Written by Olivia Hunt
29th Nov 2022 • 4 minute read
Dr Nadja Auerbach
Reviewed by
Dr Nadja Auerbach, MBBS BSc Dip IBLM/BSLM

Magnesium is an important mineral involved in over 300 of your body’s processes. It’s essential for bone health, blood sugar control, and muscle and nerve function. You can take magnesium supplements to manage PMS symptoms, reduce inflammation, and support your body function.

Magnesium is a mineral that helps turn the food you eat into energy.  

It also ensures your parathyroid glands function correctly to produce hormones to support bone health.

Magnesium plays an important role in:

  • enabling your body’s cells to make proteins (protein synthesis)
  • muscle and nerve function
  • blood sugar control
  • blood pressure regulation

Magnesium can also protect you from developing high blood pressure (hypertension) and heart disease.

You can treat a deficiency or optimise your levels with our premium magnesium supplements.

What is magnesium good for?

Getting enough magnesium from your diet might be beneficial in preventing or treating certain health conditions, including: 

  • migraine headache frequency
  • metabolic syndrome — like type 2 diabetes 
  • high blood pressure (hypertension)
  • hyperlipidemia — when your blood contains too many lipids (fats), like triglycerides
  • asthma
  • premenstrual syndrome (PMS) symptoms — like negative thoughts, bloating, stress, and breast tenderness
  • depression
  • osteoporosis
  • poor sleep quality 

Studies have also shown magnesium has the potential to:

  • support muscle function and recovery
  • improve some PMS symptoms
  • relieve occasional sleeplessness

Magnesium is sometimes used in hospital settings. It’s usually administered into your vein (intravenously) to treat conditions like:

  • arrhythmias — when your heart beats out of rhythm
  • eclampsia — a condition that affects some pregnant women 
  • severe asthma 

How much magnesium do you need?

Currently, the recommended daily intake (RDI) of magnesium is 300mg a day for men (19 to 64 years), and 270mg a day for women (19 to 64 years).

If you’re taking a magnesium supplement to treat a deficiency, you must check with your GP that you have the correct dosage. 

Taking more than 400mg of magnesium for a short time might cause diarrhoea. This can happen if your supplement contains magnesium oxide or magnesium citrate, which can have more of a laxative effect.


The best type of magnesium supplements contain magnesium glycinate or bisglycinate — these are much easier for your body to absorb and are less likely to cause diarrhoea. 

Learn more about gut health and what you can do to support it.

When is the best time to take magnesium supplements?

You might find it helpful to take your magnesium supplement at the same time every day to start building a habit. 

Some people prefer taking a magnesium supplement with a meal in the evening, as it might improve sleep quality and relax your muscles. 

If you’re worried about when to take magnesium, your GP can give you advice.

What foods are high in magnesium?

Studies suggest 10-30% of people in the UK have a magnesium deficiency. This is because getting enough magnesium from a western diet with heavily processed and refined foods is difficult. 

But there are many good dietary sources of magnesium. These include:

  • green leafy vegetables — like spinach
  • legumes — like peanuts, edamame, and black beans
  • nuts — like cashews and almonds
  • peanut butter
  • seeds — like chia and pumpkin
  • whole grains
  • wholemeal bread
  • oats
  • some breakfast cereals — like shredded wheat
  • other fortified foods

Magnesium deficiency causes

Magnesium deficiency due to low dietary intake is rare if you’re otherwise healthy. 

But several health conditions can cause a magnesium deficiency. You might have a higher risk if you:

  • have type 2 diabetes — due to increased excretion of magnesium in your urine
  • have Crohn’s disease — a kind of inflammatory bowel disease (IBD)
  • have coeliac disease — your immune system attacks its tissues when you eat gluten
  • suffer from chronic alcoholism
  • are 65 years old or over — your gut absorbs less magnesium as you age
  • take certain medications that lower your magnesium levels
  • don’t eat many foods containing magnesium
  • consume high amounts of caffeine or alcohol — both use up your magnesium reserves

Magnesium deficiency symptoms

The early symptoms are vague, and as magnesium deficiency is uncommon, they may very well be due to other causes.  Symptoms include: 

  • loss of appetite
  • nausea or vomiting
  • fatigue
  • weakness

If your magnesium deficiency worsens over time, you might also suffer from:

  • numbness or tingling
  • muscle contractions and cramps
  • seizures — when abnormal electrical activity in your brain leads to fits
  • personality changes
  • abnormal heart rhythms (arrhythmias)
  • coronary spasms — sudden tightening of your arteries that send blood to your heart

If you have a severe magnesium deficiency, you might develop a calcium deficiency (hypocalcemia) or potassium deficiency (hypokalemia).

If you think you might have a magnesium deficiency, you should see your doctor for advice. They might run some blood tests to rule out any other health conditions.