A pharmacist has issued a stark warning to take care when buying a common supplement or it could seriously harm you. Magnesium is one of the various nutrients our body needs to function correctly.

Without it people can be left with muscle spasms, sickness, stiffness and fatigue – and failure to treat it can be far more serious leading to abnormal heart rhythms, seizures and even personality changes.

Obtaining adequate levels of magnesium requires maintaining a healthy and balanced diet that includes a variety of nutritious foods. Magnesium can be found in legumes, whole grains, leafy green vegetables like spinach, seeds, dairy products, or nuts.

However, despite being able to obtain magnesium naturally through our diet, we may sometimes fail to consume enough to maintain adequate levels of this nutrient. The mineral is essential for regulating muscle and nervous system function, blood sugar levels, and blood pressure, as well as contributing to protein formation, bone mass, and DNA.

But when it comes to topping up levels it is important to be aware the way it is taken is key to how well it works. Choosing the type of supplement that best suits you should be done under medical and expert recommendation since not all work the same way.

Pharmacist Carlota Serra Jorba explains this on her TikTok account, known as @conoceteysana, emphasising the importance of the chemical form of magnesium when taking it as a supplement. She says: “Generally speaking, we can say that magnesium has two functions: as a laxative and to promote, stimulate or normalise the central nervous system.”

She continues by indicating that depending on the chemical form in which magnesium is taken, it will serve one purpose or another. She said: “In citrate or carbonate form, magnesium will not be absorbed; therefore its function will be laxative. If you are looking for it to normalise the central system or use it as a muscle relaxant, you need to look for chemical forms that are absorbed, such as magnesium glycinate or bisglycinate.”

According to the NHS most people should be able to get the amount of magnesium from their diet. It is found in a wide variety of foods, including:

  • spinach
  • nuts
  • wholemeal bread

Men, aged 19-64 need 300mg a day while women of the same age need 270mg a day. The Department of Health and Social Care says: “Taking high doses of magnesium (more than 400mg) for a short time can cause diarrhoea. There’s not enough evidence to say what the effects might be of taking high doses of magnesium for a long time.

“You should be able to get all the magnesium you need by eating a varied and balanced diet. If you take magnesium supplements, do not take too much as this could be harmful.”

However it adds: “Having 400mg or less a day of magnesium from supplements is unlikely to cause any harm.”