Does magnesium help tiredness?
Maybe, if you’re low in it. UK labels may say magnesium cuts tiredness. But the clearest trial result in tired people came from jabs, not tablets.
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Does magnesium help with tiredness?
Maybe, if you’re short of it. The NHS says magnesium helps turn the food we eat into energy. It also says a varied, balanced diet should give you all you need.
The clearest result is from a 1991 UK trial in 32 people with chronic fatigue syndrome. Of 15 given magnesium, 12 said they’d benefited. Only 3 of the 17 on a dummy treatment said they felt better.
That trial used weekly jabs into muscle, not tablets. In the same study, people with the condition had lower magnesium in their red blood cells than healthy people.
| Trial | Who and what | What it found |
|---|---|---|
| UK, 1991 | 32 people with chronic fatigue syndrome. Magnesium jabs every week for 6 weeks, or a dummy. | 12 of 15 on magnesium said it helped, against 3 of 17 on the dummy. |
| Spain, 2025 | 89 people with fibromyalgia finished. CoQ10, tryptophan and magnesium, or a dummy pill. | Tiredness got clearly better on the dummy pill (each person had both, in turn). The fall on the supplement was too small to count. |
| Iran, 2026 | 98 adults with bowel disease (IBD) that was calm at the time. B vitamins plus magnesium for 4 weeks, or a dummy. | Tiredness scores fell more on the supplement. Nobody can tell which part did it. |
Sources: Cox 1991; Rosselló Aubach 2025; Ramezani 2026
For long-term fatigue (ME/CFS), NICE says there’s not enough evidence to take vitamin and mineral supplements routinely to manage symptoms.
So before you buy, check the signs of low magnesium.
Why do labels say magnesium cuts tiredness?
Because GB rules allow the words “Magnesium contributes to a reduction of tiredness and fatigue”. Any food that is at least a source of magnesium can use them.
The GB list of allowed claims sets the wording and when it can be used. It gives no trial results and no dose for tiredness.
So read the claim as “this has magnesium in it”. Then check the magnesium line in the nutrition table against the NHS amounts below.
Choosing a form? See which magnesium to take.
What else could be making me tired?
The NHS lists the common causes first. They include poor sleep, stress, low mood, an unhealthy diet, little exercise and hormone changes.
Some illnesses and medicines cause it too. Other symptoms can point to a cause.
| Tiredness plus | Possible cause |
|---|---|
| Waking at night, gasping, snorting or choking noises, loud snoring | Sleep apnoea |
| Lack of energy, a heartbeat you notice, short of breath, pale skin | Iron deficiency anaemia |
| Very thirsty, peeing more often than usual (especially at night), weight loss | Diabetes |
| Hard to stay still, nervous, anxious, irritable, weak muscles | Overactive thyroid |
| Extreme tiredness for at least 3 months that makes daily life very hard, problems with thinking, memory and concentration, flu-like symptoms | ME/CFS |
Source: NHS
Take a stomach acid tablet such as omeprazole or lansoprazole? Rarely, these have been linked to severe low magnesium, mostly after a year of use. The MHRA lists tiredness among the signs.
A GP may suggest blood tests for anaemia, diabetes or an overactive thyroid. See blood tests for fatigue, the magnesium blood test and blood tests on omeprazole.
How much magnesium is safe to take?
You need 300mg a day if you’re a man and 270mg if you’re a woman, aged 19 to 64. Spinach, nuts and wholemeal bread all have it.
- 400 mg a day or belowNHS: unlikely to cause any harm.
- Above 400 mg a dayMore than 400mg can cause diarrhoea.
Source: NHS
Have kidney problems? Ask your GP first, because magnesium can build up in your blood.
Magnesium can stop some medicines being taken in properly. These include some antibiotics, levothyroxine, iron tablets and bone medicines. The UK medicine sheet for a magnesium medicine says to take them about 2 to 3 hours apart.
Ask a pharmacist if you take any of these. Never stop or change a prescribed medicine without your prescriber. More in can you take too much magnesium.
What can I do about tiredness now?
Six NHS tips to try this week
- Go to bed and get up at the same times, and aim for 6 to 9 hours of sleep.
- Eat regular meals and healthy snacks every 3 to 4 hours, rather than one large meal.
- Take a 15-minute walk, then build up to 2 hours 30 minutes of moderate exercise a week.
- Skip caffeine in the evening. Its effects can last up to 7 hours.
- Keep alcohol to 14 units a week or less, with several alcohol-free days.
- Drink a glass of water, especially after exercise. Mild dehydration can make you tired.
Sources: NHS: tiredness and fatigue; NHS: self-help tips to fight tiredness
Stress and low mood use up energy too. The NHS says talking therapies such as CBT (a therapy that helps you change unhelpful thoughts) might help.
Waking up tired after a full night? See still tired after sleep.
When to speak to a GP
Don’t let a supplement put off a check. Speak to a GP if:
- You’ve been feeling tired for a few weeks and you’re not sure why.
- Your tiredness affects your daily life.
- You feel tired and have other symptoms, such as weight loss or mood changes. Or you’ve been told you make gasping, snorting or choking noises in your sleep.
- You take an acid-reducing tablet such as omeprazole and get muscle twitches, tremors, vomiting, tiredness or loss of appetite. The MHRA says to see your doctor.
- You have kidney problems and want to take magnesium.
Low on iron rather than magnesium? See the iron deficiency blood test guide.