Electrolytes

What are electrolytes used for?

Updated 9 Nov 2026

Short answer

Rehydration has the best evidence (essential health). In children with diarrhea, oral rehydration solution worked about as well as a drip in 17 trials, though 1 child in 25 still needed the drip.[1] After exercise, drinks with sodium and sugar kept more fluid in the body than water did.[2][3] For fitness, carbohydrate-electrolyte drinks gave a small gain in endurance in warm conditions in 21 studies.[4] For gut health, a mineral water rich in magnesium sulfate eased constipation in one trial in women.[5] For heart health, potassium supplements lowered blood pressure in trials, with moderate certainty.[6] Evidence on muscle cramps is weak.[7]

Sources (7)

  1. Oral versus intravenous rehydration for treating dehydration due to gastroenteritis in children. Hartling L, Bellemare S, Wiebe N, Russell K, Klassen TP, Craig W Cochrane Database Syst Rev, 2006. PMID 16856044
  2. Oral Rehydration Beverages for Treating Exercise-Associated Dehydration: A Systematic Review, Part I. Carbohydrate-Electrolyte Solutions. Borra V, De Brier N, Berry DC, Zideman D, Singletary E, De Buck E J Athl Train, 2025. PMID 38116803
  3. Post-Exercise Rehydration in Athletes: Effects of Sodium and Carbohydrate in Commercial Hydration Beverages. Ly NQ, Hamstra-Wright KL, Horswill CA Nutrients, 2023. PMID 38004153
  4. Effects of Acute Carbohydrate-Electrolyte Supplementation on Exercise Performance in Moderate-to-Hot Ambient Conditions: A Systematic Review and Meta-Analysis. Wang X, Liang T, Liu Y, Zhang X, Zhao S, Liang Z, et al. Nutrients, 2026. PMID 42884651
  5. Efficacy and safety of a magnesium sulfate-rich natural mineral water for patients with functional constipation. Dupont C, Campagne A, Constant F Clin Gastroenterol Hepatol, 2014. PMID 24342746
  6. 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
  7. Risk Factors for Exercise-Associated Muscle Cramps: A Systematic Review With Meta-Analysis. Costa LDS, Correa VAF, de Oliveira VF, Jahn AJS, Aliano GB, Nunes GS Muscle Nerve, 2026. PMID 42693659

More about electrolytes

What are electrolytes?Do you need electrolyte drinks every day?What are the signs of low electrolytes?Are electrolyte supplements safe?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.