Magnesium is involved in more than 300 biological reactions in the body – in bone metabolism, in muscle contraction, and in brain health and function. It also helps regulate insulin levels and protein synthesis.
Magnesium is the second-most prevalent mineral in our cells, and around one-quarter of a body’s magnesium is found in muscle tissue, three-fifths in bone. Why then has it been hitting the news as one of the most key potential supplements to optimise our health? And how can we know if we're getting enough?
How to know if you need extra magnesium
NHS guidelines state that men need 300mg of magnesium a day, women 270mg. But to achieve this, do you need to take a supplement?
Many foods, including vegetables, fruits, legumes, nuts, seeds, chicken, milk, and salmon, contain magnesium. So unless your diet is low in these elements – more likely if you eat a lot of ultra-processed foods – you probably don’t need a supplement, particularly if you regularly eat home-cooked meals with varied colours (especially look out for green: spinach and kale are magnesium-rich).
A supplement might be useful for those whose lifestyle demands higher levels of magnesium – for example, athletes who need to generate energy for rapid limb movement and who lose magnesium through sweating.
As magnesium plays a role in muscle contraction, energy metabolism and electrolyte balance, a 2022 trial linked it to reducing muscle soreness after exercise, though further research is needed to understand the optimal timing and dosage.
Other groups who might benefit from magnesium supplements include sufferers of gastrointestinal diseases such as Crohn’s, type-2 diabetics, and the elderly – because the body’s ability to absorb magnesium decreases with age. If you’re in these cohorts, or are keen to take additional magnesium, the NHS suggests taking a supplement containing 400mg or less a day.
Can magnesium improve your sleep?
Emerging research suggests that magnesium may promote better sleep. A 2022 systematic review highlighted a possible association between magnesium status and sleep quality. So, if you do take a magnesium supplement, it may be best to take it in the late afternoon or evening, and to avoid calcium and zinc, which can impair absorption.
Some studies extol the benefits of transdermal magnesium – that is, a magnesium supplement applied to the skin via spray, oil, or cream. In fact, a 2024 study concluded that patients who struggle to absorb nutrients effectively due to bowel issues and who used a magnesium spray had steady or improved levels.
It’s worth noting that much research in this area is either non-independent or involves few participants. And, like many other minerals, magnesium may not be absorbed efficiently through the skin, so a spray may not be effective.
Always speak to a medical professional before taking supplements, especially if you have an existing medical condition.
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