Nutrient deficiencyOne of 30 articles on this topicAll minerals at a glance

Magnesium deficiency: symptoms, causes and treatment

Calf cramps, a twitching eyelid, inner restlessness? A magnesium deficiency rarely comes from your plate alone; usually losses through medication, alcohol or diarrhoea add to it. Find out which symptoms are typical, why the blood level only tells half the story and what helps.

Gregor AßlaberJoerg Hauke
Gregor Aßlaber, Editor, Saturo · ✓Fachlich geprüft von Joerg Hauke, Nutrition expert
Aktualisiert 24 September 2026 · 16 Min. Lesezeit · 70 Quellen
In 30 seconds
Magnesiumreiche Lebensmittel auf hellem Stein: Haferflocken, Kürbiskerne, Sonnenblumenkerne, Mandeln, Cashews, Banane, Zartbitterschokolade, Spinat, weiße Bohnen, Makrele, Parmesan, Vollkornbrot und Feigen
12MgMagnesium
Magnesium sources at a glance: oat flakes, pumpkin seeds, sunflower seeds, almonds, cashews, banana, dark chocolate, spinach, white beans, mackerel, Parmesan, wholemeal bread and figs.

The key points in 30 seconds

Daily requirement
300–350mg

DGE estimates: 300 mg for women, 350 mg for men, including during pregnancy and breastfeeding. With wholegrains, nuts and pulses, you can reach this without a supplement.

One in seven
14.5%

That's how many people in a German study of 16,000 had a blood magnesium level that was too low, with women and older people affected more often. Mostly without anyone noticing.

Of which in the blood
1%

Your body holds around 24 g of magnesium, 60% in the bones and 27% in the muscles. Blood shows only a fraction, so your level can look normal while your stores run empty.

The silent thief
Acid blockers

If you take proton pump inhibitors for heartburn for longer than a year, your risk of magnesium deficiency is up to 1.8 times higher. The US drug agency has been warning about this since 2011.

01 Recognise

Magnesium deficiency symptoms: how to spot it

Magnesium slows the inflow of calcium into nerve and muscle cells, so a deficiency shows up where signals flow: as calf cramps, a twitching eyelid, tingling or inner restlessness. Doctors speak of hypomagnesaemia below about 0.75 mmol/l in blood serum. Because only around one percent of your magnesium circulates in the blood, a mild deficiency often goes unnoticed; below 0.5 mmol/l potassium and calcium drop too, and then cramps and skipped heartbeats can follow.
Interactive

Which signs do you recognise in yourself?

Tap what applies to you. You'll then see how many typical signs add up.

Not a diagnostic tool. All of these signs have many possible causes. Only a blood test gives you certainty. For seizures, a persistently racing heart or impaired consciousness: call emergency services.

First signs: calf cramps, twitching, tiredness

The first signs are unspectacular: the DGE (German Nutrition Society) lists loss of appetite, nausea, tiredness and weakness. Then your muscles join in with night-time calf cramps, a fluttering eyelid and a tense neck. Without enough magnesium, the nerve membrane stays more permeable to calcium and the muscle fires when it shouldn't. The exhaustion comes from the fact that ATP, the energy molecule, only works as a magnesium complex. A single calf cramp or two days of eyelid twitching isn't a deficiency. What counts is the combination over weeks, together with a cause.
Woman at a desk pressing two fingers to her twitching eyelid: eyelid twitching is a common early sign that can be caused by a magnesium deficiency
The fluttering eyelid is the best-known magnesium symptom, and the one most often misread: usually it's lack of sleep, screens and caffeine behind it, not the mineral.

Magnesium deficiency: neurological symptoms

Because magnesium sets the stimulation threshold of your nerves, the neurological signs are the most reliable, and they come in stages. Mild: tingling and numbness in your hands, feet or around your mouth, fine tremors, visible muscle twitching. Moderate: heightened reflexes, cramps that you can't stretch out, confusion in older people. Severe: tetany with cramped hands and feet, and in extreme cases seizures. Two simple tests make it visible: if the corner of your mouth twitches when someone taps in front of your ear, that's Chvostek's sign; if your hand curls into a paw-like position under a blood pressure cuff, that's Trousseau's sign.

Magnesium deficiency: eyes, face and vision problems

The twitching eyelid is the most searched-for symptom. Magnesium can play a role, but the everyday triggers are lack of sleep, screens, caffeine and stress, and the fluttering usually disappears by itself after a few days. In your face, a real deficiency tends to show up as a twitching corner of the mouth or tingling around the lips. The medical literature doesn't know of any direct eye symptom: flickering or flashes of light are usually a migraine aura, and migraine is more common when magnesium status is low. Sudden blurred vision or double vision should be seen by an eye doctor promptly.
When to see a doctor

If you have cramps with tingling, heart palpitations or confusion while taking acid blockers or water tablets, during chemotherapy, or after days of diarrhoea, go to your doctor's surgery promptly: magnesium, potassium, calcium and an ECG. Call 112 for a seizure, tetany, persistent racing heart or impaired consciousness.

Magnesium deficiency and the heart: palpitations and rhythm disorders

Your heart muscle needs magnesium to relax after every beat; it keeps the potassium channels of the heart cells tight. If your level drops, you get extra beats that feel like stumbling, and a pounding heart. The dangerous form is torsade de pointes. It's rare, but here magnesium is the emergency drug: in a classic study, two grams of magnesium sulphate as an infusion stopped it within minutes in nine of twelve patients. People with heart failure, people taking diuretics or digitalis, and anyone with low potassium are at risk.

Magnesium deficiency symptoms: mental health

Inner restlessness, irritability, poor sleep and trouble concentrating make up the mental picture. In the brain, magnesium dampens the excitatory messenger glutamate; without enough of it, your nervous system reacts more sensitively to stress. The evidence is weaker than the promises: in a study of 126 adults with mild depression, 248 mg a day improved the depression score by six out of 27 points in six weeks, though without a placebo. For sleep, three small studies in older people show falling asleep 17 minutes sooner. A magnesium deficiency does not cause depression.

Magnesium deficiency symptoms: women

The symptoms are the same in women and men; the situations differ. In the German study of 16,000 people, women more often had a low level. In pregnancy and breastfeeding the estimated requirement stays at 300 mg, and severe vomiting can push your level down. For PMS, an analysis of observational studies found no link with the blood level. During the menopause, sleep problems and palpitations overlap with hormonal symptoms, and from 60 acid blockers and thiazides come into play.
02 Causes

Magnesium deficiency causes: where it comes from

There are three routes into magnesium deficiency: too little going in, too little absorbed, too much going out. The first is rarer than you'd think: according to the national consumption survey, average intake of 432 mg (men) and 361 mg (women) is above the estimated values, and only about a quarter of adults fall below, mostly those eating white flour, ready meals and little veg. The more common route to a measurable deficiency is losses via the gut and kidneys.
Interactive

How much magnesium do you need per day?

170mg per day

Child 1–3 years: Toddlers need 170 mg, 4- to 6-year-olds 190 mg, 7- to 9-year-olds 240 mg, and 10- to 12-year-olds 260 mg (boys) and 230 mg (girls). Porridge, wholemeal bread, a banana and milk cover that without any planning.

Estimated values for adequate intake from the DGE (2021 derivation). They apply to healthy kidneys and normal absorption. With bowel conditions, or while taking acid blockers or water tablets, your needs may be higher; with reduced kidney function, follow your doctor's advice.

Magnesium thieves: medicines that drain magnesium

The most common hidden cause is acid blockers: proton pump inhibitors such as pantoprazole and omeprazole slow down absorption in the gut. Since 2011, the FDA has warned about cases, mostly after more than a year of use, with tetany, rhythm disorders and seizures, where a supplement alone wasn't enough; in nine studies with over 115,000 people, the risk was 1.8 times higher. Water tablets such as furosemide and thiazides flush magnesium out via the kidneys. With cisplatin, the antibodies cetuximab and panitumumab, ciclosporin and tacrolimus, monitoring is part of the treatment.

Alcohol, gut, diabetes: the big routes of loss

Alcohol acts acutely like a magnesium diuretic: even one evening with several drinks makes your kidneys excrete more for hours; the S3 guideline on alcohol withdrawal lists magnesium alongside vitamin B1. Through the gut, magnesium is lost with chronic diarrhoea, coeliac disease, Crohn's disease, after bowel surgery or a gastric bypass, and with daily laxatives. With diabetes, sugar in the urine pulls minerals out with it: depending on the study, 13 to 48% of people with type 2 diabetes have a level that's too low. A special case is refeeding syndrome: after prolonged starvation, phosphate, potassium and magnesium crash within days as you start eating again.
Stress, exercise, sweating: myth or cause?

Three supposed culprits are smaller than their reputation. Sweat: 1 to 10 mg per litre, so two litres cost 20 mg at most. Coffee: about 4 mg net per day. Stress: the vicious-circle theory rests on small studies, and the most-cited review was funded by a supplement manufacturer.

Rare causes: kidneys, hormones, genes

  • Hereditary kidney disorders: in Gitelman and Bartter syndrome, the kidneys permanently lose magnesium and potassium. They're usually discovered in adolescence because of cramps.
  • Familial hypomagnesaemia: mutations in the magnesium channel TRPM6. Very rare, and it shows up in infants with seizures.
  • Hormones: excess aldosterone (Conn syndrome), overactive parathyroid glands, untreated overactive thyroid.
  • Acute situations: severe pregnancy sickness, major burns, pancreatitis, artificial feeding without added magnesium.
03 Understand

How your body keeps magnesium in balance

Three stages from plate to kidney. Once you know them, you'll understand why the blood level says so little about your stores, why a deficiency drags potassium and calcium down with it, and why acid blockers and diuretics do more damage than a low-magnesium day.

1

Absorption in the gut

Of the roughly 370 mg a normal day provides, the small intestine absorbs 30 to 50%, partly passively between the cells, partly actively via the TRPM6 channel. The rate adapts: when intake is low it rises to as much as 80%, when intake is high it falls to 20%. Phytate from wholegrains and oxalate from spinach slow absorption down, and spread across the day more gets through than all at once. In one measurement, magnesium from almonds was absorbed just as well as from a supplement.

2

Stores in bones and muscles

Your body holds about 24 g of magnesium: a good half in the bones, a quarter in the muscles, the rest in other cells, and only around one percent outside the cells, of which the lab measures a fraction. Bone is the buffer: if your food lacks magnesium, it gives some up, and the blood level stays normal for weeks. According to the DGE, serum magnesium only drops after more than 80 days of undersupply. So the blood level is a window, not a bank balance.

3

The kidney decides

Every day the kidney filters around 2,400 mg of magnesium and reclaims 95% of it; only about 100 mg ends up in the urine. The loop of Henle recovers most of it, while the distal tubule does the fine-tuning using the same TRPM6 channel as the gut. This is exactly where diuretics, alcohol, cisplatin and high blood sugar act. And this is where the domino effect starts: if the kidney cells lack magnesium, the potassium channels open and potassium drains away; at the same time the deficiency blocks parathyroid hormone, and calcium falls.

04 Diagnosis

Magnesium level: how a magnesium deficiency is diagnosed

Your magnesium level is measured in blood serum, in millimoles per litre (1 mmol/l equals 2.43 mg/dl). 0.75 to 0.95 mmol/l is usually considered normal, though some labs only start at 0.65. Below 0.75, hypomagnesaemia begins. How serious it is depends less on the number than on two questions: Do you have symptoms in your muscles, nerves or heart? Have potassium and calcium dropped too? The three stages point the way.

The three stages of magnesium deficiency

  1. 1 Mild0.65–0.75 mmol/l

    Usually no symptoms, and the most common finding. Find the cause (medication, alcohol, gut, blood sugar), have potassium and calcium measured too, and correct it with magnesium-rich food and, if needed, a supplement. Recheck after four to eight weeks.

  2. 2 Moderate0.5–0.65 mmol/l

    Muscle twitching, cramps, tingling and tiredness become likely, and potassium and calcium often drop too. Needs medical treatment, usually oral magnesium over several weeks. Remove the cause, and get an ECG if you have heart palpitations.

  3. 3 Severe< 0.5 mmol/l

    Tetany, heart rhythm disorders and seizures are possible. Treated in hospital with magnesium sulphate by infusion under ECG monitoring, and potassium and calcium are corrected at the same time.

Classification based on the review papers by Jahnen-Dechent and Ketteler (2012) and Gröber et al. (2015). The DGE gives 0.5 mmol/l as the threshold below which symptoms typically occur. With heart complaints or signs of cramping, the symptom counts, not the stage. Some labs set their own reference ranges; if so, go by your lab's.

Magnesium deficiency test: blood level, urine, home test

The serum level is the standard, available at any GP practice. Its weakness: it only shows the small fraction currently circulating in your blood. Ionised magnesium is more accurate, but only a few labs measure it. The 24-hour urine test shows where the magnesium is going: if your kidneys excrete a lot despite a low blood level, the cause is there, otherwise it's in the gut. The level in red blood cells isn't validated, home tests by finger prick measure the same thing as the practice, and there's no urine test strip.
A medical assistant draws blood from a patient at a GP practice: the magnesium level is measured in blood serum
Serum, potassium, calcium and, if needed, urine: four values that show whether you have a magnesium deficiency and where the magnesium is going.

Can you have a magnesium deficiency even if your blood values are fine?

Yes. Around 99% of magnesium sits in bones, muscles and cells. If you take in too little over several weeks, the bones release some, and your blood level stays normal until the reserve shrinks. Since 2016, one research group has proposed raising the lower limit to 0.85 mmol/l. A value at the low end, plus symptoms, plus a loss situation is a reason to find the cause, counteract it for four to eight weeks and measure again. A value above 0.85 without symptoms is no reason for a supplement.

Screening without a reason achieves little, because in healthy people the kidneys keep the level stable. Testing makes sense when a loss situation (acid blockers, diuretics, diabetes, diarrhoea, bowel disease, alcohol) coincides with symptoms. It's always worth it for a potassium deficiency that doesn't rise despite potassium intake, or a calcium deficiency with no obvious cause: magnesium is often behind both.
Before the test

Don't take a high-dose supplement in the days beforehand, as it raises the blood level and hides the cause. Bring your list of medications. Ask for potassium and calcium to be tested too. Don't pump your fist during the blood draw, as it skews the values upwards.

05 Treatment

Fixing a magnesium deficiency: what really helps

Treatment has two parts: remove the cause, refill the stores. A mild deficiency can often be corrected with four to eight weeks of magnesium-rich food. From a moderate deficiency, doctors prescribe 4 to 6 mg per kilogram of body weight a day by mouth, for weeks to months. A severe deficiency is treated in hospital by infusion. If potassium or calcium is low at the same time: magnesium first.

Fixing a magnesium deficiency: food or tablets?

It depends on the cause. If it's down to your plate, food is enough: 30 g of pumpkin seeds provide 178 mg, 150 g of cooked spinach 131 mg, 200 g of white beans 126 mg. If the cause is a medication, your gut or your kidneys, you lose more than your gut can replace. Then a supplement is the tool, dosed by a doctor and rechecked after four to eight weeks. With a normal level and just calf cramps, a Cochrane review of eleven studies found it does nothing measurable, but it causes diarrhoea in one in ten to one in three people.

A low magnesium level needs a cause first. Usually it's a medication, your gut or your blood sugar, not your plate. If you skip that and just swallow tablets, you're treating the lab value, not the person.

Joerg Hauke, Nutrition expert, subject-matter review of this article

What helps quickly with a magnesium deficiency?

Nothing off the shelf. Only an infusion in hospital works fast. On a supplement, your blood level rises within days to weeks, but your body refills bones and muscles first. A 2021 review puts the time to reach balance at 20 to 40 weeks. The only thing you can do straight away is stop the loss: get your acid blockers reviewed, pause alcohol, drink an electrolyte solution if you have diarrhoea, and get your blood sugar under control (the American Diabetes Association advises against chromium for that). Doubling the dose only gives you diarrhoea.

Magnesium tablets: dosage, compound, side effects

Two different worlds: food supplements with a maximum of 250 mg per daily dose (BfR) for healthy people with a gap in their diet, and medicines with 300 to 600 mg for a measured deficiency, dosed by a doctor. When it comes to the compound, the data is clearer than the advertising: in a 60-day study, magnesium oxide did no better than placebo, citrate was absorbed much better, and chloride, lactate and aspartate were on a par. For glycinate, malate or taurate, there are no comparative studies in humans. More important than the compound is taking several small doses with food. If you get diarrhoea, the typical side effect, lower the dose.
Not on your own

If your kidney function is reduced, only take supplements after talking to your doctor, otherwise you risk an excess, with a drop in blood pressure, muscle weakness and heart rhythm problems. Magnesium binds tetracyclines, quinolones, bisphosphonates and L-thyroxine in the gut (thyroxine absorption minus 12% in one study): stick to the gap between doses given in the product information.

06 Nutrition

Magnesium foods: what contains a lot of magnesium

Magnesium sits in chlorophyll and in the germ: in everything that's green and everything that can sprout. The richest sources are seeds, nuts and cocoa, then wholegrain and pulses, then leafy greens. Animal foods play a supporting role, apart from oily sea fish. In everyday life, according to the consumption study, most magnesium comes from drinks, bread and dairy, simply because we consume so much of them. The ranking shows both sides per 100 g, and the notes give the portions.

Magnesium per 100 g: top 10 plant-based and animal

  1. Hemp seeds (hulled): 700 mg
  2. Wheat bran: 611 mg
  3. Pumpkin seeds: 592 mg
  4. Cocoa powder (unsweetened): 499 mg
  5. Flaxseed: 392 mg
  6. Brazil nuts: 376 mg
  7. Sesame: 351 mg
  8. Chia seeds: 335 mg
  9. Sunflower seeds: 325 mg
  10. Cashews: 292 mg

Values per 100 g dry, USDA FoodData Central SR Legacy. Seeds and cocoa lead because they contain no water. On your plate, portions are what count: 30 g pumpkin seeds 178 mg, 30 g almonds 81 mg, 50 g rolled oats 69 mg, 150 g cooked spinach 131 mg, 200 g cooked white beans 126 mg, 200 g wholewheat pasta 108 mg, two slices of wholemeal bread 60 mg, 20 g dark chocolate 46 mg, one banana 32 mg. For comparison: 200 g wheat pasta 36 mg, 200 g white rice 24 mg, two slices of toast 14 mg.

And what about fruit? At 27 mg per 100 g, the banana is the most magnesium-rich everyday fruit, with one banana giving you around 32 mg. Avocado has 29 mg, raspberries 22 mg, dried figs 68 mg, and apples and oranges 5 to 10 mg. Cocoa is a different story: a heaped tablespoon is 50 mg, two espressos 48 mg, and filter coffee and tea almost nothing. You can try out how this adds up over a day right here.
Interactive

How do I get to 300 mg of magnesium a day?

Tap what you eat and drink on a typical day, and the bar shows where you land. Two days are preset. Values per portion according to USDA, with mineral water at 100 mg per litre as an example.

350 mg
0 mg von 350 mg

Nothing chosen yet. Tap some foods or load one of the two example days.

Values per portion according to USDA FoodData Central SR Legacy (grains, pulses and vegetables cooked; meat and fish cooked; nuts and seeds dry). Mineral water is just an example, so check the label for the actual content. DGE estimated values: 300 mg (women), 350 mg (men).

Mineral water as a source of magnesium

Water is the underrated source, and the only one with no calories. A mineral water can call itself magnesium-containing from 50 mg per litre. Many sit at 80 to 120 mg, and medicinal waters above 200 mg. The magnesium in it is absorbed well: in a study with labelled magnesium, absorption from a water with 110 mg per litre was 46%, and 52% when drunk with a meal. Half a litre raised blood levels just as much as a magnesium capsule. Tap water in Germany is usually under 20 mg per litre.
A magnesium-rich day on the kitchen worktop: porridge with banana and pumpkin seeds, wholemeal bread with hummus, lentils with spinach, almonds and cashews, dark chocolate, mineral water and avocado
Porridge with seeds, wholemeal bread, pulses, a handful of nuts and a piece of dark chocolate: that's all a 300 mg day needs.

What helps absorption and what slows it down

With a normal intake, your gut absorbs 30 to 50%, up to 80% when supply is tight, and only 20% with large single doses. Measurably helpful are small portions spread through the day, sourdough bread and soaked pulses, because fermentation breaks down the binding phytate, and steaming instead of boiling in lots of water, which costs you 30 to 40% of the minerals. Raw bran in large amounts, high-dose zinc, calcium or iron supplements at the same meal, and alcohol can all slow it down.

Magnesium in everyday life: drinkable meals and ready-made products

Heavily processed foods have a magnesium problem: when flour, rice and sugar are refined, the magnesium stays behind in the parts that are removed, and ready meals replace pulses and vegetables. With drinkable meals that have defined nutrient amounts, minerals are part of the recipe. Depending on the flavour, one bottle of Saturo delivers 87 to 135 mg of magnesium, 23 to 36% of the reference value of 375 mg. Cocoa is out in front because cocoa is rich in magnesium. It's no replacement for treatment if you have a confirmed deficiency, but it's a reliable contribution on days without porridge, lentils and nuts.
Ready-to-Drink 6 x 400 ml
From the Saturo range

Drinkable meal: a complete meal in a bottle

26 vitamins and minerals, including magnesium, potassium and calcium. Magnesium contributes to the reduction of tiredness and fatigue and to normal muscle function. Reference value for magnesium: 375 mg per day (NRV). For days when cooking isn't on the plan.

26Vitamins & minerals
36 gProtein
400kcal
135 mgMagnesium per bottle36% of the reference value
Choose a flavour
£3.79per meal
Drinkable meal · Cocoa£3.79 per meal ·
07 Special cases

Pregnancy, migraine, sport, over 60: who should take a closer look

Magnesium deficiency in pregnancy

The data is thinner than the routine with which magnesium gets recommended to pregnant women. The estimated value stays at 300 mg, because the body ramps up absorption; the DGE (German Nutrition Society) dropped its earlier recommendation of 310 mg in 2021. For calf cramps in pregnancy, the studies contradict each other. In cases of impending eclampsia, hospitals give magnesium sulphate as an infusion, which is emergency medicine and has nothing to do with tablets. A genuine deficiency mainly comes from persistent vomiting in the first few months; in that case it's measured and corrected. Otherwise: eat magnesium-rich foods, and only take a supplement after talking to your doctor, usually not more than 250 mg.

Headaches and migraine

The guideline of the German Neurological Society and the German Migraine and Headache Society (2025) lists magnesium for migraine prevention as an option with low evidence. The key study is German: 81 patients received 600 mg of trimagnesium dicitrate or a placebo for twelve weeks; attack frequency fell by 41.6 % versus 15.8 %, and 18.6 % got diarrhoea. This dose belongs in a doctor's hands and only works preventively, not during an attack. For tension headaches, there's no comparable data. The flickering in front of your eyes is the aura, not the mineral.

Sport, sweating and calf cramps

The calf cramp after a run sells most magnesium tablets, and it's almost never a magnesium deficiency. Sweat contains 1 to 10 mg per litre; even a summer half marathon costs 20 mg at most, and measurements in cyclists found no increased excretion via the kidneys either. In very intense training, sports doctors reckon on 10 to 20% extra need, which is a handful of nuts. The Cochrane review of eleven studies with 735 participants found no benefit for ordinary cramps; if you regularly get cramps after exercise, check your fluids, salt, increases in training load and stretching. What really counts after training is covered in the article Eating after exercise.
A female runner sits at the edge of a park path with a calf cramp, kneading her calf: cramps during sport usually have causes other than magnesium deficiency
The cramp while running: in eleven studies, magnesium didn't work better than placebo. Fluids, salt and how fast you increase your training load are the better levers.

From 60: medication, absorption, heart

With age, the causes pile up: the gut absorbs less, the kidneys lose more, appetite drops, and the medication list grows to include acid blockers, thiazides and laxatives. In the national consumption survey, one in three of those aged 65 to 80 was below the reference value, and among those taking thiazides, almost half of the older participants had a level that was too low. The same tablets are a common cause of sodium deficiency. The signs get put down to normal ageing: of 60 people with severe deficiency, almost half had an unsteady gait and a quarter had a tremor, most often caused by an acid blocker.

Effects of magnesium deficiency: what happens if it stays

A mild deficiency lasting a few weeks usually has no consequences once it's corrected. If it lasts longer or gets severe, four things are proven. Electrolytes: potassium and calcium drop too and can't be topped up while magnesium is missing. Heart: rhythm disorders, up to torsade de pointes. Nerves: tremor, unsteady gait, seizures. Metabolism: in cohort studies, diabetes risk fell by 14 % for every extra 100 mg of magnesium a day, but supplements only lowered blood pressure by 2 mmHg. Not proven: bone fractures, hair loss and weight gain.
08 Look it up

Frequently asked questions about magnesium deficiency

How can you tell if your body is low on magnesium?

In muscles and nerves: night-time calf cramps, muscle twitching (also in the eyelid), tingling in hands and feet, plus tiredness, loss of appetite, inner restlessness and heart palpitations. What matters is the combination over several weeks, together with a cause such as acid blockers, diuretics, alcohol, diarrhoea or diabetes. Only a blood test can tell you for sure.

What are the biggest magnesium drains?

Medication and losses, not stress: proton pump inhibitors for heartburn (risk up to 1.8-fold), diuretics, cisplatin and certain cancer antibodies, plus alcohol, persistent diarrhoea, bowel diseases and poorly controlled diabetes. Sweat contains only 1 to 10 mg per litre, and coffee costs a net of about 4 mg a day.

How long does it take to replenish your magnesium stores?

Serum levels rise within two to four weeks on a supplement; according to a 2021 review, the balance in bones and muscles only settles after 20 to 40 weeks.

What shouldn't you take together with magnesium?

Tetracycline and quinolone antibiotics, bisphosphonates and L-thyroxine: magnesium binds them in the gut and reduces their absorption, by 12 % for L-thyroxine in one study. The time gap is given in the patient information leaflet, usually several hours.

Is 400 mg of magnesium a day too much?

Not from food. As a supplement, it goes above the BfR maximum of 250 mg for food supplements, and from around 300 to 365 mg extra, some people get diarrhoea. When prescribed by a doctor, 300 to 600 mg is usual for a proven deficiency or for migraine prevention.

Can magnesium deficiency lead to weight gain?

Not directly. No human study shows that a magnesium deficiency makes you put on weight or that supplements help with losing it. What is proven is an indirect link via blood sugar regulation: in cohort studies, diabetes risk fell with higher intake. If you're gaining weight and feeling tired, get your blood sugar, thyroid and magnesium checked.

How does magnesium deficiency affect your hair?

None proven. There's no controlled study linking hair loss to magnesium deficiency, and magnesium isn't part of the usual hair loss work-up. If your hair is falling out, look at iron, thyroid, zinc and vitamin D, at medication, and at stressful periods three months earlier.

How much magnesium does a woman over 60 need per day?

300 mg, the same estimated value as for younger women; the DGE sees no increased requirement with age. Even so, the risk is highest from 60: the gut absorbs less, and acid blockers or thiazides often come into play. What makes sense: eat plenty of magnesium-rich foods and have it measured at your next blood test.

Sources · 70 sources anzeigen
  1. German Nutrition Society (DGE): Reference values for nutrient intake, magnesium. Estimated values for adequate intake, derivation 2021.
  2. German Nutrition Society (DGE): Selected questions and answers on magnesium. January 2022.
  3. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA): Scientific Opinion on Dietary Reference Values for magnesium. EFSA Journal 2015; 13(7): 4186.
  4. Regulation (EU) No 1169/2011 (Food Information Regulation), Annex XIII: Nutrient reference value for magnesium 375 mg.
  5. Commission Regulation (EU) No 432/2012: List of permitted health claims, magnesium.
  6. Max Rubner-Institut: National Consumption Study II, results report part 2. Karlsruhe 2008, chapter 5.7.4 Magnesium and tables A.49, A.65.
  7. Federal Institute for Risk Assessment (BfR): Proposed maximum levels for magnesium in foods, including food supplements. Opinion 2021, confirmed unchanged in 2024.
  8. Scientific Committee on Food (SCF) of the European Commission: Opinion on the Tolerable Upper Intake Level of Magnesium. 26 September 2001.
  9. Verbraucherzentrale (consumer advice centre): Magnesium, what do you need to watch out for? As of 18 February 2026.
  10. Mineral and Table Water Ordinance (Min/TafelWV), Annex 6: Claim “contains magnesium” from 50 mg/l.
  11. Jahnen-Dechent W., Ketteler M.: Magnesium basics. Clinical Kidney Journal 2012; 5(Suppl 1): i3–i14.
  12. Gröber U., Schmidt J., Kisters K.: Magnesium in Prevention and Therapy. Nutrients 2015; 7(9): 8199–8226.
  13. Costello R. B., Elin R. J., Rosanoff A. et al.: Perspective: The Case for an Evidence-Based Reference Interval for Serum Magnesium. Advances in Nutrition 2016; 7(6): 977–993.
  14. Workinger J. L., Doyle R. P., Bortz J.: Challenges in the Diagnosis of Magnesium Status. Nutrients 2018; 10(9): 1202.
  15. Fiorentini D., Cappadone C., Farruggia G., Prata C.: Magnesium: Biochemistry, Nutrition, Detection, and Social Impact of Diseases Linked to Its Deficiency. Nutrients 2021; 13(4): 1136.
  16. Ahmed F., Mohammed A.: Magnesium: The Forgotten Electrolyte. A Review on Hypomagnesemia. Medical Sciences 2019; 7(4): 56.
  17. Schimatschek H. F., Rempis R.: Prevalence of hypomagnesemia in an unselected German population of 16,000 individuals. Magnesium Research 2001; 14(4): 283–290.
  18. Wong E. T., Rude R. K., Singer F. R., Shaw S. T.: A high prevalence of hypomagnesemia and hypermagnesemia in hospitalized patients. American Journal of Clinical Pathology 1983; 79(3): 348–352.
  19. Chernow B., Bamberger S., Stoiko M. et al.: Hypomagnesemia in patients in postoperative intensive care. Chest 1989; 95(2): 391–397.
  20. Pham P. C., Pham P. M., Pham S. V., Miller J. M., Pham P. T.: Hypomagnesemia in patients with type 2 diabetes. Clinical Journal of the American Society of Nephrology 2007; 2(2): 366–373.
  21. Huang C.-L., Kuo E.: Mechanism of Hypokalemia in Magnesium Deficiency. Journal of the American Society of Nephrology 2007; 18(10): 2649–2652.
  22. Rude R. K., Oldham S. B., Singer F. R.: Functional hypoparathyroidism and parathyroid hormone end-organ resistance in human magnesium deficiency. Clinical Endocrinology 1976; 5(3): 209–224.
  23. Tzivoni D., Banai S., Schuger C. et al.: Treatment of torsade de pointes with magnesium sulfate. Circulation 1988; 77(2): 392–397.
  24. Khan A. M., Lubitz S. A., Sullivan L. M. et al.: Low serum magnesium and the development of atrial fibrillation in the community: the Framingham Heart Study. Circulation 2013; 127(1): 33–38.
  25. Ray S., Park K. W.: Movement Disorders and Other Neurologic Impairment Associated With Hypomagnesemia. Neurology: Clinical Practice 2023; 13(6): e200202.
  26. Tarleton E. K., Littenberg B., MacLean C. D., Kennedy A. G., Daley C.: Role of magnesium supplementation in the treatment of depression: A randomized clinical trial. PLoS One 2017; 12(6): e0180067.
  27. Mah J., Pitre T.: Oral magnesium supplementation for insomnia in older adults: a Systematic Review and Meta-Analysis. BMC Complementary Medicine and Therapies 2021; 21: 125.
  28. Pickering G., Mazur A., Trousselard M. et al.: Magnesium Status and Stress: The Vicious Circle Concept Revisited. Nutrients 2020; 12(12): 3672 (funded by Sanofi).
  29. U.S. Food and Drug Administration (FDA): Prescribing information for omeprazole, section 5.6 Hypomagnesemia, warning of May 2011.
  30. Park C. H., Kim E. H., Roh Y. H., Kim H. Y., Lee S. K.: The association between the use of proton pump inhibitors and the risk of hypomagnesemia: a systematic review and meta-analysis. PLoS One 2014; 9(11): e112558.
  31. Srinutta T., Chewcharat A., Takkavatakarn K. et al.: Proton pump inhibitors and hypomagnesemia: A meta-analysis of observational studies. Medicine 2019; 98(44): e17788.
  32. Gröber U.: Magnesium and Drugs. International Journal of Molecular Sciences 2019; 20(9): 2094.
  33. Cao Y., Liao C., Tan A. et al.: Meta-analysis of incidence and risk of hypomagnesemia with cetuximab for advanced cancer. Chemotherapy 2010; 56(6): 459–465.
  34. Rivlin R. S.: Magnesium deficiency and alcohol intake: mechanisms, clinical significance and possible relation to cancer development. Journal of the American College of Nutrition 1994; 13(5): 416–423.
  35. da Silva J. S. V., Seres D. S., Sabino K. et al.: ASPEN Consensus Recommendations for Refeeding Syndrome. Nutrition in Clinical Practice 2020; 35(2): 178–195.
  36. Blanchard A., Bockenhauer D., Bolignano D. et al.: Gitelman syndrome: consensus and guidance from a KDIGO Controversies Conference. Kidney International 2017; 91(1): 24–33.
  37. Montain S. J., Cheuvront S. N., Lukaski H. C.: Sweat mineral-element responses during 7 h of exercise-heat stress. International Journal of Sport Nutrition and Exercise Metabolism 2007; 17(6): 574–582.
  38. Baker L. B., Stofan J. R., Lukaski H. C., Horswill C. A.: Exercise-induced trace mineral element concentration in regional versus whole-body wash-down sweat. International Journal of Sport Nutrition and Exercise Metabolism 2011; 21(3): 233–239.
  39. Nielsen F. H., Lukaski H. C.: Update on the relationship between magnesium and exercise. Magnesium Research 2006; 19(3): 180–189.
  40. Zhang Y., Xun P., Wang R., Mao L., He K.: Can Magnesium Enhance Exercise Performance? Nutrients 2017; 9(9): 946.
  41. Kynast-Gales S. A., Massey L. K.: Effect of caffeine on circadian excretion of urinary calcium and magnesium. Journal of the American College of Nutrition 1994; 13(5): 467–472.
  42. Schuchardt J. P., Hahn A.: Intestinal Absorption and Factors Influencing Bioavailability of Magnesium: An Update. Current Nutrition and Food Science 2017; 13(4): 260–278.
  43. Fine K. D., Santa Ana C. A., Porter J. L., Fordtran J. S.: Intestinal absorption of magnesium from food and supplements. Journal of Clinical Investigation 1991; 88(2): 396–402.
  44. Bohn T., Davidsson L., Walczyk T., Hurrell R. F.: Phytic acid added to white-wheat bread inhibits fractional apparent magnesium absorption in humans. American Journal of Clinical Nutrition 2004; 79(3): 418–423.
  45. Bohn T., Davidsson L., Walczyk T., Hurrell R. F.: Fractional magnesium absorption is significantly lower in human subjects from a meal served with an oxalate-rich vegetable, spinach, as compared with a meal served with kale. British Journal of Nutrition 2004; 91(4): 601–606.
  46. Coudray C., Bellanger J., Castiglia-Delavaud C. et al.: Effect of soluble or partly soluble dietary fibres supplementation on absorption and balance of calcium, magnesium, iron and zinc in healthy young men. European Journal of Clinical Nutrition 1997; 51(6): 375–380.
  47. Kimura M., Itokawa Y.: Cooking losses of minerals in foods and its nutritional significance. Journal of Nutritional Science and Vitaminology 1990; 36 Suppl 1: S25–S32.
  48. Sabatier M., Arnaud M. J., Kastenmayer P., Rytz A., Barclay D. V.: Meal effect on magnesium bioavailability from mineral water in healthy women. American Journal of Clinical Nutrition 2002; 75(1): 65–71.
  49. Karagülle O., Kleczka T., Vidal C. et al.: Magnesium absorption from mineral waters of different magnesium content in healthy subjects. Forschende Komplementärmedizin 2006; 13(1): 9–14.
  50. Sobiecki J. G., Appleby P. N., Bradbury K. E., Key T. J.: High compliance with dietary recommendations in a cohort of meat eaters, fish eaters, vegetarians, and vegans: results from the EPIC-Oxford study. Nutrition Research 2016; 36(5): 464–477.
  51. Walker A. F., Marakis G., Christie S., Byng M.: Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnesium Research 2003; 16(3): 183–191.
  52. Lindberg J. S., Zobitz M. M., Poindexter J. R., Pak C. Y. C.: Magnesium bioavailability from magnesium citrate and magnesium oxide. Journal of the American College of Nutrition 1990; 9(1): 48–55.
  53. Firoz M., Graber M.: Bioavailability of US commercial magnesium preparations. Magnesium Research 2001; 14(4): 257–262.
  54. Pouteau E., Kabir-Ahmadi M., Noah L. et al.: Superiority of magnesium and vitamin B6 over magnesium alone on severe stress in healthy adults with low magnesemia: A randomized, single-blind clinical trial. PLoS One 2018; 13(12): e0208454.
  55. Attinger M. C., von Felten S., Rodrigues C. L. et al.: Drug-Drug Interactions of Levothyroxine/Magnesium-Citrate and Levothyroxine/Magnesium-Aspartate in Healthy Subjects (ThyroMag). Clinical and Translational Science 2025; 18(11): e70409.
  56. Zhang X., Li Y., Del Gobbo L. C. et al.: Effects of Magnesium Supplementation on Blood Pressure: A Meta-Analysis of Randomized Double-Blind Placebo-Controlled Trials. Hypertension 2016; 68(2): 324–333.
  57. Garrison S. R., Korownyk C. S., Kolber M. R. et al.: Magnesium for skeletal muscle cramps. Cochrane Database of Systematic Reviews 2020; 9: CD009402.
  58. Diener H.-C., Förderreuther S., Kropp P. et al.: Treatment of migraine attacks and migraine prophylaxis. S1 guideline of the DGN and DMKG, AWMF 030/057, version 7.1, 8 August 2025.
  59. Peikert A., Wilimzig C., Köhne-Volland R.: Prophylaxis of migraine with oral magnesium: results from a prospective, multi-center, placebo-controlled and double-blind randomized study. Cephalalgia 1996; 16(4): 257–263.
  60. Chiu H.-Y., Yeh T.-H., Huang Y.-C., Chen P.-Y.: Effects of Intravenous and Oral Magnesium on Reducing Migraine: A Meta-analysis of Randomized Controlled Trials. Pain Physician 2016; 19(1): E97–E112.
  61. Dong J.-Y., Xun P., He K., Qin L.-Q.: Magnesium intake and risk of type 2 diabetes: meta-analysis of prospective cohort studies. Diabetes Care 2011; 34(9): 2116–2122.
  62. Simental-Mendía L. E., Sahebkar A., Rodríguez-Morán M., Guerrero-Romero F.: A systematic review and meta-analysis of randomized controlled trials on the effects of magnesium supplementation on insulin sensitivity and glucose control. Pharmacological Research 2016; 111: 272–282.
  63. Makrides M., Crosby D. D., Bain E., Crowther C. A.: Magnesium supplementation in pregnancy. Cochrane Database of Systematic Reviews 2014; 4: CD000937.
  64. Farsinejad-Marj M., Saneei P., Esmaillzadeh A.: Dietary magnesium intake, bone mineral density and risk of fracture: a systematic review and meta-analysis. Osteoporosis International 2016; 27(4): 1389–1399.
  65. Moslehi M., Arab A., Shadnoush M., Hajianfar H.: The Association Between Serum Magnesium and Premenstrual Syndrome: a Systematic Review and Meta-Analysis of Observational Studies. Biological Trace Element Research 2019; 192(2): 145–152.
  66. Barbagallo M., Veronese N., Dominguez L. J.: Magnesium in Aging, Health and Diseases. Nutrients 2021; 13(2): 463.
  67. U.S. Department of Agriculture, Agricultural Research Service: FoodData Central, SR Legacy Release (2018). Magnesium content per 100 g.
  68. AWMF S3 guideline: Screening, diagnosis and treatment of alcohol-related disorders. Register 076-001, short version, validity extended 01/2025.
  69. American Diabetes Association: Standards of Care in Diabetes 2026, Section 5 (chromium not recommended). Diabetes Care 2026; 49(Suppl 1): S89–S131.
  70. Barber J., McKeever T. M., McDowell S. E. et al.: A systematic review and meta-analysis of thiazide-induced hyponatraemia: time to reconsider electrolyte monitoring regimens after thiazide initiation? British Journal of Clinical Pharmacology 2015; 79(4): 566–577.
Gregor Aßlaber
Gregor AßlaberAuthor · Editor, Saturo

Has been writing for Saturo since 2019 about nutrition, nutrients and how to get good nutrition in everyday life in practice.

Joerg Hauke
Joerg HaukeFachliche Prüfung · Nutrition expert

Hat diesen Artikel am 23. September 2026 auf fachliche Richtigkeit geprüft. This content is not a substitute for medical advice.

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