In 30 seconds
- In a meta-analysis of older adults, those who took magnesium fell asleep about 17 minutes sooner than with placebo.
- In a 2025 trial with 155 adults who slept poorly, bisglycinate, which combines magnesium and glycine, improved their sleep more than placebo: 3.9 points compared with 2.3.
- EFSA sets an adequate intake of magnesium of 350 mg a day for men and 300 mg for women.
- Forms that dissolve well, such as citrate, are absorbed better than oxide.
Yes, there are studies, and they are promising. In older adults, magnesium shortened the time taken to fall asleep by about 17 minutes compared with placebo. The most recent trials, in adults who slept poorly, point in the same direction. And if you train, sleeping well is part of your recovery.
What magnesium does
It is a mineral involved in more than 300 reactions in your body and needed for your neuromuscular system to work 6. European legislation recognises these functions, among others 5:
- “Magnesium contributes to normal functioning of the nervous system”.
- “Magnesium contributes to normal muscle function”.
- “Magnesium contributes to a reduction of tiredness and fatigue”.
A varied and balanced diet and a healthy lifestyle are important.
And sleep? The authors of one of the trials describe it as a natural regulator of two brain systems involved in rest: it dampens the NMDA receptor, which excites neurons, and it supports the action of GABA, which calms them 2.
Magnesium and sleep
What the trials found
What the studies say
| Study | Who | What they took | Result |
|---|---|---|---|
| Mah and Pitre, 2021 (meta-analysis) | 3 trials, 151 older adults | 320-729 mg a day, as oxide or citrate, from 20 days to 8 weeks | They fell asleep about 17 minutes sooner than with placebo |
| Abbasi et al., 2012 | 46 older adults | 500 mg a day, 8 weeks | Better sleep efficiency and less time to fall asleep; more melatonin and less cortisol in the blood |
| Schuster et al., 2025 | 155 adults aged 18 to 65 who slept poorly | 250 mg a day as bisglycinate, 4 weeks | A 3.9-point improvement on their sleep scale, compared with 2.3 with placebo |
| Hausenblas et al., 2024 | 80 adults aged 35 to 55 | 1 g a day of magnesium L-threonate, 21 days | Better deep and REM sleep scores, and more energy during the day |
Sources: Mah and Pitre, 2021; Abbasi et al., 2012; Schuster et al., 2025; Hausenblas et al., 2024. Amounts of elemental magnesium, except for L-threonate.
In older adults
A meta-analysis brought together 3 trials with 151 older adults who slept poorly. They took between 320 and 729 mg a day, as oxide or citrate, for 20 days to 8 weeks. With magnesium, they fell asleep about 17 minutes sooner than with placebo 1.
The authors consider that larger trials are needed to refine the recommendation 1.
In the Abbasi trial, 46 older adults took 500 mg a day or placebo for 8 weeks. With magnesium, their sleep efficiency and the time taken to fall asleep improved, and melatonin rose and cortisol fell in their blood 2.
In adults who sleep poorly
This is the most recent evidence. In Germany, 155 adults aged 18 to 65 who had been sleeping poorly for more than a month took magnesium bisglycinate each night, providing 250 mg of the mineral, or placebo, between 30 and 60 minutes before bed 3.
After 4 weeks, their sleep scale improved by 3.9 points with magnesium and 2.3 with placebo. In an exploratory analysis, those who ate less magnesium improved the most. And 93% noticed no side effects at all 3.
An interesting detail: in bisglycinate, magnesium is bound to glycine, another ingredient studied for sleep. We tell you about it in glycine for sleep.
Another trial with 80 adults aged 35 to 55 tested magnesium L-threonate for 21 days. Measured with a sleep ring, their deep and REM sleep scores improved, and they reported more energy and a better mood during the day 4.
Forms of magnesium
Forms that dissolve well are absorbed better
Which form to choose
Forms of magnesium that dissolve well are absorbed better. In small studies, citrate, aspartate, lactate and chloride were absorbed better than oxide and sulphate 8.
Sleep trials have used oxide, citrate, bisglycinate and L-threonate 1 3 4.
Magnesium a day
What you need and the limit for supplements
How much you need
EFSA sets an adequate intake of 350 mg a day for men and 300 mg for women 6. Nuts, seeds, cocoa, pulses, wholegrains and vegetables are good sources 7:
| Food | Portion | Magnesium |
|---|---|---|
| Roasted pumpkin seeds | 28 g | 156 mg |
| Chia seeds | 28 g | 111 mg |
| Roasted almonds | 28 g | 80 mg |
| Cooked spinach | Half a cup | 78 mg |
| Roasted cashews | 28 g | 74 mg |
| Cooked black beans | Half a cup | 60 mg |
| Cooked brown rice | Half a cup | 42 mg |
Source: NIH, Office of Dietary Supplements. Portions converted from ounces to grams (1 ounce = 28 g).
From 40 onwards it is worth keeping an eye on it: with age, the gut absorbs less magnesium and the kidneys excrete more 8.
For magnesium from supplements, the upper limit used in Europe is 250 mg a day, not counting what comes from food. Above that, the most common effect is mild diarrhoea 7.
At what point in the evening
In the 2025 trial it was taken between 30 and 60 minutes before bed 3. That fits with the rest of your evening routine: low light, screens away and a light dinner. You will find the other habits in how to sleep better.
If you take antibiotics, bone medicines, diuretics or stomach protectors over a long period, or have kidney disease, check with your doctor 8.
If you want to see all the data on this mineral, from sleep to muscle, you will find them in magnesium: what the studies say.
Frequently asked questions
Does magnesium help you sleep?
The studies are promising. In a meta-analysis of older adults, those who took magnesium fell asleep about 17 minutes sooner than with placebo, and in a 2025 trial with adults who slept poorly, magnesium bisglycinate improved their sleep more than placebo.
Which magnesium is best for sleep?
Sleep trials have used oxide, citrate, bisglycinate and L-threonate. Forms that dissolve well, such as citrate, are absorbed better than oxide.
When should you take magnesium for sleep?
In the most recent trial it was taken between 30 and 60 minutes before bed, a window that is easy to fit into your evening routine.
How much magnesium can you take a day?
EFSA sets an adequate intake of 350 mg a day for men and 300 mg for women, counting everything you eat. For magnesium from supplements, the upper limit used in Europe is 250 mg a day.
Sources
- Mah J, Pitre T. Oral magnesium supplementation for insomnia in older adults: a systematic review and meta-analysis. BMC Complement Med Ther. 2021;21:125. View publication
- Abbasi B, Kimiagar M, Sadeghniiat K, Shirazi MM, Hedayati M, Rashidkhani B. The effect of magnesium supplementation on primary insomnia in elderly: a double-blind placebo-controlled clinical trial. J Res Med Sci. 2012;17(12):1161-1169. View publication
- Schuster J, Cycelskij I, Lopresti A, Hahn A. Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Nat Sci Sleep. 2025;17:2027-2040. View publication
- Hausenblas HA, Lynch T, Hooper S, Shrestha A, Rosendale D, Gu J. Magnesium-L-threonate improves sleep quality and daytime functioning in adults with self-reported sleep problems: a randomized controlled trial. Sleep Med X. 2024;8:100121. View publication
- Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods. View publication
- EFSA. Dietary reference values: magnesium and phosphorus. Press release from the European Food Safety Authority, 28 July 2015. View publication
- Nordic Council of Ministers. Nordic Nutrition Recommendations 2023: magnesium. Nord 2023:003. View publication
- Office of Dietary Supplements, National Institutes of Health. Magnesium: fact sheet for health professionals. View publication
Information based on published studies. It does not replace the advice of a doctor or registered dietitian. The results describe what was measured in each study, not the properties of any specific product.
