Magnesium and sleep: Can this mineral improve the quality of sleep?

Can magnesium help you sleep?

Magnesium can help the body wind down more easily in the evening in several ways. This mineral supports the normal functioning of nerves and muscles and is involved in processes that facilitate the transition from activity to relaxation.

The neurotransmitter GABA plays an important role in this. It has a calming effect in the brain and helps to reduce excessive activity. Magnesium supports these calming processes and can therefore help the body prepare for sleep more effectively.

The sleep hormone melatonin is also linked to magnesium. Melatonin regulates the sleep-wake cycle and signals to the body that it is time to feel tired. Magnesium is involved in processes that are important for the production and regulation of this hormone.

Added to this is its effect on the muscles. A severe magnesium deficiency can lead to muscle cramps, twitching or restlessness. Such symptoms can make it difficult to fall asleep or disrupt sleep.

All this explains why magnesium repeatedly plays a role when it comes to sleep. However, this does not answer the question of whether taking extra magnesium actually leads to better sleep. To find out, it is worth taking a look at the studies.

What do the studies say?

The body of research on magnesium and sleep is still relatively limited, but it does reveal some interesting findings. The most frequently investigated factors were the time taken to fall asleep, subjective sleep quality and symptoms of insomnia.

A systematic review with a meta-analysis from 2021 summarised three randomised, controlled trials involving a total of 151 older adults with sleep problems. The most striking finding: participants who took magnesium fell asleep on average around 17 minutes faster than those in the control groups.

However, the difference in total sleep duration was not clear-cut. Furthermore, the underlying studies were small and, in some cases, prone to bias. The validity of the findings is therefore limited.

More recent research findings also provide evidence of a possible positive effect. In a study from 2025, 155 adults with poor sleep quality were given either 250 milligrams of elemental magnesium in the form of magnesium bisglycinate or a placebo containing no magnesium for four weeks.

Sleep improved in both groups. However, the magnesium group fared slightly better. The additional effect was small but measurable. It was also interesting to note that people with a previously rather low magnesium intake might benefit more.

Magnesium L-threonate has also been investigated in the meantime. In a small study from 2024, some subjectively perceived and objectively measured sleep parameters improved. However, with 80 participants and a study duration of just three weeks, the study is too small to draw a clear recommendation from it.

The overall picture is therefore not clear-cut: magnesium could, however, improve falling asleep and certain aspects of sleep quality in particular. However, further research is needed to determine exactly how great the benefits are in everyday life and which people benefit most from it.

Which form of magnesium is recommended for better sleep?

Anyone looking for magnesium to improve their sleep will quickly come across various forms. Two of these are mentioned particularly frequently: magnesium glycinate or magnesium bisglycinate, and magnesium L-threonate.

Magnesium bisglycinate is bound to the amino acid glycine. Glycine itself is also being investigated for its potential effects on sleep and recovery. This form is well absorbed by the body and is generally well tolerated. Furthermore, it was specifically examined for its potential benefits in relation to sleep problems in a recent study involving 155 adults.

Magnesium L-threonate is considered well tolerated and has been researched primarily in relation to brain function and nerve cells. This form was developed to ensure that magnesium is particularly well absorbed into the central nervous system. Initial small-scale studies are also yielding interesting results regarding sleep. However, the findings are not consistent: whilst individual subjective and objective sleep parameters improved in one study, a more recent investigation showed no clear advantage over placebo in terms of objective sleep measurements. 

Magnesium citrate and magnesium oxide are less recommended. Although magnesium citrate is well absorbed, it can have a laxative effect and cause abdominal discomfort or diarrhoea. Magnesium oxide is absorbed less efficiently than some other compounds and is frequently used in higher doses as a laxative.

It is not currently possible to say definitively which form of magnesium is best suited for sleep. Magnesium bisglycinate is an obvious option due to its good tolerability and the existing clinical study. However, there is as yet no evidence to suggest that it is actually more suitable for sleep than other forms of magnesium.

How much magnesium is advisable?

More magnesium is not automatically better. How much is advisable also depends on how much is already being obtained through the diet. For adults, 300 milligrams per day for women and 350 milligrams per day for men are considered estimates for an adequate total intake. This already includes magnesium from food and drink.

Anyone wishing to try magnesium for sleep problems should therefore not simply take the entire daily amount as a dietary supplement. There is as yet no scientifically established dose for better sleep.

In the recent study on magnesium bisglycinate, for example, 250 milligrams of elemental magnesium was used daily. However, this is a study dose and not a general dosage recommendation. The Federal Institute for Risk Assessment (BfR) recommends a maximum daily intake of 250 milligrams of magnesium from dietary supplements. Higher amounts can cause diarrhoea and other gastrointestinal complaints in particular. The BfR also recommends spreading the daily intake over at least two doses.

What side effects and interactions are possible?

Magnesium from food is generally not a problem for healthy people. The situation may be different with dietary supplements: higher amounts can cause diarrhoea, abdominal cramps and nausea. Some magnesium compounds have a stronger laxative effect than others.

Particular caution is advised in cases of impaired kidney function. Normally, the kidneys excrete excess magnesium. If they are not functioning properly, the mineral can accumulate in the body. Very high magnesium concentrations can cause, amongst other things, muscle weakness, low blood pressure and cardiac arrhythmias.

Interactions with medicines are also possible. For example, magnesium can impair the absorption of certain antibiotics and of bisphosphonates used to treat osteoporosis. It may therefore be necessary to leave a gap between doses. Anyone who takes medication regularly or suffers from kidney disease should therefore discuss magnesium supplements with their doctor or pharmacist beforehand.

Which foods are rich in magnesium?

Magnesium is found in many plant-based foods. Particularly good sources include nuts and seeds, wholegrains, pulses and green vegetables.

For example, the following are rich in magnesium:

• Pumpkin seeds, sunflower seeds and almonds
• Oatflakes and other wholegrain products
• Lentils, beans and chickpeas
• Spinach and Swiss chard
• Cocoa
• some magnesium-rich mineral waters

If you eat a varied diet and regularly include wholegrains, pulses, nuts and vegetables in your meals, you can usually meet your magnesium requirements through your diet alone. Dietary supplements are therefore not strictly necessary.