Are You Taking Too Much Magnesium? Experts Reveal How to Tell

If you’re not getting enough magnesium from your diet, supplements are a simple way to meet your body’s needs. Getting enough magnesium helps maintain optimal muscle and nerve function and regulates blood pressure and blood sugar levels, per the National Institutes of Health (NIH). However, overdoing it on magnesium can also cause problems, so being able to recognize the signs you’re taking too much magnesium can help keep you in the healthy range.

“Taking too much magnesium over the long term can be harmful to your health because it may lead to an electrolyte imbalance, which can affect heart function and interfere with the normal functioning of other body systems,” explains Diane Han, M.P.H., R.D., a dietitian based in San Francisco and the founder of Woking Balance Wellness.

Meet the experts: Diane Han, M.P.H., R.D., a dietitian based in San Francisco and the founder of Woking Balance Wellness; Vanessa Imus, M.S., R.D.N., a registered dietitian nutritionist and owner of Integrated Nutrition for Weight Loss in Bothell, Wash.

According to the NIH, the recommended daily intake of magnesium is 320 milligrams (mg) for women and 420 mg for men, achieved through a combination of diet and supplementation. Read on to discover the signs that you may be taking too much magnesium, plus how to limit these side effects, and if it’s possible to get too much magnesium from your diet alone.

While taking too much magnesium in the long term can be damaging to your health, it can also cause unpleasant symptoms in the short term. According to Han, the most common signs that you are overdoing it on magnesium include diarrhea, nausea, and stomach cramps. These symptoms can result from regularly taking more magnesium than your body needs or is able to process.

The NIH explains that if you take a laxative or antacid that contains an extremely large dose of magnesium (over 5,000 mg), you may experience something called magnesium toxicity. This is when you may have more serious symptoms, such as low blood pressure, vomiting, urine retention, muscle weakness, difficulty breathing, irregular heartbeat, or even cardiac arrest in extreme cases. Your risk of these symptoms is much higher if you have kidney disease or kidney failure, which means your body will have difficulty removing excess magnesium, per the NIH.

“It’s pretty difficult for most people to reach their daily magnesium needs through food, and I have yet to see someone getting too much magnesium from their diet. This typically only happens with over-supplementing,” says Vanessa Imus, M.S., R.D.N., a registered dietitian nutritionist and owner of Integrated Nutrition for Weight Loss in Bothell, WA. That’s because even the foods that contain the most magnesium, such as pumpkin seeds and chia seeds, contain only 37% and 26% of your daily needs, respectively. Add in the facts that only 30% to 40% of dietary magnesium is typically absorbed by the body, per the NIH, and that your body does have the ability to remove some excess, it’s tough to get too much from your diet alone.

“Foods contain a natural matrix of nutrients that work together in balanced proportions,” adds Han. “This balance helps the body regulate nutrient intake and supports normal physiological function, reducing the risk of nutrient imbalances that can occur when individual nutrients are consumed in isolation.”

The good news: If you start to experience any of the gastrointestinal side effects associated with taking too much magnesium on a regular basis, it’s relatively easy to get rid of them. The first thing you should do is lower your dose. The NIH notes that the tolerable upper intake level for supplemental magnesium is 350 mg for adults, so if you’re taking more than that per day, try dropping your dose and waiting to see if symptoms disappear.

You could also try switching to a different type of magnesium. Imus explains that GI symptoms are most common with magnesium oxide and magnesium citrate, but “switching to magnesium glycinate or magnesium malate can help meet your daily needs through supplementation without strong laxative effects.” And don’t forget to choose a supplement with a third-party quality assurance label, Han adds.

If you’re unsure what to do, speaking with a dietitian or healthcare provider can help point you in the right direction. Getting enough magnesium is very important for your overall wellness, but it should never come at the expense of your day-to-day health.

Dietary supplements are products intended to supplement the diet. They are not medicines and are not intended to treat, diagnose, mitigate, prevent, or cure diseases. Be cautious about taking dietary supplements if you are pregnant or nursing. Also, be careful about giving supplements to a child, unless recommended by their healthcare provider.