Do you really need magnesium supplements?

Magnesium has been getting a lot of press lately for everything from sleep support to mental health.

But most people shouldn't need a supplement to get enough, and the evidence for some of these claims is somewhat limited.

Here we explain why it's important, the signs of a magnesium deficiency to be aware of, and what to know about magnesium supplements. 

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Why magnesium matters

Magnesium plays a key role in maintaining processes that regulate our bodies, including bone, nerve and muscle health, as well as blood pressure and blood sugar levels.

It can be found in foods such as green leafy veg, nuts, wholegrain bread or rice and avocados.

Magnesium deficiency symptoms

Magnesium deficiency isn't that common, but some studies suggest it can increase the risk of illnesses such as heart disease, osteoporosis and type 2 diabetes if left untreated. Symptoms are often mild to begin with and easy to overlook, as they can be confused with common illnesses.

Some of the symptoms of magnesium deficiency include nausea or vomiting, loss of appetite, fatigue or weakness, muscle weakness, twitches and cramps and in later stages abnormal heart rhythms or coronary spasms.

If you're experiencing symptoms, you should discuss these with your GP to rule out other potential causes.

How much magnesium do you need per day?

NHS guidance on magnesium says that:

• Men (19-64 years old) need 300mg of magnesium per day 
• Women (19-64 years old) need 270mg of magnesium per day

Pumpkin seeds will give you the most bang for your buck, according to the US National Institute of Health's list of magnesium-rich foods, with nuts such as cashews and peanuts close behind. Potatoes, brown rice, oatmeal and some cereals are also big hitters with around 50mg per serving

Taking too much magnesium (over 400mg in a short time according to the NHS), may lead to adverse side effects, including diarrhoea. There isn't much information on the adverse effects of taking high amounts long term, so it's best to err on the side of caution.

Who is most at risk of magnesium deficiency?

You may be more at risk of developing a magnesium deficiency if your diet is unbalanced or restricted. 

Some people can develop one as a result of an underlying health condition or medications. These include gastrointestinal conditions such as Crohn’s or coeliac disease, poorly controlled type 2 diabetes, kidney disorders, chronic alcoholism or certain medications – such as proton pump inhibitors (PPIs) and diuretics.

Older people may also have lower levels due to increased difficulty absorbing it from their diet, and reduced appetites.

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Which foods are high in magnesium?

If you want to ensure you're getting enough magnesium in your diet, make note of the foods which have higher levels, and try to incorporate these where possible. 

Magnesium-rich foods include:

• Green, leafy vegetables (such as spinach)
• Pumpkin, sesame and sunflower seeds
• Wholegrain bread and brown rice
• Almonds, cashews, peanuts and brazil nuts
• Avocados
• Bananas
• Tofu
• Beef, chicken, fish and seafood
• Dairy products
• Dark chocolate

Switching to wholegrain is a simple way to up your intake, and green leafy veg, bananas and dairy products are some of the cheaper options to swap in.

A handful of high-magnesium seeds or nuts, either as a snack or sprinkled over a meal, is a handy way to up your levels.

What to know about magnesium supplements

Magnesium is known to play an important role in the body, and it has approved health claims for contributing to reduction of tiredness and fatigue, maintaining energy levels, electrolyte balance and protein synthesis, normal functioning of the nervous system, muscle and bone function, psychological function and teeth. 

However, the evidence for its role as a sleep aid is less concrete, despite what some social media recommendations may lead you to believe. Sleep expert Professor Guy Leschziner told us that there is currently limited evidence to suggest it can help. 

The relative cheapness of basic magnesium supplements, and their general safety profile (provided you aren't on other medication), means it could be worth a try if you're struggling with sleep. However, before turning to supplements, check out the proven ways to improve your sleep that our expert recommends in our full guide to sleeping better.

The same applies to magnesium's role in aiding anxiety. While some studies have shown some improvement in self-reported anxiety, better evidence is needed to show conclusive impacts.

In all cases, a food-first approach is best and, if you do decide to take supplements, it's best to talk to your GP first – especially if you are currently taking any medication in case of possible interactions.

Types of magnesium supplement

Magnesium supplements are widely available in many different formats, which can be a bit confusing. Essentially, magnesium needs to be combined with other sources in order to be absorbed by our bodies, and these all have slightly different characteristics.

Some are aimed at supplementing low levels and associated issues (such as muscle aches), but others can also help with heartburn or work as a laxative.

The main combination forms include:

• Magnesium oxide – commonly used for oral supplements.
• Magnesium glycinate – magnesium and glycine, an amino acid which helps support the central nervous system. 
• Magnesium citrate – magnesium and citric acid. Some studies claim it is more easily absorbed than other types.
• Magnesium malate - combined with malic acid. 
• Magnesium sulphate – also known as Epsom salts. Most often designed for absorption through the skin, eg via a bath, but oral versions are available.
• Magnesium chloride – used in baths, gels and lotions, but can also be taken orally. Small-scale studies suggest it is also more easily absorbed.

Where to buy magnesium supplements

If you do need to take supplements, most pharmacies, health stores and supermarkets have a range of options to choose from. 

Magnesium tablets and gummies usually contain magnesium citrate or oxide. Gummies may be easier if you don't like swallowing pills, but they're typically pricier and may contain added sugar.

Soluble magnesium – effervescent tablets that you dissolve in water – usually contain magnesium citrate or glycinate. They may also contain additional sugars, salt or flavourings. They're typically around £5-£15 per pack.

Magnesium sprays, gels and lotions can be applied directly to the skin. These usually contain magnesium chloride, and will cost anywhere from £10-£20 per bottle. Magnesium flakes and bath soaks can be bought in smaller bags or large tubs, and will typically set you back between £10 and £30.

Always buy from a trusted retailer. Some of the most popular options are listed below:

• Boots has everything from own-brand tablets to branded multivitamins containing magnesium from Centrum and Osteocare. You can also expect to find soluble magnesium, lotions and oral sprays.
• Holland & Barrett stocks magnesium oils, multivitamins, capsules, gels and effervescent tablets.
• Superdrug has an online range of around 20 magnesium-related products, including Centrum, Wellwoman and Pregnacare. It sells gummies, capsules, oils and multivitamins.

You'll also find a selection at supermarkets, including own-brand and branded supplements, sprays and tablets. 

The cheapest we found were at Asda for just under 7p a tablet (£2 for a pack of 30), but Sainsbury's and Tesco aren't far behind at 7p per tablet (same as Boots' own-brand option), and you may be able to get loyalty points or multi-buy offers.

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