What Are the Side Effects of Too Much Magnesium?

Magnesium is one of the most important minerals in the human body. Side effects of too much magnesium include stomach problems, weakness, mood problems, and heart and circulation problems.

If you've ever experienced long-term stress, insomnia, or muscle pain, well-meaning friends might have recommended taking a magnesium supplement. Usually, magnesium supplements are OK to take for minor concerns, but you should use caution in certain situations. Taking too much magnesium can cause serious health problems. Learn more about this supplement and decide whether or not you could benefit from taking extra magnesium. 

Magnesium is one of the most important minerals in the human body. It's used in more than 300 enzyme interactions and is part of every cell, bone, and bit of soft tissue. Most of your body's magnesium, totaling around 25 grams, is stored within these tissues (instead of floating freely through your bloodstream). "Free" magnesium only makes up about 1 percent of the body's overall magnesium.

Magnesium is used by the human body to transport other minerals like calcium and potassium through cell membranes. Without magnesium, these substances would have difficulty entering cells and contributing their functions to the human body. Magnesium assists in regulating heart rhythms, relaxing muscles, and helping the nervous system and heart stay healthy.

Magnesium is abundant in many plant foods like nuts, leafy green vegetables, and whole grains — but some people don’t get enough through their diet. They may not eat enough foods that contain magnesium, or their bodies might have trouble absorbing the mineral. 

Supplements are a good choice if your doctor tells you that your magnesium blood levels are low — but it can be dangerous to take supplements if you don't need them. Consider whether you're having a problem in one of the following areas and visit a doctor for a thorough assessment before buying a bottle of magnesium tablets. 

Sleep

Magnesium can help your body relax. It can aid in treating conditions like insomnia, early waking, and poor sleep quality. If you are magnesium-deficient, you might have trouble falling asleep and experience fitful sleep. However, it’s important to remember that magnesium deficiency isn’t the only cause of insomnia. Talk to your doctor if you’re still having trouble sleeping after experimenting with magnesium supplements. Don’t try to treat your problems with more magnesium.

Constipation

If you feel constipated and have trouble passing stools, you might use a laxative to regulate your bowels. Magnesium citrate is a popular laxative. Other forms of magnesium can help prompt bowel movements. Be careful to calculate the correct dose: It can be difficult to tell the difference between your laxative working and taking too much magnesium.

Muscle relaxation

Magnesium supplements are often used to treat muscle spasms and cramps. This mineral relaxes muscles, but if you’re not sure you have a deficiency, you should ask your doctor before taking magnesium supplements or raise your dose if your supplements aren’t helping. There are many other reasons you could have muscle problems.

Heart health

Magnesium helps to regulate your heart rhythm. Heart rate variability (HRV), or the time between your heartbeats, is a marker of health, just as body mass index, cholesterol, and blood sugar are. Taking a magnesium supplement has been shown to improve HRV in patients with current heart failure.

Most of our magnesium comes from the food we eat. On average, men need about 400 milligrams of magnesium daily, while women need slightly over 300.

Magnesium helps the human body run efficiently — and, without it, we wouldn’t even be alive. However, too much of this essential mineral can result in mild to severe health problems, and if the toxicity isn’t treated in time, an overdose can cause death. 

It’s best to get your magnesium from your diet and only take supplements if your physician has told you it’s necessary. If you take other supplements and medications, ensure the magnesium won’t interact with them before you begin your new regimen. 

If you do take magnesium pills, tablets, or liquids, pay attention to the dosing information. If you’re smaller or larger than average, your dose might need to be adjusted based on your height and weight. Talk to your doctor to determine the correct dose for your body.

Is it possible to overdose on magnesium supplements?

Yes. Many supplements contain a day’s worth of magnesium and more. If you’re eating a healthy diet, taking a multivitamin, and taking additional magnesium supplements, you may be taking too much. 

Is it possible to overdose on magnesium in food?

It’s unlikely that you’ll ingest too much magnesium from food alone. The kidneys filter waste from the human body, including extra vitamins, supplements, and medications. Because your body tightly regulates the amount of magnesium in your bloodstream, bones, and soft tissues, it will automatically eliminate what it doesn’t need. 

For this reason, people with kidney problems should be cautious when taking magnesium supplements. Their kidneys might not be able to get rid of the extra magnesium before it builds up and causes an overdose.

The following symptoms are warning signs of a magnesium overdose. You might notice that many symptoms happen in the organs magnesium is intended to help. For example, if you take too much magnesium for constipation, you might have diarrhea. Similarly, this mineral can help the heart stay healthy in lower doses, but in too-high doses, it can cause a heart attack.

• Stomach problems: Remember that magnesium has a laxative effect. The first side effect of too much magnesium will probably be diarrhea, nausea, or even vomiting.
• Mood problems: An overdose of this mineral can affect your mood a little bit too much. In appropriate doses, it can help you relax and improve your sleep quality. In high doses, it can cause depression.
• Weakness: Magnesium is a natural muscle relaxant. In a state of magnesium toxicity, your muscles might feel weak, and you might find it hard to stay awake.
• Heart and circulation problems: Many people take magnesium for heart health, but too much can make your heart sick. An overdose can cause heart attacks, heart rhythm abnormalities, and low blood pressure.

If you've taken more magnesium than your body can process, your body will quickly let you know with stomach cramps, diarrhea, and possible dizziness. If you've taken a large overdose or feel extremely sick after taking magnesium, go to the nearest emergency room or call 911. 

Magnesium is a natural substance, but it can still cause serious health problems when you take too much. Always read the dosing instructions on your supplement bottle before deciding how much magnesium to take. Try taking the smallest dose recommended before moving to a larger one to avoid taking too much.