For more than a decade, Kendall Platt worked as a crime scene forensic investigator – a job she found rewarding but also intensely stressful.

The 40-year-old mother of two says she would often lie awake at night thinking about the horrific images she had seen that day. Her sleep, unsurprisingly, suffered.

‘I would have bad dreams most nights and wake up sweating,’ says Kendall, from Reading. ‘And once that happened, I’d struggle to get back to sleep.’

So when, last year, Kendall changed career to become a professional gardener – offering what she describes as horticultural therapy to women – she expected her sleep to improve.

Moreover, desperate for a better night’s rest, Kendall also cut down on the amount of sugar she consumed and stopped looking at her phone in the hour before bedtime.

However, these changes did not have the effect she had hoped.

‘I was still waking up at 3am and lying awake for hours,’ she says. ‘Then the kids would wake up at 6am and I’d be up again, meaning I was getting very little sleep.’

Then, Kendall says she found a solution: a daily 10p dose of the vitamin magnesium.

Experts say magnesium is one of the most important nutrients our bodies need – but around one in six Britons do not get enough.

For more than a decade, Kendall Platt worked as a crime scene forensic investigator – a job she found rewarding but also intensely stressful

And, increasingly, magnesium tablets have been touted as a sleep-boosting supplement, leading to an explosion in its popularity, with this rising interest driven primarily by social media.

However, many doctors now also recommend magnesium for patients with sleep problems – based on what they believe is growing evidence that the supplement has a profound effect on rest and energy levels.

Kendall says she first learned about the sleep benefits of magnesium through social media. As a result, two months ago, she decided to give it a go, buying effervescent magnesium tablets from her local supermarket. The tablets contain a particular form called magnesium glycinate, which is thought to be most effective at improving sleep quality.

Kendall would place one of the tablets in water and drink it an hour before going to bed.

The effect was immediate. ‘I started waking up refreshed,’ she says. ‘My sleep has been consistently good for two months now.

‘I do occasionally wake up in the night, but I can easily drop off back to sleep in a way that I could not before.

‘I have more energy in the morning when I’m getting the kids ready for school. And I’ve got way more energy at work too.’

However, not everyone agrees that magnesium is a panacea for poor sleep.

In fact, some experts believe that the supplement has no effect at all.

So, do magnesium supplements really improve sleep – and should you be taking one?

The need for more sleep remedies is clear. Studies suggest that around a third of Britons suffer from insomnia – meaning they struggle to sleep. Meanwhile a quarter of people say they feel tired most of the time, regardless of how much sleep they get.

Experts say that it is this energy level crisis that has spurred the increasing popularity of magnesium.

Magnesium is found in leafy green vegetables as well as cashew nuts, beans and wholemeal bread. It is crucial for the muscles, immune system, bone strength and blood sugar levels.

Experts say magnesium is one of the most important nutrients our bodies need – but around one in six Britons do not get enough

Magnesium’s effect was immediate. ‘I started waking up refreshed,’ she says. ‘My sleep has been consistently good for two months now’

In 2021, a major review of dozens of magnesium sleep studies concluded that patients with higher levels in their blood tended to sleep for longer and have more energy – though the effect was small.

Dr Oliver Bernath, a consultant neurologist at Guy’s and St Thomas’ Hospital and the Reborne Longevity clinic, both in London, argues that magnesium’s profound effect on sleep is that it boosts levels of a chemical called gamma-aminobutyric acid, which has a calming effect on the brain.

‘I’ve seen the really positive effect that magnesium can have for my patients with sleeping issues,’ he says.

Not all scientists agree. Dr John O’Neill, a biologist at the Laboratory of Molecular Biology in Cambridge, says that the only patients likely to benefit from taking magnesium supplements are those who have markedly low levels of the nutrient.

‘Your body can only hold so much magnesium,’ he says. ‘If a patient has normal levels and they take a supplement, then that extra magnesium will just be peed out.’

Instead, Dr O’Neill claims that it is more likely that patients who find their sleep improves after taking magnesium are experiencing the placebo effect – where they believe their symptoms have improved despite the medicine having no impact.

‘Most sleep issues are down to the stresses and anxieties of life, rather than vitamin deficiencies,’ he says.

‘A placebo can often be a very powerful treatment. Magnesium is also cheap and very safe, so there are few harms in taking it.’

Kendall says she doesn’t care whether or not her magnesium tablets are a placebo.

‘The effect is clear to me – it works and other steps haven’t,’ she says. ‘So to me, it’s worth it.’