Magnesium is a common mineral your body needs to work well. You get it from foods, some fortified products, supplements, and medicines like antacids and some laxatives.

 

What magnesium does

Magnesium helps hundreds of processes in the body. It:

• Helps your muscles and nerves work properly  
• Supports energy production and keeps cells running  
• Plays a role in blood sugar and blood pressure control  
• Helps build strong bones and makes DNA and important antioxidants  
• Helps move calcium and potassium in and out of cells — important for heartbeats and muscle contractions

 

How much you have and how it’s measured

– An adult has about 25 grams of magnesium in the body — mostly in bones and tissues.  

– Only a tiny amount is in the blood, so blood tests don’t always show the full picture. Doctors may use tests plus symptoms to check status.

 

Where magnesium comes from

– Best food sources: leafy greens, nuts and seeds, beans and lentils, whole grains, and some fish.  

– Supplements: come in different forms; some are absorbed better (citrate, glycinate, malate) while others are less well absorbed (oxide).  

– Medicines: found in some antacids and laxatives.

 

How much you need

Adults generally need about 310–420 mg a day depending on age and sex. Kids and infants need different amounts.

 

Signs of too little magnesium

Early signs: poor appetite, nausea, tiredness, weakness.  

If it gets worse: muscle cramps, numbness, seizures, and irregular heart rhythms. Serious deficiency is uncommon in healthy people.

 

Who’s more likely to be low

People at higher risk: older adults, people with digestive diseases, people with type 2 diabetes, heavy drinkers, and those on certain medications (like some diuretics or long-term stomach acid medicines).

 

Health links 

• Heart and blood pressure: higher magnesium intake is linked to small benefits; supplements only lower blood pressure a little in studies.  
• Type 2 diabetes: people who eat more magnesium seem to have lower diabetes risk, but evidence that supplements help blood sugar control is mixed.  
• Bone health: magnesium is important for bones, but we don’t have clear proof that supplements prevent osteoporosis.  
• Migraines: low magnesium is linked to migraines, and supplements can help prevent them for some people.

 

Safety and side effects

• From food: too much is unlikely for healthy people.  
• From supplements: high doses can cause diarrhea, nausea, and cramps. Very large doses can be dangerous (low blood pressure, breathing problems, irregular heartbeat).  
• The usual upper limit for supplements is about 350 mg/day for adults unless a doctor recommends otherwise.

 

Drug interactions and precautions

• Magnesium can reduce absorption of some medicines (certain antibiotics, bisphosphonates). Take those drugs a few hours apart from magnesium.  
• Some drugs (diuretics, proton-pump inhibitors) can lower magnesium levels.  
• People with kidney problems should only take magnesium under medical supervision.

 

Simple advice

• Try to get magnesium from a balanced diet first.  
• Consider a supplement if your diet is low or you’re in a higher-risk group — and check with your healthcare provider if you have health issues, take medicines, or have kidney disease.  
• If you try supplements, pick well-absorbed forms (like glycinate or citrate) and start with a moderate dose to avoid stomach upset.