Do magnesium supplements help you sleep better?

Magnesium has been heavily touted as a remedy for better sleep, and there are lots of sites out there that promote it.

But what is it?

And does it actually improve your sleep?

What is magnesium?

Magnesium is a mineral that has a role in strengthening bones, helps nerve and muscle function and helps control blood-glucose levels, amongst other things. You get it naturally from your diet.

Great. So how does magnesium help sleep?

This is still debated and being investigated by researchers. Some think it may help calm down brain cell activity and it acts on the benzodiazepine receptor (think Valium or Xanax). It is thought that magnesium impacts your melatonin levels, a hormone that plays a role in regulating our sleep/wake cycle (but more of that later)

Magnesium may also promote better sleep by encouraging relaxation and reducing cortisol levels. This unfairly-maligned hormone, often called the ‘stress hormone’ (in reality is has MANY functions) is produced to help you stay on high alert and so reducing it can make it easier to get to sleep. A 2017 review of 18 studies found that magnesium did help reduce subjective anxiety (which may in turn also positively impact your sleep as anxiety and stress play a role in it). However, the review noted the poor quality of the studies and whilst a 2020 review found magnesium may have a positive impact on depressive symptoms (2 studies of which were a magnesium/anti-depressant combination) it found no significant connection to general anxiety in 2 solely magnesium studies.

Cool, so I can take it for better sleep?

Woah, slow down a little.

Firstly – let’s think about what type of magnesium we are talking about - not all magnesium is created equally. Magnesium is bound to other compounds (called chelation) so our bodies can more readily absorb it.

There are multiple forms of magnesium which have different impacts on us.

So let’s take the most hyped forms for sleep – magnesium citrate, magnesium glycinate and magnesium L-threonate.

Magnesium citrate

This is a form which is a primary ingredient in laxatives, and is even used to clean poo from your intestines before tests or surgery. So, it is primarily used in laxatives which, of course may help you sleep if night-time constipation is a problem!

Magnesium glycinate

This form is also used to treat upset stomachs, and indigestion. It may also helps regulate bodily functions such as muscle nerve function and blood pressure.

Magnesium L-threonate

This is a novel magnesium compound (magnesium bound to L-threonic acid) that is well absorbed by the body. Some brands claim it is the only form of magnesium that crosses the blood-brain barrier – and although it does that well, it just isn’t true. Other types such as citrate, chloride and taurate do this as well.

Other research shows it may help support brain health, relieve pain, prevent balding (apparently!) and – you guessed it – help with stomach issues like constipation!

Fab, so which of those is best for sleep, let’s get on it!

Frankly, this is a difficult question to answer.

Well quoted studies that support magnesium for sleep refer to administering magnesium chloride, magnesium oxide or the generic term magnesium. Specific references to citrate, glycinate and L-threonate are……..rare. If at all. The advocacy of these forms of magnesium seem to relate to their better bio-availability (i.e. how readily we absorb them). Magnesium L-theronate is a supplement endorsed by many including Andrew Huberman who advocates it as part of his ‘sleep cocktail’. L-threonate is said to promote relaxation and improve cognitive function in some animals, but it lacks research in humans. The research on supplementing with this specific form for sleep is, well, pretty much non-existent.

Others recommend glycinate and citrate. Magnesium glycinate also ‘took off’ in 2023 thanks to ‘influencers’ on Tik-tok, those well known paragons of high quality and well research health advice.

Does this matter? Maybe, maybe not. Some researchers believe it is the elemental form of magnesium itself rather than a specific compound that matters most.

But my point here is this - if experts and brands are promoting that a certain form of magnesium is best for sleep then the research should be specific and support this, or the claims come with clear caveats and disclaimers.

Okey dokey, I hear you - so does it work?

In four words – we don’t really know.

Research is….lacking. Some research suggests it may help insomnia in older adults. A 2012 study of 46 patients found elemental magnesium helped with insomnia. A 2017 study looking at the effects of magnesium chloride on depressive patients incidentally found that sleep was improved. A 2022 longitudinal study contradicted that, finding that although magnesium improved sleep duration and sleep quality it did not do so in those with depressive disorders. This study also had significant limitations including a lack of objective measures for both quality and duration, or detailed instruments (for example the study used only 1 question regarding sleep quality rather than a validated questionnaire).

Some studies have combined magnesium with other substances. A 2011 study found a combination of magnesium, melatonin and zinc appeared to improve the sleep of resident’s with primary insomnia in a long-term care facility. One 2019 study suggests that combining magnesium with melatonin and B vitamins had a beneficial effect on insomnia. Whilst it is suspected that magnesium may have an effect on melatonin levels, there is currently no real evidence to back this up or understand what the impact is.

Appeared. Beneficial effect. May. Suspected.

Counter to this, a 2023 systematic review of the literature revealed a possible association between magnesium and sleep quality whilst the RCTs (Randomised Control Trials) it reviewed revealed contradictory findings and an uncertain (their word, not mine!) association between magnesium supplementation and sleep disorders. A 2021 pooled analysis of just 3 randomised control trials on the elderly found no statistically significant association with insomnia and noted that the RCTs were poorly designed.

Possible association. Uncertain.

Still confused?

If you cherry pick studies you can provide an argument for almost anything; proper evidence is obtained when studies are repeated and the benefits reliably reproduced. You won’t be surprised if I say that far more research still needs to be done in these areas before we can really know.

But people say it works?

Well then it must be true, eh?

Anecdotal evidence is subject to multiple cognitive biases and is simply not evidence that something works. “My Dad smoked all his life and lived to 100”. “My Mum never went to the gym and lived to 95”. These are not evidence that smoking and a lack of exercise are good for you! This is why we have studies that are controlled for and consider variables that can affect study outcomes; good evidence is neutral and objective not biased and subjective.

There are many factors that contribute to good sleep and small tweaks in habits, of sleep hygiene, dealing with stress, life changes and even just mindset (to name just a few) will all help.

Who is to say that your sleep would not have improved anyway?

We just don’t know.

Ok, so, get on with it. Should I take magnesium supplements for sleep?

As always that’s for you to decide, but for me?

No.

Not specifically for sleep anyway, the evidence simply isn’t there despite what supplement companies may claim on their sites.

Putting that aside magnesium plays an important role in our physiology and so it is important you have enough. The common consensus is that you should get magnesium through your diet rather than supplementation, through foods such as dark leafy vegetables such as spinach, whole grains, beans, seeds, bananas, peanut butter, fish, beef and poultry.

Then there is the question of the quality of supplements. There are a lot of low-quality products out there, as there are with all supplements and so it is difficult to know how much magnesium you are getting. This matters, as research tells us that too much magnesium can cause some serious toilet trips and much more serious side effects such as low blood pressure, irregular heartbeat and much more. Some medications and medical conditions such as kidney disease can also lower magnesium levels.

If you think you may have a deficiency in magnesium and need to supplement, it makes sense to consult your doctor before taking supplements.

(for reference the RDA (Recommended Dietary Allowance) for magnesium is 300mg (UK) and 400-420 mg daily in the USA for men, and 270mg (UK) or 310-320mg (USA) for women)