That’s why at BBC Mundo we decided to look at what is said online about the benefits of magnesium, what is true of everything that is said, and who is recommended to consume supplements.

The benefits attributed to magnesium in networks tend to be blunt: “improve your sleep now”, “relax instantly”, “relieve your anxiety”.

And for sleep psychologist Nathalia Padilla at the Johns Hopkins Institute of Medicine, it is understandable that this message draws attention, since there are many people who suffer from insomnia.

“People can spend years with insomnia trying to look for different things…and they’re drawn to solutions like magnesium because it’s so accessible,” he says.

The problem, he adds, is that in networks “they can take a single study… and sell it as something miraculous… and a person says ‘this is not going to do anything to you, it’s natural’.”

Padilla explains that, so far, there is not enough scientific information to ensure that magnesium helps people combat insomnia.

Nutritionist Calle agrees that it is best to proceed with caution when it comes to supplements.

Yes, magnesium participates in processes that we perceive as relaxation, but that does not make it a magic pill for anyone or in any dose:

“It helps to lower the intensity of neuronal excitation… and reduces the probability of arrhythmias… but all this depends quite a bit on how magnesium is already present,” says Calle.

Names abound on the shelf: citrate, bisglycinate, oxide.

What changes the most between them is absorption and tolerance, but the important thing is to discuss each case first with a doctor.

“Magnesium citrate is absorbed better than bisglycinate… there are other people who have better tolerance to bisglycinate,” explains Calle.

In practice, the form that is best tolerated and that clearly declares its content is chosen.

Here, both consulted by BBC Mundo insist on a simple criterion to avoid confusion: look at the label and look for elemental magnesium.

“The important thing is the amount of elemental magnesium that that presentation has, because based on that… I have to take into account what the appropriate doses are and what the dangerous ones are,” says Calle.

A bottle may claim “magnesium citrate 1,000 mg,” but that does not mean 1,000 mg of elemental magnesium.

Padilla adds another useful warning for buyers: supplements are not regulated like drugs so not all the information they provide necessarily includes all the relevant data.

For Padilla, there is still a lack of more knowledge about the benefits of magnesium supplementation for better sleep: “The literature is still limited… it has not been completely concluded that magnesium (as promoted) is going to completely help you with sleep.”

But it explains why it is believed that there may be a relationship between this mineral and our rest:

Magnesium is related to the GABA system – a neurotransmitter that promotes calm – and can “lower cortisol levels, which are anxiety and stress levels, and therefore improve sleep.”

There are specific cases in which it can facilitate rest indirectly. Padilla mentions a study with magnesium oxide in people with nocturnal leg spasms; If muscle discomfort is reduced, it is easier to sleep.

From physiology, Calle explains that magnesium “stabilizes neuronal excitability” and “counteracts the effects of calcium” in muscle and heart.

That is why someone with a deficiency of this mineral may feel calmer or have fewer cramps when they normalize their levels.

If these levels are already good, magnesium does not continue to add benefits, since the body tends to eliminate the excess.

For experts, it is clear that it is better to consume adequate amounts of magnesium through diet, and not rely on any supplement.

But if someone is considering a supplement, they caution against doing so “blindly.”

Calle explains that first it is necessary to know how magnesium levels are in the body, in addition to seeing how kidney function is.

The nutritionist highlights that although the kidneys get rid of the magnesium that we consume in excess, in very high quantities, or in people with kidney problems, the body can be overloaded.

He adds that, to avoid problems, it is important to measure the magnesium levels that the body has in principle. The reference figure he uses is “400 milligrams per day of elemental magnesium”, taking into account what foods already provide.

Padilla agrees, and prefers to move away from the idea that magnesium supplements help sleep.

It also lists those who should avoid it or use it only with supervision – such as people with kidney problems – and those with cardiovascular risks, because the supplement “can change heart rhythms, lower blood pressure.”

In high doses, he warns, effects such as nausea and diarrhea appear.

The good news – says Dr. Ricardo Calle – is that a varied diet is usually enough: “In a balanced diet, one has an adequate intake of magnesium most of the time.”

There’s no need to chase a single “superfood”; As he explains, the usual sources – vegetables, fruits and even some dairy products – provide similar amounts and, combined throughout the day, cover what is necessary.

Padilla, for his part, suggests looking toward Mediterranean-type patterns in the diet: “Consume foods like nuts, green vegetables like spinach, (and) certain types of fish like salmon.”

He says that it is important to clarify that if any food does not agree with you or you have digestive restrictions, it is important to adjust it with the help of a nutritionist so that the entire diet continues to provide the mineral.

On the daily table this translates into frequently adding green leaves (spinach sautéed or in a salad), adding a small handful of nuts, interspersing legumes and, a couple of times a week, including fish such as salmon. On that basis – and without the need for supplements – most people maintain their levels in an adequate range.

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