Too Much Magnesium: Understanding Symptoms, Causes, and Risks

Have you taken too much magnesium? Here you can learn about the typical symptoms and risks of magnesium overdose. We explain the causes and provide tips for treatment. Read on to find out everything important about excessive magnesium.

The most important points at a glance

• Magnesium overdose can result from kidney insufficiency or excessive intake of supplements and cause dangerous symptoms. However, a true overdose occurs very rarely.

• Important symptoms of severe overdose include impaired consciousness, muscle weakness, diarrhea, and in the worst case, cardiac arrhythmias. However, diarrhea is usually the most common side effect of a mild overdose.

• For individuals with health risks such as kidney disease, medical consultation before taking magnesium supplements is important.

What is magnesium overdose?

Magnesium overdose, also known as hypermagnesemia, occurs when the magnesium level in the blood is too high and can cause potentially dangerous symptoms. Magnesium is an essential mineral that plays a crucial role in the nervous system, energy metabolism, and muscle function. So it’s no surprise that an imbalance can lead to serious health problems.

The body primarily regulates magnesium levels through the kidneys, which excrete excess magnesium via urine. However, if kidney function is impaired or there is excessive intake of magnesium supplements, a dangerous increase in magnesium levels in the blood can occur. Blood or urine tests are often necessary to check magnesium concentration and diagnose an overdose. A true overdose is, however, very rare and usually only occurs with excessive use of dietary supplements.

A balanced magnesium intake is crucial to avoid both magnesium deficiency and magnesium excess.

But how do you recognize an overdose and what symptoms occur?

Symptoms of magnesium overdose

The symptoms of magnesium overdose can be varied and range from mild to serious signs. The most common symptoms of severe magnesium overdose include impaired consciousness and muscle weakness. These may manifest as dizziness, confusion, and general exhaustion. Nausea and vomiting are also not uncommon in cases of magnesium overdose.

More severe symptoms include a slowed heart rate and respiratory depression. High magnesium concentration in the blood can also lead to dangerously low blood pressure. It is important to recognize these symptoms early to avoid serious health consequences.

A common side effect of mild overdose is diarrhea, which is caused by elevated magnesium levels and can lead to significant gastrointestinal discomfort.

But what are the main causes of such an overdose?

Causes of magnesium overdose

The main causes of magnesium overdose are kidney insufficiency and the excessive intake of magnesium-containing supplements. The kidneys play a central role in regulating magnesium levels by excreting excess magnesium. However, if the kidneys do not function properly, this can lead to a dangerous increase in magnesium levels, which in severe cases can result in magnesium overdose.

In addition to kidney insufficiency, excessive intake of magnesium can also lead to hypermagnesemia. It becomes particularly dangerous when people take very high doses of magnesium supplements without medical supervision. Weakness of the parathyroid glands can also be a cause of excess magnesium in the blood. However, it is important to emphasize that a true overdose is very rare.

It is crucial to understand the causes of magnesium overdose in order to take preventive measures.

But when does magnesium really become dangerous?

When does magnesium become dangerous?

An investigation by the Consumer Advice Center showed that 64% of the tested magnesium supplements contained more than the recommended maximum daily dose of 250 milligrams. This highlights the need to pay attention to dosage.

A dangerous accumulation of magnesium in the body (hypermagnesemia) is rare and usually occurs only with very high intake through dietary supplements or in individuals with impaired kidney function. In healthy people with normally functioning kidneys, it is difficult to reach dangerous magnesium levels through regular diet or moderate supplementation.

Acute magnesium poisoning can occur when extremely high doses are taken, for example, several grams per day (over 5 grams). Such amounts are far above typical supplement dosages and would rarely occur in practice.

Excessive magnesium content can be detected through a blood test. Typically, the normal serum magnesium level is about 0.7 to 1.0 mmol/l. Values between 1.0 and 1.3 mmol/l are already considered slightly elevated (mild hypermagnesemia). A moderately elevated concentration lies between 1.4 and 2.0 mmol/l. Strongly elevated values above 2.0 mmol/l can be critical, and an overdose can become life-threatening at a blood serum concentration above 2.5 mmol/l.

Summary of serum magnesium levels:

• Normal range: 0.7 – 1.0 mmol/l

• Slightly elevated: 1.0 – 1.3 mmol/l

• Moderately elevated: 1.4 – 2.0 mmol/l

• Strongly elevated: Above 2.0 mmol/l

• Life-threatening: Above 2.5 mmol/l

The recommended total daily intake of magnesium according to the DGE (German Nutrition Society) is 300 mg for women and 350 mg for men. The BfR (Federal Institute for Risk Assessment) recommends taking additional magnesium in a maximum dosage of 250 mg per day to avoid overdoses. A true overdose is, as explained, very rare.

What risks and side effects can occur in the event of an overdose?

Risks and side effects of magnesium overdose

Untreated severe hypermagnesemia can be life-threatening. An excessively low magnesium level in the blood increases the risk of cardiac arrhythmias. It becomes particularly dangerous when magnesium supplements are taken in combination with blood pressure medications. This can lead to a significantly slowed heart rate and, in the worst case, to cardiac arrest.

A sudden drop in heart rate can also be caused by magnesium overdose. Patients with a slowed heart rate below 60 beats per minute should avoid magnesium supplements. Although magnesium has a positive effect on heart function, an overdose can have the exact opposite effect and lead to severe health problems.

The risks and side effects of excessive magnesium should not be underestimated, even though a true overdose is very rare. But how can such an overdose be treated?

Treatment of magnesium overdose

The treatment of a magnesium overdose may include diuretics or dialysis, especially in cases of advanced renal insufficiency. Diuretics promote the excretion of magnesium through urine but are primarily used as a side effect. It is important to note that other essential minerals and vitamins can also be flushed out in the process.

In patients with severe renal insufficiency, dialysis is often necessary to remove excess magnesium and toxins. Such treatment should be carried out as early as possible to avoid serious complications.

Timely treatment is crucial to restore health and prevent further damage.

But how can a magnesium overdose be avoided in the first place?

Prevention: How to avoid a magnesium overdose?

Before taking dietary supplements, the dosage on the packaging should be carefully observed.

Unpleasant gastrointestinal complaints can already occur with a daily intake of more than 300 mg. However, tolerability also depends on the choice of magnesium compound. Organic and highly bioavailable compounds such as Magnesium glycinate or Magnesium Malate are very well tolerated and offer additional benefits due to their binding partners. In another blog post, we analyzed and compared the most well-known magnesium compounds: Which magnesium is the best?

Products that contain significantly more than 100% of the reference amount of micronutrients are often unnecessary and should be avoided to prevent overdoses. Patients with kidney diseases should be particularly cautious, as their ability to excrete magnesium is limited, which increases the risk of an overdose.

With these preventive measures, the risk of a magnesium overdose can be significantly reduced.

But when is the additional intake of magnesium actually useful?

When is the additional intake of magnesium useful?

The additional intake of magnesium can be useful if the need cannot be met through a normal diet. The need for magnesium may also be increased depending on life circumstances. This includes athletes, pregnant women, seniors, people under stress, migraine sufferers, or individuals with certain eating habits such as vegans.

Athletes have an increased magnesium requirement due to the heightened muscle metabolism and the loss of magnesium through sweat. Studies have shown that magnesium plays a crucial role in energy production and muscle function. It has been proven that magnesium supplementation can improve muscle strength and physical performance in older individuals (Zhang et al., 2017).

During Pregnancy the need for magnesium increases to support fetal development and avoid potential complications such as preeclampsia. Additional magnesium intake has been associated with a reduction in pregnancy complications like preeclampsia and a lower risk of preterm births (Makrides et al., 2014) (Zarean & Tarjan, 2017).

Seniors may have an increased need due to reduced magnesium absorption with age or decreased kidney function. A study showed that magnesium supplementation could improve mobility and muscle strength in older women participating in a moderate fitness program. (Veronese et al., 2014).

People who suffer from chronic stress consume more magnesium because stress hormones like cortisol can lower magnesium levels in the body. Magnesium showed a positive effect on reducing stress and anxiety in susceptible individuals. (Boyle et al., 2017).

Migraine patients often benefit from magnesium supplements as magnesium can help reduce the frequency and intensity of migraine attacks. A review study found that magnesium can be an effective prophylaxis for migraines, especially in patients with known magnesium deficiency. (Teigen & Boes, 2015).

Additionally, Vegans and vegetarians often have difficulty obtaining sufficient magnesium through their diet, as magnesium-rich foods like nuts, seeds, and whole grains may not be consumed in adequate amounts.

Moreover, certain health conditions such as Diabetes, Digestive disorders (e.g., Crohn's disease or celiac disease) and chronic inflammation can increase magnesium requirements or impair absorption. (Veronese et al., 2020). The use of certain medications, such as diuretics or proton pump inhibitors, can also lower magnesium levels in the body.

Frequently Asked Questions

How much magnesium per day?

The DGE recommends a daily intake of 350 to 400 mg of magnesium for men and 300 to 350 mg for women. If you are pregnant or engage in a lot of sports, your requirement might even be higher. Important: This recommendation takes into account the total amount absorbed through food and dietary supplements. In another blog post, we went into more detail about the question "How much magnesium per day?" .

What are the side effects of taking magnesium daily?

Taking magnesium daily can cause bloating and gastrointestinal issues like loose stools or diarrhea. Your body tries to get rid of the excess quickly!

Is 400 mg of magnesium too much?

400 mg of magnesium is generally not too much as long as you're not taking it exclusively as a dietary supplement. Please note that you already absorb significant amounts of magnesium through your daily diet.

What symptoms occur with too much magnesium?

In the case of a mild overdose, the body usually reacts with diarrhea. Severe and dangerous symptoms from significantly too much magnesium include nausea, muscle weakness, low blood pressure, and a slow heart rate.

What are the main causes of magnesium overdose?

The main causes of magnesium overdose are kidney insufficiency and the excessive intake of magnesium-containing supplements.