Effects of Too Much Magnesium and Ways to Avoid It

Your body needs magnesium to handle many biological processes. About half of all the magnesium in your body comes from your bones, but your body uses magnesium to help regulate blood sugar, blood pressure, nerve function, muscle movement, and energy metabolism. While magnesium is important, excessive magnesium can lead to certain problems. Therefore, it is important to talk to your doctor before you start taking a magnesium supplement. Let's find out more about it.

What Happens If You Eat Too Much Magnesium?

If you are not already deficient in magnesium and start taking a supplement, you may end up developing certain health complications. Here are some possible side effects associated with magnesium toxicity.

1. You Develop GI Problems

Magnesium toxicity will first affect your gastrointestinal system. Diarrhea is usually the first symptom because magnesium works as a laxative. You may also experience other GI symptoms, such as nausea, stomach upset, abdominal cramps, and vomiting. Keep in mind that it is less likely to develop magnesium toxicity if you are taking magnesium from dietary sources alone. Anything less than 350mg/day is usually considered safe.

2. You Develop Cardiovascular Problems

Magnesium toxicity can affect your cardiovascular system in a negative way. Your blood pressure may drop quickly and lead to a condition called hypotension. Taking too much magnesium is also associated with problems like erratic heart rhythms or slow heartbeat. Very high levels of magnesium in the blood can also lead to cardiac arrest.

3. You Experience Kidney Damage

Excessive magnesium in your body is harmful for your kidneys. Magnesium toxicity impairs your kidneys' ability to remove unwanted magnesium from the blood. If you already have another kidney disease due to alcoholism, you may experience life-threatening complications due to magnesium toxicity. Therefore, you should first talk to your doctor before increasing your intake of magnesium.

4. You Experience Other Symptoms

Severe magnesium toxicity can lead to several other problems, such as difficulty breathing and muscle weakness. This toxicity can affect you mentally and make you feel confused and lethargic. High levels of magnesium can disrupt the natural balance of minerals in the body and lead to serious consequences.

How Much Magnesium Is Too Much?

It is clear that taking too much magnesium can have side effects, but you also need to know exactly how much is considered too much. The following table shows the current RDAs for magnesium according to the NIH:


RDA for Magnesium

6 months


7 to 12 months


1 to 3 years


4 to 8 years


9 to 13 years


14 to 18 years

360mg for women and 410mg for men

19 to 30 years

310 mg for women and 400mg for men

31 years and older adults

320mg for women and 420mg for men

Moreover, pregnant women should be getting 350-360mg of magnesium every day, whereas breastfeeding mothers should get at least 310-320mg of magnesium a day.

It is important to note that magnesium is important because it helps maintain a balance among other nutrients within the body, including vitamin K, calcium, and vitamin D. You have high levels of calcium in your body and you need a good amount of magnesium to counter balance those high levels. It also means that if you are taking calcium supplements or vitamin D supplements, this will automatically lower the levels of magnesium in your body.  That is the reason why you should talk to your doctor before you take any dietary supplement.

Dietary Sources of Magnesium

If you are deficient in magnesium, you do not always need to take a supplement. You can get a good amount of magnesium from various dietary sources to avoid taking too much magnesium. Here are some examples:

1. Dark Leafy Greens

Dark leafy greens are nutrient powerhouse and provide you with a variety of vitamins and minerals. You can opt for cooked or raw baby spinach, kale, collard greens, or Swiss chard to increase your intake of magnesium without having to increase your caloric intake.

2. Nuts and Seeds


You get about 100% of your RDA for magnesium from a half cup of pumpkin seeds. Other nuts and seeds are also rich in magnesium. Some good examples include sunflower seeds, almonds, pine nuts, cashews, Brazil nuts, and pecans.

3. Fish

You can include fish in your diet to increase your intake of magnesium. Fish also provides you with vitamin D and healthy omega-3 fatty acids that help improve your cardiovascular health. Some good examples are wild salmon, mackerel, tuna, and halibut. Eating fish at least once a week will help you get enough magnesium and other important nutrients for better health.

4. Soybeans

Soybeans are laden with important nutrients, including vitamins, amino acids, minerals, and fiber. You get about half of your recommended daily intake of magnesium from a half-cup serving of dry roasted soybeans. You can add shelled soybeans to your diet and enjoy the same benefits. Other legumes are also quite beneficial. Some good examples of magnesium-rich legumes are kidney beans, black beans, chickpeas, white beans, lentil, and black-eyed peas.

5. Avocado

Packed with multivitamins, avocados provide you with loads of magnesium as well as many heart-healthy nutrients. Avocados are among the most nutritious produce picks, with a sliced avocado offering you 15% of your recommended daily intake of magnesium.

6. Bananas

When it comes to increasing your magnesium intake, you just cannot keep bananas out of the list. While bananas are usually known for their high potassium content, they are also quite rich in magnesium. Even a medium-sized banana provides you with 32mg of magnesium. It also provides you with fiber and vitamin C with 100 calories only.