Safe intake level for magnesium supplements raised after updated evaluation from CRN

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In a recent press release, the Council for Responsible Nutrition (CRN; Washington, D.C.), announced that the trade association for the dietary supplement and functional food industry had finished their evaluation of magnesium safety. From this evaluation, the recommended safe upper level (UL) of magnesium supplements has been raised to 500 mg per day for healthy adults. The change comes from new clinical data that reflected higher levels as being well tolerated. Previously, the safe UL for magnesium had been 400 mg per day.

The new magnesium chapter in the association's Vitamin and Mineral Safety, a foundational resource which was originally authored by the late Dr. John Hathcock, was recently released and is a part of a series of updates which will assist practitioners, policymakers, and the industry with the latest science in regard to nutrient safety.

“This updated UL reflects a growing body of evidence that magnesium is well tolerated—even at higher levels than previously recognized,” said Andrea Wong, PhD, CRN’s senior vice president of scientific and regulatory affairs, in the press release. “For formulators of magnesium supplements to support bone, muscle, nerve, or heart health, this offers greater confidence in the safety of levels up to 500 mg/day.”

According to the press release, magnesium is one of the top five most used dietary supplements. CRN survey data showed that almost one in four supplement users consume magnesium. This is up 23% from 2023 where magnesium was consumed by on in five supplement users. The nutritional supplement was additionally shown to be used more with women and older adults over 55, as well as those with higher household incomes. Magnesium users explained that the supplement has helped with better sleep and relaxation. The press release mentioned that more than 60 clinical trials since 2014 highlighted in the update have detailed that there was no evidence supporting large quantities of oral magnesium were linked to serious adverse effects in individuals with normal kidney function. There were some gastrointestinal symptoms reported for example, occasional diarrhea, which was inconsistently reported and was labeled as “nuance effects” and not an indicator of health risk.

With the updated safe UL, people suffering from kidney disease or related conditions were recommended in the press release to discuss with their healthcare provider on usage of magnesium supplements.

New updates to chapters in Vitamin and Mineral Safety will be released on a rolling basis which will allow stakeholders to have real-time access to updated safety conclusions. Once it has been finished, the fourth edition will be published. To learn more about the updated magnesium chapter please visit¹: https://www.crnusa.org/resources/vitamin-mineral-safety.

Reference

1. Vitamin & Mineral Safety https://www.crnusa.org/resources/vitamin-mineral-safety (accessed Apr 29, 2025).