CRN raises safe upper level for magnesium supplements after evaluation

The US Council for Responsible Nutrition (CRN) has raised its recommended safe upper level (UL) for magnesium supplements to 500 mg daily for healthy adults. The trade association bases this decision on an updated evaluation of magnesium safety, referring to new human clinical data showing higher levels are well tolerated.

Previously, the UL was set at 400 mg per day. The revision is part of CRN’s ongoing updates of its reference book, Vitamin and Mineral Safety. The organization has unveiled a new magnesium chapter and will continue releasing updated nutrient safety chapters. 

“This updated UL reflects a growing body of evidence that magnesium is well tolerated — even at higher levels than previously recognized,” says Andrea Wong, Ph.D., CRN’s SVP of 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.”

CRN aims to provide industry, practitioners, and policymakers timely access to new nutrient safety science by releasing updated chapters to its reference book. 

Other recently updated chapters include vitamin E, vitamin B6, and zinc. The ULs for these ingredients are consistent with the previous edition of the reference book. 

Magnesium market developments

CRN observes a growing appeal of magnesium in the US as a go-to supplement for overall health and wellness benefits. 

The organization’s survey data indicates that magnesium is one of the five most-used dietary supplements. In 2024, 23%, or almost one in four supplement users, took magnesium, compared to one in five in 2023. 

In addition, the survey found exceptionally high magnesium use among women and older adults and states that use tends to increase with higher household incomes. CRN notes that around 27% of female supplement users take magnesium, compared to 19% of males. People aged 55 and older report higher usage than younger adults. 

Consumers report several reasons for taking the mineral, such as helping with relaxation and improving sleep. 

CRN evaluated 60 large-scale clinical trials, finding intake of large magnesium quantities was not associated with serious adverse effects.In an interview with Nutrition Insight last week, Balchem highlighted magnesium as a “viral social media sensation” for its brain and mood health support. The company’s VP of science explains that the mineral supports the normal function of the stress hormone cortisol and contributes to mood regulation. 

At the same time, magnesium bioavailability has been flagged as an issue limiting its health benefits. Ingredient suppliers attempt to overcome absorption issues with innovations. 

For example, Balchem offers chelated magnesium, which binds mineral molecules to glycine. Lubrizol Life Science uses microencapsulation, and AIDP developed Magtain, a proprietary form of magnesium L-threonate.

Updating safety assessments

CRN’s nutrient safety evaluations focus on supplemental intakes, using risk assessments based on human clinical data. Since the previous edition of its reference book, published in 2014, the organization identified over 60 large clinical trials, none of which showed evidence that “large quantities of oral magnesium are associated with serious adverse effects in people with normal kidney function.” 

Moreover, CRN found inconsistent reports of gastrointestinal symptoms like occasional diarrhea, which were considered “nuisance effects” as opposed to health risk indicators. 

The updated UL applies to supplementing magnesium in healthy adults with normal kidney function. CRN advises people with kidney disease or related conditions should consult a healthcare provider before using magnesium-containing supplements. 

The complete fourth edition of CRN’s Vitamin and Mineral Safety reference book will be published when all chapters are finalized. Updated chapters are released when finished to give stakeholders real-time access to their conclusions.