ElectrolytesAre electrolyte supplements safe?
Updated 9 Nov 2026
Short answer
For healthy adults, US and Canadian experts found too little evidence of harm to set an upper limit for sodium or potassium. They add that this does not mean any amount is safe.[1] The US upper limit for magnesium from supplements is 350 mg a day; more can cause diarrhea, nausea and stomach cramps.[2] Too much potassium is a risk with kidney disease and with some blood pressure and heart medicines.[3] Almost all populations eat more sodium than WHO advises.[4] In long races, drinking too much fluid can lower blood sodium to a dangerous level.[5]
Sources (5)
- Summary - Dietary Reference Intakes for Sodium and Potassium. National Academies of Sciences, Engineering, and Medicine National Academies Press (NCBI Bookshelf), 2019. www.ncbi.nlm.nih.gov
- Magnesium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
- Potassium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
- Sodium reduction. World Health Organization, 2026. www.who.int
- Exercise-associated hyponatremia. Rosner MH Semin Nephrol, 2009. PMID 19523574
More about electrolytes
What are electrolytes?Do you need electrolyte drinks every day?What are electrolytes used for?What are the signs of low electrolytes?Do electrolytes help with dehydration from diarrhea?Do electrolyte drinks improve endurance?For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.