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.