You might believe that taking supplements is always good for your health — but when it comes to magnesium, there’s something important you should know.

The Rise of Supplement Trends

From magnesium to potassium, new supplement trends seem to pop up on social media every week. One week it’s all about boosting potassium, the next it’s “fibermaxxing.” While these trends may sound healthy, experts caution that not everyone should jump on them without understanding their personal health needs.

Magnesium, the fourth most abundant mineral in the body, is essential for many functions, including muscle and nerve activity, blood sugar control, and bone health. Many people are indeed deficient in magnesium, and some claim that taking supplements helps them sleep better or feel more relaxed. But that doesn’t mean it’s safe or necessary for everyone.

When Supplements Can Become Dangerous

Medical professionals have urged people to stop blindly following supplement trends they see online. In fact, if you fall into one of the following two categories, you should be particularly cautious before taking magnesium or any other supplement.

1. People With Kidney Problems

If you have kidney issues, magnesium supplements can be risky. According to WebMD, impaired kidneys struggle to filter excess magnesium from the body, which can lead to dangerous buildup — a condition known as magnesium toxicity.

High magnesium levels can cause severe side effects such as:

• Irregular heartbeat
• Low blood pressure
• Confusion
• Slow or shallow breathing
• Coma
• And in extreme cases, even death

Doctors strongly advise: Do not take magnesium if you have kidney problems.

2. People Without a Magnesium Deficiency

Research estimates that about 9–17% of adults and 15–20% of teenagers are magnesium deficient. Low magnesium levels have been linked to type 2 diabetes, heart disease, Alzheimer’s, and atherosclerosis (a narrowing of the arteries caused by plaque buildup).

However, if your magnesium levels are normal, taking extra magnesium won’t make you healthier — and may actually make you feel worse. Over-supplementation can cause side effects such as diarrhea, nausea, and vomiting.

Expert Opinions

Dr. Noorhan Nassar, a primary care physician at Houston Methodist, cautions that “the actual data supporting the benefits of supplementation in otherwise healthy adults isn’t complete — results are mixed and the design of these studies isn’t always ideal.”

He also adds: “There are studies showing that magnesium can have a laxative effect.”

Know How Much You Really Need

The recommended daily magnesium intake is 300 mg for men and 270 mg for women, according to the NHS. Taking more than 400 mg per day can be harmful.

Before starting any new supplement — even something as common as magnesium — it’s always best to talk to your doctor or a qualified healthcare professional.

Supplements can be helpful when used correctly, but when misused, they can do more harm than good.