How Long Does Magnesium Stay in Your Body?

author avatar Dr. Eric Berg 08/31/2023

Magnesium is an essential mineral needed for energy production, blood sugar control, blood pressure regulation, and maintaining healthy muscle and nerve function.

Many people struggle to meet their recommended daily magnesium intake, and conditions including insulin resistance, diabetes, and kidney disease may cause excess magnesium excretion, which can deplete magnesium levels within 24 hours. 

Recognize the signs of magnesium deficiency and learn how the right diet and dietary supplements can help you get enough magnesium.

Magnesium supplement

What is magnesium?

Magnesium is needed for more than 600 biochemical pathways and cellular functions. 

It’s the fourth most abundant mineral in the human body, and most magnesium is stored in bones and muscles. 

Only around one percent of magnesium is found circulating in the blood, which explains why it can be challenging to accurately measure magnesium levels and diagnose potential magnesium deficiency with standard blood tests.

Unfortunately, most people don’t consume enough dietary magnesium to maintain healthy levels, greatly increasing the risk of becoming magnesium deficient.   

Research published in Open Heart found that “Approximately 50% of Americans consume less than the Estimated Average Requirement (EAR) for magnesium, and some age groups consume substantially less.”      

Watch the video below to learn how long magnesium stays in the body.

What does magnesium do for your body?

Magnesium plays a crucial role in maintaining a wide range of physiological functions. 

Here are some key roles of magnesium:

  • DNA and protein synthesis

  • Energy production

  • Muscle function

  • Nerve impulse transmission 

  • Blood sugar control  

  • Blood pressure regulation 

  • Bone health 

  • Brain function 

Magnesium’s health benefits have been extensively researched. According to a review study published in Scientifica, magnesium has been found effective in the management and prevention of numerous health issues.

Here are several health conditions that may benefit from magnesium supplementation:

  • Migraines

  • Metabolic syndrome 

  • Diabetes

  • Hyperlipidemia 

  • Asthma

  • Premenstrual syndrome 

  • Cardiac arrhythmia 

  • Depression  

Magnesium status questionnaire

How long does magnesium stay in your body?

How long magnesium stays in the body depends on various factors, including your individual metabolism, kidney function, and dietary habits. 

Compared to other nutrients, magnesium isn’t stored in the body for long periods. 

“It’s estimated that magnesium remains in the body for around 40 hours in healthy individuals,” explains Dr. Berg. “However, a high-carb diet, kidney issues, and blood sugar imbalances can increase the rate of magnesium excretion and deplete a significant amount of body stores within 12 to 24 hours.” 

The kidneys play a crucial role in regulating the reabsorption and excretion of magnesium, and individuals with poor kidney function tend to excrete more magnesium, leaving them at risk of deficiency.

Unfortunately, many individuals are unaware of impaired kidney function and the potential impact on their magnesium levels.  

According to the Centers for Disease Control and Prevention (CDC), 14 percent of US adults suffer from chronic kidney disease, and many of those affected are unaware they have it. 

Genetic predisposition, high blood pressure, obesity, diabetes, insulin resistance, and metabolic syndrome are primary risk factors for chronic kidney disease.

In addition, your dietary habits can significantly impact magnesium levels.

Regularly consuming too many carbs and sugars cause spikes in blood sugar and insulin levels which stimulates the kidneys to excrete magnesium. This explains why individuals with diabetes and pre-diabetes are at such a high risk of magnesium deficiency.

Dietary phytates—natural compounds classified as anti-nutrients—are found in grains and legumes. Phytates can bind to minerals such as magnesium, which inhibits intestinal magnesium absorption and can cause or exacerbate deficiency.  

Magnesium deficiency illustration

Signs of low magnesium

Because magnesium plays such a vital role in a wide range of cellular processes, magnesium deficiency can manifest through various signs and symptoms.

While muscle cramps, fatigue, and low exercise tolerance are typically the first sign of magnesium deficiency, there are many other symptoms, such as:

  • Heart palpitations and arrhythmia

  • Insomnia or other sleep problems

  • High blood pressure 

  • Muscle stiffness

  • Weak bones

  • Mood swings 

  • Chocolate cravings 

  • Loss of appetite

  • Pins and needles 

  • Constipation 

Side effects of too much magnesium

Magnesium toxicity is rare and almost never linked to dietary magnesium intake. 

However, taking large doses of magnesium supplements can lead to side effects, including:

  • Nausea and vomiting

  • Low blood pressure

  • Confusion 

  • Drowsiness

  • Abdominal pain

  • Diarrhea 

Magnesium supplementation can interact with certain medications, such as diuretics, antibiotics, and calcium channel blockers, and has been found to interfere with the effectiveness of drugs used to treat osteoporosis.

It’s important to discuss magnesium supplements with a healthcare provider if you are taking prescription medications, suffer from kidney problems, or have a low heart rate.   

Nuts and seeds

Best sources of magnesium

Magnesium is found in many foods, and regularly eating magnesium-rich foods supports your well-being and promotes healthy magnesium levels.

Here are some of the best dietary sources of magnesium:

  • Leafy green vegetables such as spinach, kale, Swiss chard, and mustard greens 

  • Seeds and nuts

  • Avocado

  • Dark chocolate 

  • Tofu

  • Dairy products 

  • Oily fish 

Calcium and magnesium supplements are amongst the most popular dietary supplements and are widely available. However, it’s important to understand that there are various elemental forms of magnesium that differ in effectiveness, bioavailability, and risk of side effects. 

Magnesium chloride is generally well absorbed and a commonly used elemental form of magnesium that can help prevent magnesium deficiency.

Magnesium citrate and magnesium glycinate are also well absorbed and may be effective in treating constipation, headaches, muscle cramps, and sleep issues. 


Magnesium malate doesn’t have a laxative effect and has been found beneficial in individuals with fibromyalgia and chronic fatigue syndrome.  

Some cheaper supplements contain magnesium hydroxide, which interferes with iron and folic acid absorption and should be avoided. 

Woman checking supplement label

How much magnesium can you take each day?


The recommended dietary allowance (RDA) for daily magnesium intake is between 310 and 360 mg for adult women and ranges from 400 to 420 mg for adult men. 

However, the RDA is only based on preventing magnesium deficiency and doesn't consider an individual's health status, metabolism, and body size. It may require between 500 to 600 mg of magnesium per day to achieve and maintain healthy magnesium levels.  

Magnesium-rich foods

Key takeaways

Magnesium plays a vital role in health and is required for more than 600 cellular processes and metabolic pathways.

Magnesium doesn’t remain in the body for long and is typically excreted via the kidneys within 40 hours. However, poor kidney function and a high-carb diet can significantly accelerate magnesium loss, leaving many at risk of inadequate magnesium levels.   

Increasing magnesium-rich foods and taking a magnesium supplement can promote healthy magnesium status and prevent deficiency symptoms, including fatigue, muscle cramps, headaches, constipation, and sleep problems. 


1. How long does magnesium citrate stay in the body?

Magnesium citrate tends to remain in the body for around 40 hours in healthy individuals. However, people with a high-carb diet, blood sugar imbalances, poor kidney function, or metabolic syndrome may excrete magnesium citrate within 12 to 24 hours. 

2. Does magnesium build up in your system?

No, magnesium doesn’t build up in the body of healthy individuals as excessive levels are eliminated via the urine. However, people with certain medical conditions may have a reduced ability to excrete magnesium, which increases the risk of excess magnesium levels in the body.

3. What are the side effects of taking too much magnesium?

Although magnesium is generally well tolerated, taking too much can cause diarrhea, abdominal pain, mental confusion, drowsiness, low blood pressure, and nausea. 


4. How do you flush magnesium out of your body?

Your kidneys flush out excess magnesium levels via the urine to maintain magnesium balance. 

If you suspect you have taken too much magnesium in supplemental form, it’s best to drink plenty of water to increase urine output. If you experience symptoms such as nausea, diarrhea, confusion, or drowsiness after taking magnesium, it’s important to consult a healthcare provider.  


5. Where does magnesium get stored in the body?

The majority of magnesium is stored in bones and muscle cells. Only around one percent of the body’s magnesium stores are found in the blood. 

6. What happens when your body is low on magnesium?

Inadequate magnesium levels can impair a wide range of cellular and metabolic processes, including energy production, nerve signal transmission, blood pressure regulation, muscle function, and DNA synthesis. 

7. What are the signs of low magnesium?

Signs of low magnesium include muscle cramps, fatigue, low exercise tolerance, constipation, headaches, pins and needles, heart palpitations, and sleep issues. 

8. What are the benefits of magnesium?

Magnesium has a wide range of health benefits and has been found effective in the management or prevention of migraines, insomnia, depression, insulin resistance, asthma, and metabolic syndrome.  

9. How much magnesium can I take?

The daily recommended dietary allowance (RDA) for magnesium is between 310 and 360 mg for adult women and ranges from 400 to 420 mg for adult men. However, it may require larger doses of up to 600 milligrams to correct a deficiency and to maintain magnesium balance in individuals with poor blood sugar control, kidney problems, and diabetes. 

10. How often can I take magnesium supplements?

Because magnesium is excreted from the body within a few hours, it’s recommended to take a magnesium supplement daily to maintain magnesium balance and replenish magnesium stores. 

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