Health Experts Issue New Warning About Magnesium Supplements — Especially for These Two High-Risk Groups

Detail

Magnesium is an essential mineral involved in muscle and nerve function, blood-glucose regulation, blood pressure, and normal heart rhythm. For most healthy people, magnesium obtained from food is safe. The concern is mainly with high-dose supplements, magnesium-containing laxatives, and antacids. Office of Dietary Supplements+1

1. People With Kidney Disease

This is the most important high-risk group.

Healthy kidneys remove excess magnesium through urine. When kidney function is significantly impaired, the body may not be able to eliminate extra magnesium efficiently. This can cause hypermagnesemia (excess magnesium in the blood). Office of Dietary Supplements+1

Severe magnesium toxicity can cause:

Low blood pressure
Nausea and vomiting
Weakness
Confusion or extreme drowsiness
Difficulty breathing
Abnormal heart rhythms
In extreme cases, cardiac arrest Merck Manuals+1

People with kidney disease should not start high-dose magnesium supplements or magnesium-containing laxatives without medical advice.

2. Older Adults Taking Multiple Medications

Older adults aren’t automatically unable to take magnesium, but they may have reduced kidney function and take several medications, making interactions and excessive intake more important to consider.

Magnesium can interfere with the absorption of certain antibiotics and osteoporosis medicines such as oral bisphosphonates. Some diuretics and long-term proton-pump inhibitors can also affect magnesium levels. Office of Dietary Supplements

How Much Is Too Much?

For adults, the U.S. NIH sets an upper limit of 350 mg per day of magnesium from dietary supplements and medications unless a healthcare professional recommends otherwise. This limit doesn’t include magnesium naturally present in food. Office of Dietary Supplements

High supplemental doses commonly cause diarrhea, nausea, and abdominal cramping. Extremely high amounts can cause serious toxicity. Office of Dietary Supplements

Don’t Forget Magnesium-Containing Laxatives

A person may unknowingly consume substantial magnesium through products used for constipation or heartburn. Magnesium hydroxide and other magnesium-containing products can contribute to excessive intake, particularly when kidney function is impaired. Office of Dietary Supplements

Safer Approach

Before taking a magnesium supplement, especially if you’re older or have kidney problems:

Check how much elemental magnesium the product provides.
Tell your doctor or pharmacist about all medications and supplements you use.
Don’t assume that a higher dose is better.
Don’t use magnesium-containing laxatives regularly without medical advice.
Prefer getting magnesium from foods such as nuts, seeds, legumes, whole grains, and leafy greens when appropriate.

Bottom Line

Magnesium isn’t inherently dangerous. The biggest concern is excessive supplemental magnesium in people whose kidneys cannot eliminate it properly. If you have kidney disease or take multiple medications, check with a healthcare professional before starting a magnesium supplement. Office of Dietary Supplements+1