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Is 500mg Magnesium Too Much?

Although the Recommended Dietary Allowances (RDAs) is a generally a trusted guideline for nutrient intake, they only provide us with the bare minimum of nutrients required by approximately 97% of healthy individuals. For magnesium, this translates to a daily recommendation of 400-420 mg for men and 310-320 mg for women. If you have a magnesium deficiency,…

Fact checked by Nattha Wannissorn

Although the Recommended Dietary Allowances (RDAs) is a generally a trusted guideline for nutrient intake, they only provide us with the bare minimum of nutrients required by approximately 97% of healthy individuals. 
For magnesium, this translates to a daily recommendation of 400-420 mg for men and 310-320 mg for women. If you have a magnesium deficiency, however, it’s not only safe and effective but possibly necessary to take more than the RDA.

Most People are Deficient in Magnesium – What’s the Best Dose to Correct a Magnesium Deficiency?

Even with the bare minimum RDA recommendation, a recent study determined that most adults only get 80-85% of that. While researchers determined RDAs based on a body weight of 133 lbs for women and 166 lbs for men, you need more magnesium for greater body weight. When considering body weight, researchers estimate adults get about 50% to 70% of RDA.

man holding a bottle of magnesium and smiling

In some circumstances, exceeding magnesium RDA is beneficial and essential for optimal health. Some of these include:

  • If you’re magnesium deficient. You can find this out by getting your magnesium levels tested. 
  • Eating a diet that is low in magnesium or hinders magnesium absorption
  • Taking large quantities of vitamin D or zinc supplements that can use up some magnesium, depleting your levels
  • Drinking alcohol or caffeine regularly

You can learn more about what factors may deplete magnesium by reading our article Food, Supplement, and Lifestyle Factors that Deplete Magnesium.

Getting enough magnesium is also essential because it helps turn on vitamin D in your body. This helps control the levels of calcium and phosphorus, which are important for healthy bones.

The amount of magnesium absorbed can vary depending on several factors, including the type of magnesium supplement and overall health. If you take too much at once, chances are you’ll have loose stools. Check out this article to learn more about magnesium absorption. 

Is 500 Mg Magnesium Too Much in a Day?

Magnesium is not a medication, even though some countries consider certain forms of magnesium as medicine. It’s a nutrient that your body needs daily to function properly. Like any other nutrients, your body is accustomed to day-to-day changes in intake. Some days you consume more magnesium, other days you consume less. 

Clinical trials examining the safety of magnesium supplementation consistently show that people can take a wide range of amounts without any significant problems. Trial daily dosages include a wide range:

Dose Type of MagnesiumWho Took MagnesiumAdverse Events
350 mg Sucrosomial® magnesium, magnesium citrate, magnesium oxide, or magnesium bisglycinateHealthy subjects to compare magnesium type bioavailabilityNone reported
500 mgMagnesium citrateHealthy overweight subjects to improve and reduce metabolic risk factorsNone reported
1600 mgMagnesium orotateOverweight individuals to improve mood and inflammatory responseNone reported
3000 mgMagnesium orotateMen struggling with infertilityNone reported

Your body can handle large amounts of magnesium because it can regulate magnesium levels to meet its needs through titration. Your body maintains a balance between how much magnesium it absorbs and how much it excretes. 

If your magnesium levels are low, your gut absorbs more and the kidneys retain more of it; if they are high, they excrete more.

With no adverse effects reported in these studies, it means that you can take magnesium in different amounts, and it is generally safe. However, it’s still important to talk to a doctor or healthcare professional before taking any supplements to ensure it’s right for you. 

It’s also important to note that some clinical trials that included larger dosages included participants with serious health concerns. 

What Happens When You Take a High Dose of Magnesium?

man holding a bottle of magnesium

So, let’s say you do take too much magnesium. What happens in your body? Let’s take a look. 

Loose Stools

Because magnesium balance is partly maintained by your intestines (along with your bones and kidneys),– it’s no surprise that you may notice a change in your stools if you take a high dose of magnesium. 

Depending on the dose and type of magnesium, your body may not absorb all magnesium ions. After ions are absorbed through the intestinal wall, the unabsorbed ions can attract water and hold it there. This makes the contents of the intestine more fluid and helps to loosen the stool, causing a laxative effect.

Some forms of magnesium are more likely to cause loose stools, such as magnesium citrate, oxide, and magnesium sulfate. This is why these forms of magnesium are often used as a treatment for constipation or as a way of clearing out the bowels for medical procedures like colonoscopies. 

Whereas, amino acids and other organic chelates such as threonate, glycinate, malate, and aspartate are gentler to the gut and don’t cause loose stools as easily. Some may even get absorbed like two-amino acid peptides.

Temporary Increase in Serum Magnesium

When you take a magnesium supplement, the magnesium ions are absorbed into the bloodstream through the intestinal wall. This causes a quick increase in your magnesium serum levels, which is the magnesium in the water portion of your blood.

A meta-analysis of 16 clinical trials examined the effects of taking magnesium supplements on serum magnesium levels. Those taking magnesium supplements ranging from 50 to 500 mg daily had significantly higher serum levels than those not taking supplements.

While taking a large dose of magnesium can rapidly increase your magnesium serum levels, it’s important to note that it doesn’t quickly change your body’s overall magnesium levels. Only 1% of your body’s magnesium is in your serum, while the rest is in your bones and tissues.

From the serum, magnesium ions circulate in the bloodstream and are transported to various tissues and organs where needed.

The type of magnesium you take will determine how much your cells absorb. Some forms of magnesium are more bioavailable in cells than others. Research tells us that Sucrosomial magnesium and magnesium glycinate are particularly bioavailable. 

A study compared the absorption of Sucrosomial magnesium to other forms. Within 24 hours, the magnesium levels in subjects’ red blood cells were significantly higher with Sucrosomial magnesium than in other forms.

Another clinical trial highlighted the bioavailability of magnesium glycinate compared to magnesium oxide. Subjects took 100 mg of both forms of magnesium, but magnesium glycinate was better absorbed.

Removal by the Kidneys

Your kidneys tightly regulate your magnesium serum levels. If you take too much magnesium and your cells aren’t using it, your magnesium serum levels become elevated. 

This signals your kidneys to help excrete the excess magnesium through urine to maintain the balance. This means if you take a lot of magnesium at once, you may lose more of it in your urine rather than be able to use it in your tissues. 

Unabsorbed Magnesium Is Excreted in the Stool

We discussed how magnesium enters your bloodstream through your intestines and goes to your cells. 

But you don’t absorb all of the magnesium in your gut, especially when you take more than you need. What isn’t absorbed gets excreted through your feces or stool. This is also where loose stools or even diarrhea come into play. 

Who Should Be Concerned About Taking High Doses (500 mg or more) of Magnesium (and Check with Their Doctors)?

While taking 500mg of magnesium is safe for most people, some should be more cautious. Please note that we’re not suggesting that our products can treat any condition, and we’re including this caution for informational purposes.

People Taking Certain Medications

Medications can change how your body processes minerals, including magnesium. 

Some use the same transport and metabolism pathways in the body for their intestinal absorption, metabolism, and elimination. This includes:

person about to take one pill of magnesium
  • Antibiotics such as aminoglycosides, tetracyclines, and quinolones
  • Bisphosphonates, like alendronate, commonly used to treat osteoporosis. Magnesium can decrease bisphosphonate absorption.

Other medications are more likely to cause magnesium loss by increasing urine excretion. These include:

  • Diuretics 
  • Antacids, especially proton pump inhibitors (PPIs)

Taking magnesium with blood pressure medication can lead to low blood pressure. Calcium channel blockers treat high blood pressure by blocking calcium from entering cells. Magnesium can also block calcium entry and lead to excessively low blood pressure when taken together.

People with Kidney Issues

If you have kidney issues, taking high amounts of magnesium is probably not a good idea. The kidneys help control the levels of magnesium in your body. When the kidneys aren’t working properly, they may be unable to get rid of excess magnesium. This can cause the levels of magnesium in the serum to become too high, which can harm your organs and body functions.

However, magnesium supplementation may be beneficial in certain cases, and this should be decided in consultation with your doctor.

People with Gastrointestinal Disorders

If you already struggle with stomach cramping and diarrhea, you should be cautious when considering taking a high dose of magnesium. Magnesium supplements can sometimes cause gastrointestinal side effects. These symptoms can be worse in individuals with pre-existing gastrointestinal issues.

People at Risk of Heart Failure

While magnesium plays a critical role in heart health, there are times when you should be cautious. When heart failure patients have too much magnesium, it can harm their health. 

A meta-analysis explored the effects of having too much or too little magnesium on heart failure patients. Researchers determined that high magnesium levels affect the heart’s channels, causing irregular heartbeats and worse outcomes. It also affects the release of a chemical called acetylcholine, making muscles less responsive. This leads to problems like:

  • Irregular heart rhythms 
  • Widened blood vessels 
  • Weak heart muscle 
  • Low blood pressure

Before starting any supplement, it’s important to consult a healthcare professional who can assess your specific condition and provide personalized advice regarding magnesium use.


If you’re healthy, exceeding magnesium RDA and taking 500 mg a day is absolutely safe. If you take too much, you can just expect loose stools. If you’re considering taking a higher dose of magnesium,  a great place to start is by:

  • Getting your magnesium levels tested. You can learn the best way to determine your levels in this article
  • Working with your health practitioner to determine what’s best for you and your health concerns. 

When choosing a magnesium supplement, make sure it’s high-quality with the right balance of various types of magnesium, like Magnesium Breakthrough

Magnesium Breakthrough contains seven forms of highly-bioavailable magnesium designed to deliver magnesium to your cells and not just increase your serum levels

Shop Magnesium Breakthrough Today
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  1. Deb Nelson on October 21, 2023 at 8:00 am

    Good morning, I’ve purchased both magnesium and the sleep formula. Unfortunately I have peripheral neuropathy due to radiation (DCIS). My neurologist check my B6 levels and they were .too high. I can no longer take B6. It seems all your magnesium includes it. Is that correct? Any input or other good brands that will metabolize without B6. I’ve searched and can only find basic magnesium so it’s likely not metabolizing.
    Thanks so much,
    Deb Nelson
    425-502-2566 (text)
    [email protected]

    • Ann-Marie on October 23, 2023 at 10:59 pm

      Hello Deb,

      My name is Ann-Marie, and I am a Happy Health Concierge here at BiOptimizers!

      That is correct our Magnesium Breakthrough capsules and powder contain B6. I have done some checks and sent you an email regarding where you may be able to find Magnesium supplements without B6.

      If you have any other questions, please email us at [email protected]

      Take care and have a nice day!

      My very best regards,
      Happy Health Concierge

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