This was published 3 months ago
Magnesium spray is said to be the secret to good sleep. But does it work?
In our endless pursuit of the perfect night’s sleep, the latest popular remedy for insomnia is magnesium spray. Magnesium being used as a sleep aid is not new – oral supplements have been popular for some time, and it’s a key ingredient in TikTok’s Sleepy Girl Mocktail – but recent claims by wellness influencers and brands suggest that applying magnesium topically, rather than ingesting it, increases its effectiveness.
Despite anecdotal claims for the benefits of magnesium spray for everything from sleep to exercise recovery, how effective is it? Is applying magnesium to your skin really more effective?
Topical application of magnesium has not been shown to be more effective than consuming it.Credit: iStock
What is magnesium and how does it work?
Like calcium, sodium and potassium, magnesium is an important mineral involved in many metabolic reactions in our bodies. We cannot produce magnesium ourselves, and mostly get it from our diet – foods such as nuts, leafy greens, grains and muscle meats are all rich in it.
Professor Jerome Sarris from NICM Health Research Institute says that insofar as magnesium is “critical for a range of biochemical reactions” such as muscle and nerve function and neurological health, it can be important for sleep. But the relationship between magnesium and sleep is not direct.
Some studies have shown oral magnesium to have a modest effect on sleep, but more recent meta-analyses and reviews have concluded that more research needs to be done to confirm the relationship.
And while some adults are magnesium deficient – particularly those over 50 – overall, Sarris says most will be able to achieve ample magnesium intake from what they eat.
Dr Kristina Kendall, senior lecturer of sport and exercise at Edith Cowan University, says oral magnesium has been proven to be beneficial for muscle recovery. “There is a true benefit to supplement magnesium with athletes,” she said. “Due to the physical demands of their work, they do tend to need a higher amount of magnesium.” Those suffering from cramping or restless leg syndrome may benefit from additional magnesium.
But she says those with already ample or high levels of magnesium will see little benefit from supplementation. “The body will just excrete it.”
Oral v topical application
While those touting the benefits of the spray claim that topical application allows for greater and more rapid absorption than oral alternatives, Kendall says there is no scientific evidence for this.
She stipulates that more studies, with greater sample sizes, need to be done, but says at this stage oral supplementation has been shown to be more effective.
Kendall explains magnesium would have to travel a long way through the skin barrier to be effective. “Magnesium has to penetrate the skin and then has to either go into a hair follicle or sweat gland. And then from there, it has to get into the bloodstream. But this can be quite difficult based on the size of the magnesium molecules, but also the properties of magnesium itself.”
She adds dermal application of magnesium via a spray or cream will effectively dilute its concentration, and thus reduce its strength.
Kendall says anecdotal claims about the effectiveness of magnesium spray for things like sleep and muscle recovery are likely due to the placebo effect.
She adds it can be difficult to accurately judge the effectiveness of aids for sleep and recovery. “Recovery specifically is a very perceived feeling or effect, so it’s difficult to objectively measure the impact of a supplement.”
“[But] I believe some people will use these recovery methods and say they work, to which I say ‘That’s great. If it works for you, then keep doing it’.”
Magnesium spray for kids
Many proponents of magnesium spray promote it as a sleep aid for children. But Michael Gradisar, head of sleep science at Sleep Cycle, sees little need for magnesium supplementation in kids. He says it’s uncommon for children to be deficient in magnesium, as they can get more than enough from a well-rounded diet.
“To say that potentially magnesium could be a solution for kids flies in the face of scientific theory and evidence,” he says.
But Gradisar says he understands the attraction behind a quick fix such as magnesium spray, particularly for tired and frustrated parents.
Instead of reaching for something such as magnesium spray, Gradisar say parents whose children are having sleep difficulties should always seek the advice of a GP, who can refer them to a specialist if needed and help address the root cause of the issue.
“And the other big factor,” Gradisar adds, “is especially when kids get to school age, they start to have an increase in night-time fears and anxieties. And that’s also something that’s going to push sleep away and needs more specialised treatment. Magnesium just doesn’t cut it.”
While he doesn’t see any potential physical harm coming from the use of magnesium spray on children, Gradisar says there is the potential for psychological troubles down the line once the placebo effect wears off.
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