In short: Magnesium's benefits cover energy, muscles, nerves, bones and teeth: it's a mineral your body needs every day. In the EU, ten effects are officially confirmed, for example: Magnesium contributes to a reduction of tiredness and fatigue. Magnesium contributes to normal muscle function. Good sources are seeds, nuts, wholegrains and pulses. Adults need around 300 to 350 mg a day.
Key points
- Ten official effects: from energy metabolism and muscle function to nerves and mental function, right through to bones, teeth and cell division.
- Involved in every cell: magnesium takes part in over 600 reactions in the body, above all anything that needs energy.
- Easy to reach through food: pumpkin seeds, almonds, oats and wholemeal bread all provide plenty.
- Some people need more: for example if you do a lot of sport, are older, or take certain medicines long-term.
- Patience pays off: magnesium is absorbed within hours, but your blood level settles into a new balance over several months.
Contents
- What is magnesium?
- How magnesium works in your body
- Energy and less tiredness
- Muscles, exercise and electrolytes
- Nerves and mental function
- Bones and teeth
- Protein synthesis and cell division
- How fast does magnesium work?
- Which foods are high in magnesium?
- How much magnesium do you need, and who needs more?
- How do you know if you're low on magnesium?
- Blood pressure, migraine and more: what has been studied?
- All our magnesium articles at a glance
- Our takeaway
- Frequently asked questions
- Limits of the research and all sources
What is magnesium?
Magnesium is a mineral. Your body can't make it itself, so you take it in through food and drink. An adult carries around 25 g of magnesium. About half of it sits in the bones, the rest mainly in muscles and other tissue.1 Less than 1% is found in the blood.2
Inside your cells, magnesium is the second most common positively charged particle after potassium. There, it takes part in over 600 reactions controlled by enzymes.3 That's why practically every organ needs magnesium, especially the brain, heart and muscles.3
How magnesium works in your body
Magnesium is involved in energy, muscles, nerves, bones and building new cells. For these tasks, the EU has officially approved ten statements.4 They're considered scientifically established. Here they are in exact wording, alongside what's behind them:
| Officially approved statement | What's behind it in your body |
|---|---|
| Magnesium contributes to normal energy-yielding metabolism. | The energy carrier ATP is bound to magnesium inside the cell. |
| Magnesium contributes to a reduction of tiredness and fatigue. | Follows from its role in energy metabolism. |
| Magnesium contributes to normal muscle function. | Magnesium is calcium's counterpart in tensing and relaxing muscles. |
| Magnesium contributes to electrolyte balance. | The sodium-potassium pump in every cell needs magnesium. |
| Magnesium contributes to normal functioning of the nervous system. | Magnesium dampens the excitability of nerve cells. |
| Magnesium contributes to normal psychological function. | Linked to its role in the nervous system. |
| Magnesium contributes to normal protein synthesis. | The cell's protein factories (ribosomes) need magnesium. |
| Magnesium has a role in the process of cell division. | Magnesium is involved in copying genetic information. |
| Magnesium contributes to the maintenance of normal bones. | Half the body's magnesium is built into bone. |
| Magnesium contributes to the maintenance of normal teeth. | Teeth are built from minerals, just like bone. |
Explanations based on physiology reviews.1, 3
The sections below go through each area individually. Under each one, you'll find what studies show in addition.
Energy and less tiredness
Magnesium contributes to normal energy-yielding metabolism. Magnesium contributes to a reduction of tiredness and fatigue. The two go together: every cell gets its energy from ATP, and inside the cell ATP is almost always bound to magnesium. Without magnesium, the cell can barely use that energy.3
For everyday life, that means: if you often feel worn out, it's worth taking a look at what you eat. Wholegrains, nuts and pulses provide magnesium and slow-release energy at the same time.
What the studies show: The cell's energy supply depends on magnesium, and review studies agree on this.3, 5 If you eat too little magnesium over a long period, that changes biochemical processes in your body, even while your blood level still looks normal.5
Muscles, exercise and electrolytes
Magnesium contributes to normal muscle function. Magnesium contributes to electrolyte balance. When a muscle tenses, calcium flows into the muscle cell; when it relaxes, magnesium helps as the counterpart. Electrolytes are salts like sodium and potassium that carry nerve and muscle signals. The pump that keeps them balanced inside the cell needs magnesium.3
If you train a lot, you lose more magnesium and probably need somewhat more of it.6 If you're short on it, that can hold back performance.7
What the studies show: A meta-analysis compared 855 athletes with 521 untrained people. The athletes ate more magnesium but also excreted more and had somewhat lower blood levels.6 A systematic review on muscle soreness found less soreness and better recovery with magnesium in four studies. It estimates that intensive training raises magnesium needs by 10 to 20%.7 An analysis of 14 controlled studies saw the clearest benefits for muscle strength in older people and in people with heavy alcohol use. Both groups often only just get enough.8
Our take: Magnesium makes the most sense for people who train hard or who are older, because both groups need more or often only just get enough. Focus on magnesium-rich food first. If that's not enough, a supplement with up to 250 mg a day is a sensible addition. More on the sport angle is in When should you take magnesium? The article on magnesium citrate explains why this form is popular with athletes and how to take it comfortably.
Nerves and mental function
Magnesium contributes to normal functioning of the nervous system. Magnesium contributes to normal psychological function. In nerve cells, magnesium acts like a brake: it sits inside an important signalling channel (the NMDA receptor) and stops nerve cells from becoming too easily excited.3
That's why many people take magnesium in the evening, as part of their wind-down routine.
What the studies show: A systematic review of 18 studies found signs of less anxiety in people prone to it. Among mildly anxious people, four of eight studies showed a benefit; for premenstrual complaints, four of seven did.9 A more recent review of 15 studies saw improvements in five of seven anxiety studies and five of eight sleep studies.10 In a study of 155 adults, sleep problems improved more with 250 mg of magnesium as bisglycinate than with a placebo.11 In older people with sleep problems, those taking magnesium fell asleep around 17 minutes faster on average.12
Everything on sleep is in Magnesium and sleep. Which form suits the evening particularly well is explained in Magnesium glycinate: benefits and side effects. How magnesium interacts with the amino acid tryptophan is covered in L-tryptophan and magnesium. And why a special form was developed specifically for the brain is shown in Magnesium L-threonate.
Bones and teeth
Magnesium contributes to the maintenance of normal bones. Magnesium contributes to the maintenance of normal teeth. Bones are the body's largest magnesium store. Part of it sits on the bone surface and can be released into the blood when needed, which is how your blood level stays stable.1
Good for bones is a combination: enough magnesium, calcium, vitamin D, protein and exercise.
What the studies show: A large US study followed 73,684 postmenopausal women. Those with the highest magnesium intake had 3% higher hip bone density than the women with the lowest intake.13 An analysis of studies in people aged 60 and over also found: more magnesium went hand in hand with higher hip bone density.14
Protein synthesis and cell division
Magnesium contributes to normal protein synthesis. Magnesium has a role in the process of cell division. Every time your body builds muscle, renews skin or forms blood cells, it needs these two steps. The ribosomes that assemble proteins only hold their shape with magnesium. The enzymes that copy genetic information when a cell divides also work with magnesium.3
That's another reason why athletes and people in phases of growth or muscle building should pay attention to a good supply.
How fast does magnesium work?
Magnesium is absorbed within hours of taking it. With regular intake, it takes several months for your blood magnesium to settle at a new level. Most studies ran for four weeks to three months. So plan for at least four to eight weeks before you judge the results.
What the studies show: An analysis of 48 studies shows that the blood level is stable after around 20 weeks of daily intake.15 The bisglycinate sleep study ran for four weeks.11
Where and how fast magnesium reaches the gut is explained in Which magnesium is best absorbed? You'll find the right time of day in When should you take magnesium?
Which foods are high in magnesium?
Seeds, nuts, cocoa, wholegrains, pulses and leafy greens provide plenty of magnesium. Fruit tends to provide little.
| Food (per 100 g) | Magnesium |
|---|---|
| Pumpkin seeds, dried | 592 mg |
| Sunflower seeds | 325 mg |
| Cashew nuts | 292 mg |
| Almonds | 270 mg |
| Dark chocolate (70 to 85% cocoa) | 228 mg |
| Rolled oats | 138 mg |
| Spinach, raw | 79 mg |
| Wholemeal bread (wheat) | 75 mg |
| Chickpeas, cooked | 48 mg |
| Banana | 27 mg |
Source: USDA FoodData Central, "SR Legacy" dataset.16
Tip: A handful of pumpkin seeds (30 g) brings around 178 mg of magnesium, roughly half a woman's daily needs (our calculation). Sprinkle them over porridge, salad or soup. Add 50 g of rolled oats (69 mg) and two slices of wholemeal bread (75 mg) and you're already past 300 mg (our calculation).
More foods and a full example day are in How much magnesium is in food?
How much magnesium do you need, and who needs more?
Adult women need around 300 mg of magnesium a day, men around 350 mg. That also applies during pregnancy and breastfeeding.17, 18 Most people in Germany reach these levels, but not everyone: in Germany's National Nutrition Survey, 26% of men and 29% of women fell short.19
For supplements, European authorities recommend no more than 250 mg a day on top of food.20 Magnesium from food doesn't count towards that limit.
Your supply deserves more attention if any of these apply to you:
- A lot of exercise: with intensive training, needs are probably 10 to 20% higher.7
- Older age: older people often eat less magnesium, absorb it less well and lose more of it through the kidneys.21
- Certain medicines: stomach-acid reducers (proton pump inhibitors) and diuretics (water tablets) can cost you magnesium.22
- Heavy alcohol use or type 2 diabetes: both are common causes of low magnesium levels.22
All reference values by age and sex are in How much magnesium per day? What happens with too much, and why the 250 mg limit applies, is explained in Too much magnesium.
How do you know if you're low on magnesium?
A mild deficiency usually barely shows, and if it does, the symptoms can have many other causes. The most reliable check is a look at your diet: if you rarely eat wholegrains, nuts, seeds or pulses, you're probably below your needs.
What the studies show: Mild deficits often cause no clear signs. What's described tends to be general complaints such as exhaustion, sleep problems and irritability, which in older people are easily mistaken for ageing.21 With a pronounced deficiency, review articles list muscle cramps, exhaustion, seizures and heart rhythm disturbances.23 A normal blood magnesium level doesn't reliably rule out a tight supply, because the body keeps the blood level stable using its stores.5
Important: These complaints aren't a self-test. Get persistent muscle cramps, palpitations or ongoing exhaustion checked by your GP rather than taking high doses on a hunch. Talk to your GP before taking magnesium if you have kidney disease, because magnesium can then build up in your blood.24 Leave a few hours' gap from thyroid hormone medication, certain antibiotics and osteoporosis medicines. The details are in What shouldn't you take together with magnesium?
Blood pressure, migraine and more: what has been studied?
Many people search for magnesium in connection with illnesses. The research here is extensive. We describe briefly and neutrally what has been studied. A supplement doesn't replace treatment, and if you have a medical condition, discuss magnesium with your doctor.
- Blood pressure: An analysis of 34 controlled studies with 2,028 participants found blood pressure around 2 mmHg lower than with placebo. Participants took an average of 368 mg of magnesium a day over three months.25 A more recent analysis saw the biggest differences in people with high blood pressure and low magnesium levels.26
- Migraine: In a study of 81 people with migraine, the number of attacks fell by 42% with 600 mg of magnesium a day, versus 16% with placebo.27 This amount is well above the supplement upper limit and belongs under medical supervision. A large overview of meta-analyses rated the evidence for migraine as strong.28
- Type 2 diabetes: In observational studies, people with more magnesium in their diet developed type 2 diabetes less often.28 Studies like this show an association, not proof of cause and effect.
All our magnesium articles at a glance
This article is the starting point. If you want to go deeper, here are all the magnesium questions we've answered in detail so far:
- When should you take magnesium? Morning or evening, before or after food, split doses or not. With a simple intake plan and the key gaps to leave from medicines.
- How much magnesium per day? Daily needs by age and sex, extra needs, and an example calculation for your day.
- Too much magnesium When it becomes too much, what helps with diarrhoea, and who should be cautious.
- Which magnesium is best? Every form from oxide to bisglycinate in one table, and which form suits which goal.
- Which magnesium is best absorbed? How magnesium crosses the gut wall and what helps or slows absorption.
- Magnesium glycinate and bisglycinate The stomach-friendly form for the evening, with the sleep study and an authenticity check for supplements.
- Magnesium citrate and trimagnesium dicitrate Highly soluble and well absorbed. Also explains why citrate has a laxative effect for some people.
- Magnesium L-threonate The form developed for the brain. What studies show on memory and sleep.
- Magnesium and sleep Which form, how much and when, and what the combination with melatonin does.
- L-tryptophan and magnesium Why the two work well together and when to be careful with medicines.
How to do it:
- Food first: work through a normal day using the table above. Often one extra handful of seeds is enough.
- Then supplement: if you don't get there, take up to 250 mg of magnesium a day, ideally with a meal.
- Choose a well-absorbed form: citrate or bisglycinate, for example.
- Stick with it: take magnesium daily and give it at least four to eight weeks.
Our takeaway
Magnesium is one of the minerals with the most jobs to do in your body. It's in every cell, keeps your energy supply running, and is needed for muscles, nerves, bones and teeth. The EU officially confirms ten effects. With seeds, nuts, wholegrains and pulses, you cover a good part of your needs. If you train a lot, are older, or take medicines that cost you magnesium, you benefit especially from a deliberate supply. A supplement with up to 250 mg a day is then a simple addition.
Frequently asked questions
What is magnesium good for?
For energy, muscles, nerves, mental function, bones, teeth, protein synthesis and cell division. Magnesium contributes to normal functioning of the nervous system. Magnesium contributes to the maintenance of normal bones. All ten official statements are in the table above.4
What does magnesium do for the body?
It takes part in over 600 reactions, above all everything that uses energy from ATP.3 It also dampens the excitability of nerve and muscle cells and is a building block of bone.1, 3
Should I take magnesium every day?
If you don't reach around 300 mg (women) or 350 mg (men) through food, yes.17 Up to 250 mg a day from supplements is considered safe for healthy adults, even long-term.20 With kidney disease, only after checking with your GP.24
Is it better to take magnesium in the morning or at night?
Either works. What matters more is taking it regularly with a meal. Many people choose the evening because there are positive sleep studies.11, 12 All the details are in When should you take magnesium?
What is a magnesium complex?
A supplement that mixes several magnesium forms, for example citrate, bisglycinate and oxide. How much of it you absorb depends on the share of each form. More on this in Magnesium complex: is a mix better?
What side effects does magnesium have?
The most common is loose stools, especially with larger amounts taken at once.20 If you split larger amounts across two meals, most people tolerate magnesium well. More on this in Too much magnesium.
Limits of the research and all sources
The ten official statements are considered established. For the additional study findings, there are open questions. The muscle-soreness review relies on just four small studies.7 In trained athletes with a good supply, the analysis of 14 studies found no strength gain.8 In a small study of 15 trained people, some endurance values were even slightly worse with 300 mg of magnesium chloride twice a day.29 For night-time calf cramps in older people, magnesium was not noticeably better than placebo according to a Cochrane review; results for cramps in pregnancy are contradictory.30
The studies on anxiety and stress are mostly small and methodologically weak, as the authors themselves note.9, 10 In the bisglycinate sleep study, the additional effect over placebo was small.11 The bone findings come from observational studies: higher bone density there wasn't linked to fewer fractures.13, 14 The blood pressure studies varied a lot, and in people with normal blood pressure the effect wasn't reliably shown.26 The migraine study used a high amount, at which 19% got diarrhoea.27 A simple, reliable test for magnesium status doesn't exist yet.5
Show all 30 sources
| # | Study | Who was studied | Result | Strength of evidence |
|---|---|---|---|---|
| 1 | Rude 1998, J Bone Miner Res | Review | around 25 g of magnesium in the body, about half in bone, part of it exchangeable | Review |
| 2 | Elin 1994, Am J Clin Pathol | Review | less than 1% of the body's magnesium is in the blood | Review |
| 3 | de Baaij et al. 2015, Physiol Rev | Review | over 600 enzyme reactions, mainly energy metabolism and protein synthesis; important for brain, heart, muscles | comprehensive review |
| 4 | Regulation (EU) No 432/2012 | Legal act | list of approved health claims, including 10 for magnesium | legal basis |
| 5 | Fiorentini et al. 2021, Nutrients | Review | blood level doesn't reliably reflect body stores; Western diets often low in magnesium | Review |
| 6 | Zhang et al. 2023, Food Sci Hum Wellness | 14 studies, 855 athletes, 521 untrained | higher intake, but lower blood level and more excretion | meta-analysis of cross-sectional studies |
| 7 | Tarsitano et al. 2024, J Transl Med | 4 studies with physically active people | less muscle soreness, better recovery; needs estimated 10 to 20% higher | systematic review with 4 studies, publicly funded |
| 8 | Wang et al. 2017, Magnes Res | 14 controlled studies, 542 people | benefits mainly in older people and people with alcohol problems, not athletes | meta-analysis |
| 9 | Boyle et al. 2017, Nutrients | 18 studies with susceptible groups | 4 of 8 (mildly anxious) and 4 of 7 (PMS) showed less anxiety | systematic review, study quality rated weak by the authors; one author on a manufacturer's advisory board |
| 10 | Rawji et al. 2024, Cureus | 15 studies | 5 of 7 anxiety studies and 5 of 8 sleep studies showed improvement | systematic review, small and inconsistent studies |
| 11 | Schuster et al. 2025, Nat Sci Sleep | 155 adults, 250 mg magnesium as bisglycinate, 4 weeks | sleep problems improved more than with placebo (small effect) | controlled study |
| 12 | Mah & Pitre 2021, BMC Complement Med Ther | 3 studies, 151 older people | fell asleep around 17 minutes faster | meta-analysis, low evidence |
| 13 | Orchard et al. 2014, Am J Clin Nutr | 73,684 postmenopausal women (USA) | hip bone density 3% higher with high magnesium intake; fractures not less frequent | large observational study |
| 14 | Groenendijk et al. 2022, Bone | 12 studies with people aged 60+ | more magnesium, higher hip bone density; no link with fractures | systematic review of observational studies |
| 15 | Zhang et al. 2016, J Nutr | 48 studies, 2,131 people | blood level stable after around 20 weeks | meta-analysis |
| 16 | USDA FoodData Central, SR Legacy | Nutrient database | magnesium content of the food table | reference data |
| 17 | EFSA NDA Panel 2015, EFSA Journal | Dietary surveys from 9 EU countries | men 350 mg, women 300 mg; pregnant and breastfeeding women as other women | official assessment |
| 18 | DGE, ÖGE, SGE 2021: Reference values for magnesium | Reference values | men 350 mg, women 300 mg | official reference values |
| 19 | Max Rubner Institute 2008: National Nutrition Survey II, Part 2 | 15,371 respondents (aged 14 to 80) | 26% of men and 29% of women below the reference value | nationwide German survey |
| 20 | SCF 2001 / EFSA 2006: Tolerable Upper Intake Levels | Regulatory assessment | upper limit 250 mg/day from supplements; loose stools as the main side effect | official assessment |
| 21 | Barbagallo et al. 2021, Nutrients | Review | lower intake, poorer absorption, more loss in older age; mild deficits often without clear signs | Review |
| 22 | Kröse & de Baaij 2024, Nephrol Dial Transplant | Review | common causes of low levels: alcohol, type 2 diabetes, stomach-acid and water medicines | Review |
| 23 | Bosman et al. 2021, Proc Nutr Soc | Review | pronounced deficiency: muscle cramps, exhaustion, seizures, heart rhythm disturbances | Review |
| 24 | Rosner et al. 2023, Mayo Clin Proc | Review | too much magnesium in the blood mainly with reduced kidney function | Review |
| 25 | Zhang et al. 2016, Hypertension | 34 studies, 2,028 people, average 368 mg, 3 months | blood pressure around 2 mmHg lower than with placebo | meta-analysis of double-blind studies; one co-author from a magnesium research association |
| 26 | Argeros et al. 2025, Hypertension | 38 studies, 2,709 people | bigger reduction with high blood pressure and low magnesium; not significant with normal blood pressure | meta-analysis, very inconsistent studies |
| 27 | Peikert et al. 1996, Cephalalgia | 81 people with migraine, 600 mg trimagnesium dicitrate, 12 weeks | attacks -42% versus -16% with placebo; 19% diarrhoea | controlled study |
| 28 | Veronese et al. 2020, Eur J Nutr | 16 meta-analyses, 55 endpoints | strong evidence for migraine; type 2 diabetes only from observational studies | overview of meta-analyses, publicly funded |
| 29 | Bomar et al. 2025, Nutrients | 15 trained people, 2 × 300 mg magnesium chloride, 9 days | endurance values slightly worse than with placebo | small controlled study |
| 30 | Garrison et al. 2020, Cochrane Database Syst Rev | 11 studies, 735 people | night-time calf cramps in older people: no noticeable benefit; pregnancy contradictory | Cochrane review |
Author: PRONESIUM Editorial Team · Last reviewed: 29/09/2026 · This article does not replace medical advice.
