WASHINGTON – The Council for Responsible Nutrition (CRN), the trade association for the dietary supplement and functional food industry, announced today a revised safe upper intake level (UL) for magnesium supplements, increasing the recommendation from 400 milligrams to 500 milligrams per day for healthy adults. The adjustment is based on new human clinical data demonstrating that higher levels of supplemental magnesium are well tolerated.
The updated UL is part of CRN’s ongoing release of revised nutrient safety chapters from its Vitamin and Mineral Safety (4th edition), a key reference for policymakers, health practitioners, and industry stakeholders. The magnesium chapter, released today, is the latest in a series of early-access chapters intended to provide timely insights grounded in current science.
“This updated UL reflects a growing body of evidence that magnesium is well tolerated—even at higher levels than previously recognized,” said Andrea Wong, Ph.D., CRN’s Senior Vice President, Scientific and Regulatory Affairs. “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 CRN survey data, magnesium ranks among the top five most commonly used dietary supplements, with usage increasing from 20% in 2023 to 23% in 2025. Women, older adults, and individuals in higher-income households are among the most frequent users, citing benefits such as improved relaxation and sleep.
CRN’s updated safety evaluation considered over 60 human clinical trials published since 2014. The findings confirmed that higher doses of supplemental magnesium are not associated with serious adverse effects in individuals with normal kidney function. Occasional gastrointestinal symptoms, such as diarrhea, were reported inconsistently and deemed minor “nuisance effects.”
The revised UL applies solely to supplemental magnesium for healthy adults. Individuals with kidney conditions or other medical concerns should consult a healthcare provider before taking magnesium-containing supplements.
This update follows CRN’s January 2025 release of revised vitamin B6, vitamin E, and zinc chapters. All updated chapters will be released progressively, with the complete Vitamin and Mineral Safety 4th edition to be published once all revisions are finalized.
To view the updated magnesium chapter or learn more about this resource, visit www.crnusa.org/resources/vitamin-mineral-safety.
