Magnesium Supplements: Key Facts on Each Type

If you've spent any time on social media recently, you've probably found yourself wondering whether you should be taking a magnesium supplement. There's no shortage of influencers listing all the benefits that different types of magnesium supplements have - from boosting brain function to helping ease anxiety and improving sleep.

Indeed, magnesium is an essential mineral involved in hundreds of processes in the body. It helps muscles and nerves work properly, supports energy production and contributes to the maintenance of strong bones and teeth.

Magnesium is also important for maintaining a healthy heart rhythm, regulating blood pressure and blood sugar levels. Many people don't get enough from their diet , so supplements can be useful in some situations.

But when you look closely at the research, there's little evidence to suggest that any one type of magnesium supplement has unique benefits over another.

Magnesium glycinate

One of the most talked about types of magnesium is magnesium glycinate, often promoted as the best option for sleep. This form combines magnesium with glycine , an amino acid that may improve sleep on its own.

While some research does show that magnesium may improve sleep , these trials do not show that glycinate is any better than other forms. Glycinate's main advantage is that it's gentle on the stomach and well absorbed , which may make it easier for some people to tolerate.

Magnesium L-threonate

Another form that attracts a lot of attention is magnesium L-threonate. It's suggested it can improve memory and focus.

These claims appear to come from early animal studies which suggested that L-threonate may increase magnesium levels in the brain more effectively than other forms. In these studies, which were conducted in rats, supplementation enhanced several types of memory and increased the number and function of connections between brain cells in the hippocampus - a key region involved in learning and memory.

Human evidence remains relatively limited. One study did demonstrate that in people who took 2g of L-threonate daily for six weeks, the supplement was associated with improvements in several areas of thinking and memory - including working memory, memory of past events, reaction speed and overall mental performance.

But as the supplement was only compared against a placebo, the results cannot tell us whether L-threonate is more effective than other magnesium supplements when it comes to brain function.

Magnesium malate

Magnesium malate combines magnesium with malic acid, a compound involved in energy production within cells . Magnesium malate is often promoted for its purported ability to support energy levels and muscle function.

Magnesium in general is important for normal muscle and nerve function . Correcting a deficiency can improve symptoms such as fatigue and muscle cramps. But there's little evidence that magnesium malate offers advantages over other magnesium formulations - except that it's absorbed well .

Some small studies in people with fibromyalgia (a condition which causes widespread pain, extreme tiredness and problems with sleep) have reported that malate is associated with improvements in pain and fatigue. But there's currently no strong evidence that malate is superior to other well-absorbed forms of magnesium when it comes to improving muscle function or energy levels in the general population.

Magnesium citrate and oxide

Forms such as magnesium citrate and magnesium oxide are often used for constipation because magnesium draws water into the bowel.

Both forms may also reduce the severity and frequency of migraines and are cost-effective options. However, the oxide form is absorbed less efficiently, so people may need higher doses to achieve the same effect as citrate, which may cause an upset stomach.

Final verdict

Overall, across a range of clinical trials, magnesium has shown some benefits for sleep quality, anxiety symptoms , migraines and blood pressure . But there's no strong evidence that one form is better than another.

Many online claims that one types is more beneficial than another usually come from small pilot studies, animal research or supplement marketing - rather than large, well-designed human trials. Direct comparisons between different magnesium salts are lacking, so more research is needed to find out whether some types of magnesium do really work better than others.

While magnesium is beneficial for our health, it's worth asking whether supplements are even necessary. For most people, a varied and balanced diet is the best way to get magnesium. Foods with naturally high levels of magnesium include leafy greens (such as spinach and kale), nuts and seeds, wholegrains and beans. These foods provide fibre, antioxidants and other nutrients that supplements cannot offer. They also reduce the risk of taking too much magnesium, which can cause diarrhoea or stomach upset .

Those most likely to benefit from a magnesium supplement include people diagnosed with a deficiency, people with certain medical conditions (such as Crohn's disease, which affects the body's ability to absorb nutrients from food) and people who struggle to get enough magnesium from their diet.

For those who may benefit from a magnesium supplement, it's worth noting that some forms of magnesium - particularly magnesium citrate and glycinate - appear to be more readily absorbed by the body than others. Magnesium citrate is also recommended for treating a deficiency .

So even if two supplements contain the same amount of magnesium, the body may absorb more from one than the other. Factors including the dose and the presence of other nutrients (such as potassium and vitamin B6) can also affect absorption .

For most people, improving diet is a more sustainable approach to boosting magnesium levels.

Dipa Kamdar does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.