they slept poorly | 250mg elemental magnesium as bisglycinate, or placebo, daily | Insomnia scores fell by 3.9 points with magnesium and 2.3 with placebo by week 4. Biggest gains in people eating the least magnesium | Small effect; questionnaires only, no objective sleep measure; short |
| Hausenblas et al., 2024 (randomised trial, USA) | 80 adults aged 35 to 55 with self-reported sleep problems | 1g a day of magnesium L-threonate or placebo for 21 days | Better deep and REM sleep scores on a wearable ring, and better mood and energy on waking | Small and short; half the authors work for AIDP, a commercial ingredient company |
| Arab et al., 2023 (systematic review) | 9 studies, 7,582 adults | Diet surveys plus supplement trials | Higher magnesium status linked with better sleep in observational studies; the trials gave contradictory results | Mixed study types; authors call for bigger trials lasting over 12 weeks |
| Zhang et al., 2022 (CARDIA study, USA) | 3,964 adults followed for years | Magnesium from food and supplements, measured by diet history | People in the top quarter for magnesium intake had about a third lower odds of sleeping under 7 hours | Observational, so it cannot prove magnesium caused the difference |
| Mah and Pitre, 2021 (meta-analysis) | 3 trials, 151 older adults with insomnia | Oral magnesium or placebo | Fell asleep 17.4 minutes faster on magnesium. Total sleep time rose 16 minutes, but that was not statistically significant | Evidence rated low to very low quality; trials at moderate to high risk of bias |
| Abbasi et al., 2012 (randomised trial, Iran) | 46 older adults with insomnia | 500mg magnesium or placebo daily for 8 weeks | Better insomnia scores and sleep efficiency, faster sleep onset, lower cortisol and higher melatonin in blood tests | Very small; one centre; total sleep time results inconsistent |
What it adds up to: the best recent trial, using bisglycinate, found a real but small improvement, and the review of older adults found people fell asleep a little faster. Nobody has yet run a large, long trial with objective sleep measures, so anyone promising that magnesium will fix your sleep is going beyond the evidence. Full references are in the sources.
Are people in the UK low in magnesium?
Because magnesium seems to matter most for people who are short of it, it is worth knowing where UK diets stand. The government’s National Diet and Nutrition Survey (NDNS) recorded what people ate over four days between 2016 and 2019. From food alone:
| Group | Average intake from food | Daily need (NHS) | Below the minimum level* |
|---|---|---|---|
| Men 19 to 64 | 301mg | 300mg | 12% |
| Women 19 to 64 | 244mg | 270mg | 11% |
| Adults 65 and over | 254mg | 300mg (men), 270mg (women) | 13% |
| Men 75 and over | 248mg | 300mg | 22% |
*The Lower Reference Nutrient Intake (LRNI): 190mg a day for men and 150mg for women. It is the amount that would only be enough for the small number of people with the lowest needs, so regularly eating less than this suggests intake is likely to be too low.
In plain terms, the average UK woman eats less magnesium than the NHS figure, and about one adult in nine eats less than the minimum level. Two caveats from the survey team: four days of food records may not reflect long-term habits, and the reference values for magnesium are based on limited data. A survey can’t tell you about your own levels, but if your diet is light on nuts, seeds, beans, wholegrains and leafy greens, you may be among the people most likely to notice a difference. See signs of magnesium deficiency and foods high in magnesium.
How magnesium works at night
Magnesium is involved in more than 300 processes in the body. Three of them matter for sleep:
- Your nervous system. Magnesium helps regulate GABA, the brain’s main “slow down” messenger, and it dampens the receptors that keep the brain alert. Magnesium contributes to the normal functioning of the nervous system and to normal psychological function.
- Your muscles. Muscles need magnesium to relax after they contract. This is why low magnesium is linked with night-time cramps and twitchy legs. Magnesium contributes to normal muscle function.
- Your stress response. In the 2012 trial, people taking magnesium also had lower cortisol, the stress hormone that should be falling in the evening.
Glycinate has a small bonus. It is magnesium bound to glycine, an amino acid with its own early research into sleep, so you get both in one. Our guide to glycine for sleep looks at that research.
Which magnesium is best for sleep?
The type matters more than most labels let on. Magnesium is always bound to another compound, and that partner decides how well it is absorbed and how kind it is to your gut.
| Form | Absorption | Gentle on the gut? | Sleep research | Best for |
|---|---|---|---|---|
| Glycinate / bisglycinate | Good | Yes, very | The best studied for sleep | Evenings, sensitive stomachs |
| Citrate | Good | Can loosen stools at higher doses | Limited | General top-up, sluggish digestion |
| L-threonate | Good | Yes | Two recent small trials funded by its makers, with mixed results | Interest in focus and memory |
| Malate | Good | Yes | Little | Daytime routines |
| Oxide | Poor | Often causes loose stools | Some older trials | Cheap tablets; not ideal |
| Sprays and oils on the skin | Unclear | Not applicable | Very little | A massage ritual, not a reliable top-up. See magnesium spray |
Our pick for sleep is glycinate (bisglycinate). It is well absorbed, it rarely upsets the stomach even at an evening dose, and it is the form used in the most recent sleep trial. Threonate gets a lot of attention online. Two recent trials funded by the companies behind it reported some better sleep scores, but in the larger one, sleep measured by a wearable ring did not change, and most of its research is about memory and focus. If you are curious, our guide to magnesium L-threonate goes into it properly.
How much magnesium should you take for sleep?
What the NHS says
The NHS says adults aged 19 to 64 need 300mg of magnesium a day (men) or 270mg a day (women), and that most people can get this from a varied diet. If you take a supplement, it says 400mg or less a day from supplements is unlikely to cause any harm, and that high doses can cause diarrhoea.
Good food sources include pumpkin seeds, almonds, spinach, wholegrains, beans and dark chocolate.
Read the label for “elemental” magnesium
This is where most people get caught out. A capsule that says “500mg magnesium glycinate” does not contain 500mg of magnesium. Glycinate is only about 14% magnesium by weight, so that capsule gives you roughly 70mg of actual, elemental magnesium. Always look for the elemental figure, which is what the studies and the NHS limits refer to.
A sensible dose
- Starting out: around 100 to 150mg of elemental magnesium in the evening.
- Doses in the main sleep trials: 250mg elemental magnesium a day (the 2025 bisglycinate trial) and 500mg a day (the 2012 older adults trial). Most people do well between 150 and 400mg.
- Upper limit from supplements: 400mg a day, counting every supplement you take (some multivitamins contain magnesium too).
Our Magnesium Glycinate Sleep Complex gives 148mg of elemental magnesium per 5g serving, from bisglycinate and citrate, with glycine, L-theanine, chamomile, passionflower, hops and oat straw. It sits comfortably inside the NHS limit alongside a normal diet, and magnesium contributes to the reduction of tiredness and fatigue.
Wondering about citrate on its own? Our magnesium citrate guide covers when it makes sense and when it can be too much for your gut at bedtime.
When to take magnesium for sleep, and how long it takes
Take it 30 to 60 minutes before bed. That gives it time to absorb and turns it into a cue that the day is over. If you find it makes you feel sluggish in the morning, which is unusual, move it earlier in the evening.
If the clocks have just changed, our 5-day plan for when the clocks go back helps your whole routine catch up.
Some people notice they feel calmer on the first night or two. For sleep itself, give it at least two to four weeks of taking it every night: the trials above measured results after four to eight weeks. There is more detail in how long magnesium takes to work and the best time to take magnesium.
Your body does not store a single dose for long. Most of what you do not use is cleared by your kidneys within a day or two, which is why taking it daily matters more than taking a big dose occasionally. Our guide to how long magnesium stays in your body explains the details.
Side effects and who should check first
Magnesium is one of the gentler supplements, and glycinate is the gentlest form. The side effects people do report are:
- Loose stools or an upset stomach. Most likely with oxide or citrate, or with a big dose in one go. Lower the dose or split it.
- Feeling groggy. Uncommon. Try taking it earlier in the evening.
- Headaches or vivid dreams. Occasionally reported online, though not well studied. Lower the dose and see if it settles.
Our full guide to magnesium side effects goes into more detail.
Check with your GP or pharmacist first if you:
- have kidney disease, because your kidneys are what clear extra magnesium
- take antibiotics such as tetracyclines or quinolones, or osteoporosis medicines (bisphosphonates), as magnesium can reduce how well they are absorbed and may need to be taken a few hours apart
- take any regular prescription medicine, or are pregnant or breastfeeding
Magnesium vs melatonin and other sleep aids
In the UK, melatonin is a prescription-only medicine, mainly used short term for people over 55 and for some children under specialist care. You cannot buy it over the counter here the way you can in the US. That is a big part of why magnesium has become one of the most popular sleep supplements in the UK.
| Magnesium | Melatonin | CBD oil | |
|---|---|---|---|
| UK status | Food supplement | Prescription only | Food supplement |
| How it works | Supports the nervous system and muscles | A hormone that signals night-time | Works with the body’s endocannabinoid system |
| Feels like | Gentle, builds over weeks | Shifts your body clock | Varies from person to person |
| Can be combined? | Magnesium is commonly taken alongside CBD. Ask your prescriber before combining anything with melatonin. | ||
For a closer comparison, see CBD oil vs melatonin, or read about reishi mushroom for sleep if you prefer a warm evening drink. Herbal options people often weigh up against magnesium include valerian root and passionflower, and our round-up of natural sleep aids ranks them by evidence.
The FSA’s 10mg a day figure is precautionary advice rather than a legal limit, set while longer-term safety research continues. At Evopure we think it is a very cautious figure, and many adults use more. If you go above it, increase slowly, and check with your GP or pharmacist first if you take any medication.
Easy ways to take magnesium for sleep
The sleepy girl mocktail
The TikTok favourite is simple: tart cherry juice, a serving of magnesium powder and a splash of sparkling water, sipped about half an hour before bed. A powder works better than a tablet here because it dissolves into the drink. Our UK sleepy girl mocktail recipe has the full method.
A simple evening routine
- Caffeine cut-off: nothing caffeinated after early afternoon.
- Lights down: dim the lights and put your phone away an hour before bed.
- Your magnesium drink: 30 minutes before bed, hot or cold.
- Optional extras: some people add a few drops of Sleep CBD Oil or a mug of reishi cacao.
- Same time every night: a consistent bedtime and wake time does more than any supplement.
If you get twitchy or crampy legs at night, our guides to magnesium for restless legs and leg cramps at night are worth a read too. If you fall asleep fine but wake in the small hours, see why you wake up at 3am.
Prefer food first? See foods high in magnesium.
Magnesium for sleep in perimenopause, pregnancy and children
Perimenopause and menopause
Broken sleep is one of the most common complaints in perimenopause, and magnesium is a popular part of many women’s evening routine. Research specifically in menopausal sleep is limited, so treat it as a sensible support rather than a fix, and talk to your GP about options such as HRT if sleep is badly affected. We cover this in more depth in magnesium for menopause and perimenopause and sleep.
Pregnancy and breastfeeding
Speak to your midwife or GP before taking any supplement for sleep. We don’t recommend our products during pregnancy or breastfeeding. Our guide to magnesium in pregnancy explains what is known.
Children
Children need much less magnesium than adults, and adult sleep products are not designed for them. Talk to your GP or pharmacist first, and see are magnesium gummies safe for kids? All Evopure products are for adults (18+) only.
Magnesium for sleep and anxiety
Many people look for magnesium because worry is what keeps them awake. A 2017 review of 18 studies found the evidence suggests magnesium may help with feelings of anxiety in people prone to it, such as those with mild anxiety or premenstrual symptoms, but the quality of the studies was poor. Magnesium contributes to normal psychological function and the normal functioning of the nervous system, which is why it’s often part of an evening wind-down. If anxiety is affecting your daily life, see your GP. See magnesium for anxiety, anxiety at night and how to stop overthinking.
Magnesium for sleep and constipation
If you want help with both, magnesium citrate is the form people usually choose, because it draws water into the bowel and can loosen stools. That also means a large dose of citrate at bedtime can send you to the loo, so start low. Glycinate (bisglycinate) is gentler on the gut. Our Magnesium Glycinate Sleep Complex combines bisglycinate and citrate. See magnesium for constipation and glycinate vs citrate vs threonate.
Magnesium creams, sprays and baths for sleep
Magnesium body butters, sprays and Epsom salt baths are popular at bedtime. A 2017 review concluded that the idea of magnesium being absorbed through the skin is scientifically unsupported, so they’re unlikely to raise your magnesium levels. The ritual itself, a warm bath or a slow massage before bed, can still be a relaxing part of a wind-down routine. If you want to top up magnesium, food or an oral supplement is the proven route. See magnesium spray.
Common mistakes
- Buying oxide because it looks strong on the label. The number is high but very little is absorbed.
- Reading the compound weight, not the elemental weight. 500mg of glycinate is roughly 70mg of magnesium.
- Taking it now and then. Magnesium works best taken every evening for a few weeks.
- Doubling up without realising. Add up magnesium from every supplement, including multivitamins, and stay at 400mg or less.
- Expecting a sleeping pill. It is a gentle support, not a sedative.
Related guides
- Comparing brands? See best magnesium supplement UK: how to choose.
- Prefer a drink to a tablet? See magnesium powder: benefits, sleep and how to take it.
- Habits come first. See how to sleep better: 12 sleep hygiene habits.
- Teeth grinding: causes and how to stop.
- Magnesium glycinate: benefits, dose and timing.
- Best CBD oil for sleep: our picks and the research.
- Magnesium for kids’ sleep: what the evidence says.
- For the amino acid itself, read our guide to glycine for sleep.
- How valerian root compares for sleep.
- Epsom salt baths and sleep, including the best time to have one.
- Our 60-minute wind-down routine.
- GABA supplements: do they work for sleep?
- How much deep sleep adults need.
- Wondering how it feels? See does magnesium make you sleepy?
Buying for someone who struggles to sleep? See our sleep gifts guide.
Black Friday, 27 to 30 November: see our Black Friday magnesium and supplement deals.
FAQs
Does magnesium help you sleep?
It may help a little, especially if you don’t get enough magnesium from food. Small trials found people fell asleep about 17 minutes faster and rated their insomnia slightly better than on a placebo, but the evidence is low quality and the effects were modest. Magnesium is not a sedative, so think of it as part of a good evening routine.
Which magnesium is best for sleep?
Magnesium glycinate (bisglycinate) is our pick. It is well absorbed, gentle on the stomach and it is the form used in the most recent sleep trial, which gave 250mg of elemental magnesium a day. Citrate also absorbs well but can loosen stools. Oxide is poorly absorbed.
How much magnesium should I take for sleep?
The main trials used 250 to 500mg of magnesium a day. Most people start at around 100 to 150mg of elemental magnesium in the evening. The NHS says 400mg or less a day from supplements is unlikely to cause harm, so count every supplement you take, including multivitamins.
When should I take magnesium for sleep?
Take it 30 to 60 minutes before bed, every evening. In the trials, results were measured after four to eight weeks of daily use, so give it at least two to four weeks before judging whether it suits you.
Does magnesium help you stay asleep or just fall asleep?
The clearest finding is for falling asleep: a review of three trials in older adults found people fell asleep about 17 minutes faster. Total sleep time rose by about 16 minutes, but that result was not statistically significant, so the evidence for staying asleep is weaker.
Is magnesium better than melatonin for sleep?
They do different jobs. Melatonin is a hormone that shifts your body clock, and in the UK it is prescription only. Magnesium is a food supplement that contributes to the normal functioning of the nervous system. Ask your prescriber before combining anything with melatonin.
Does magnesium glycinate make you sleepy?
Not in the way a sleeping pill does. Most people describe feeling calmer and more relaxed, which makes it easier to drift off. If you feel groggy the next morning, take it a little earlier in the evening.
Does magnesium glycinate make you poop?
Rarely. Glycinate is the form least likely to loosen your stools. Citrate and oxide are much more likely to, especially at higher doses. If it happens, lower the dose or split it across the evening.
Can magnesium cause insomnia or vivid dreams?
A small number of people report this, although it is not well studied. If it happens to you, try a lower dose or take it earlier in the evening.
How long does magnesium glycinate stay in your system?
Most of a single dose that your body does not use is cleared by the kidneys within about a day or two. That is why taking it every evening matters more than taking a large dose occasionally.
Is magnesium glycinate the same as bisglycinate?
Effectively, yes. Bisglycinate means each magnesium is bound to two glycine molecules, which is how most glycinate supplements are made. The names are used interchangeably.
Can I take magnesium every night, and with CBD?
Yes, most healthy adults can take magnesium every night within the NHS guide of 400mg or less a day from supplements. Magnesium and CBD are often taken together in an evening routine. If you take prescription medicines, check with your pharmacist first.
Does magnesium make you sleepy?
Not in the way a sleeping pill does. Magnesium isn’t a sedative, so most people don’t feel drowsy straight after taking it. Many take it 30 to 60 minutes before bed as part of a wind-down routine. Magnesium contributes to normal psychological function and the normal functioning of the nervous system.
Can magnesium make you tired during the day?
It’s not common at usual doses. If you feel drowsy, try taking it in the evening instead. Magnesium contributes to the reduction of tiredness and fatigue.
Is magnesium good for sleep and anxiety?
A 2017 review suggested magnesium may help feelings of anxiety in people prone to it, but the studies were poor quality. Magnesium contributes to normal psychological function.
Do magnesium sprays or Epsom salt baths help you sleep?
They’re unlikely to raise your magnesium, as a 2017 review found absorption through the skin is unsupported. A warm bath can still be a relaxing bedtime ritual.
Sources
- NHS. Vitamins and minerals: magnesium.
- NHS. Insomnia.
- NHS. Melatonin.
- Schuster J et al. (2025). Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Nature and Science of Sleep.
- Abbasi B et al. (2012). The effect of magnesium supplementation on primary insomnia in elderly: a double-blind placebo-controlled clinical trial. Journal of Research in Medical Sciences.
- Mah J, Pitre T (2021). Oral magnesium supplementation for insomnia in older adults: a systematic review and meta-analysis. BMC Complementary Medicine and Therapies.
- Boyle NB et al (2017). The effects of magnesium supplementation on subjective anxiety and stress: a systematic review. Nutrients.
- Arab A et al. (2023). The role of magnesium in sleep health: a systematic review of available literature. Biological Trace Element Research.
- Zhang Y et al. (2022). Association of magnesium intake with sleep duration and sleep quality: findings from the CARDIA study. Sleep.
- Hausenblas HA et al. (2024). Magnesium-L-threonate improves sleep quality and daytime functioning in adults with self-reported sleep problems: a randomized controlled trial. Sleep Medicine: X.
- Lopresti AL, Smith SJ (2026). The effects of magnesium L-threonate (Magtein) on cognitive performance and sleep quality in adults: a randomised, double-blind, placebo-controlled trial. Frontiers in Nutrition.
- Public Health England and Food Standards Agency (2020). National Diet and Nutrition Survey: results from years 9 to 11 (2016 to 2017 and 2018 to 2019), table 5.9 (magnesium).
- NHS. Sleep apnoea.
- Gröber U et al (2017). Myth or reality: transdermal magnesium? Nutrients.
This guide is general information, not medical advice. If you have ongoing sleep problems, speak to your GP.
