The Study
Caffeinated Energy Drink Formulations Differentially Impact Hydration Versus Water: Does Habitual Caffeine Intake or Biological Sex Matter?
This study tested different energy drinks on people to see which ones keep you hydrated better than water. It found that some drinks with caffeine and electrolytes worked just like water, but others didn't. But it didn't prove that caffeine itself makes you dehydrated—it just showed that certain drinks, with their mix of ingredients, behaved differently.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Some energy drinks make you pee more than water, but others don't — it depends on what’s in them, not just the caffeine.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 572 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — if you drink energy drinks, choosing ones with electrolytes and sugar (like sports drinks) helps you stay hydrated, even with caffeine.
- 2High-caffeine, low-electrolyte drinks may dehydrate you.
- 3Drink with 106 mg caffeine + salt + sugar: hydrates like water.
- 4Drink with 280 mg caffeine + little salt/sugar: makes you lose 14% more fluid than water.
- 5Women kept more fluid than men, even with more caffeine per pound.
- 6Habitual caffeine drinkers didn’t hydrate better.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Nutrients
Year
2025
Authors
Melinda Millard-Stafford, Brian Hack, Alec Harp, Ella Smith
Related Content
Claims (6)
A caffeinated energy drink with 106 mg of caffeine, electrolytes, and carbohydrates hydrates the body as effectively as water in healthy adults after 240 minutes, according to the Beverage Hydration Index.
Drinks with 280 mg of caffeine and minimal electrolytes or carbohydrates result in 9–14% less hydration efficiency than water after 240 minutes, as measured by the Beverage Hydration Index.
People who regularly drink small amounts of caffeine (up to 156 mg per day) do not retain more or less fluid after consuming caffeinated energy drinks compared to when they do not consume them, based on measurements taken 2 and 4 hours after drinking.
After drinking caffeinated energy drinks, women retain more fluid than men, as shown by higher hydration scores and less urine produced after 240 minutes, even though women consume more fluid and caffeine relative to their body weight.
Energy drinks containing electrolytes and carbohydrates retain 24.8% more fluid over 240 minutes than drinks with caffeine alone.
Drinks that contain electrolytes, carbohydrates, and food components hold more fluid in the body over four hours than plain water.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.