Electrolytes
A systematic review found carbohydrate-electrolyte drinks rehydrated people better than water after exercise dehydration. Prospective studies did not link dehydration or blood sodium to muscle cramps. Prior cramping and faster pace did. Salt capsules changed race time in one trial and not another. Hyponatremia in ultramarathoners tracked overdrinking, not low sodium intake.
Add to Bio HackChecked 2026-11-09
- Status
- Food or dietary supplement in the US, depending on labeling.
- Also called
- electrolyte drink mix, hydration multiplier, oral rehydration solution, ORS, salt tablets, salt capsules, sodium supplements, LMNT, Liquid IV, Nuun, sports drink, pickle juice
- Taken for
- hydration, rehydration after exercise, preventing cramps, endurance in the heat, preventing hyponatremia, energy
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Shown to help2
Reported risks2
What people take it for, and what was found
Shown to help2
Rehydration after exercise
Shown to improve rehydration after exercise over water on many outcomes, most with drinks of 4% to 9% carbohydrate.
The numbers and sources
- Effect
- Across 19 controlled trials comparing carbohydrate-electrolyte drinks (0% to 9% carbohydrate) with water after exercise dehydration, drinks of 0% to 3.9% and especially 4% to 9% carbohydrate showed a rehydration benefit on many outcomes [1].
- Population
- Adults and children dehydrated by exercise [1].
- Sources
- [1]
- Caveats
- Study variability was high and the abstract gives no pooled numbers [1].
Stopping a cramp in progress
One small trial found about 74 mL of pickle juice shortened induced foot cramps by 49 seconds against water in dehydrated men.
The numbers and sources
- Effect
- In dehydrated men with electrically induced foot cramps, about 74 mL of pickle juice shortened cramp duration by 49.1 seconds against water (84.6 against 133.7 seconds). Blood electrolytes barely changed in 5 minutes, and the authors attribute the effect to a reflex from the mouth and throat, not electrolyte replacement [5].
- Population
- Hypohydrated men, small lab study [5].
- Sources
- [5]
- Caveats
- Induced cramps in one small foot muscle, not cramps during sport.
Mixed results2
Preventing exercise-associated muscle cramps
Mixed results: in athlete studies, hydration and blood electrolytes did not predict cramps, while a trial review reported sodium solutions reduced cramp susceptibility.
The numbers and sources
- Effect
- Across 9 longitudinal studies (11,274 participants) and 36 meta-analyses, prior cramping raised the odds of cramping about 4.4-fold. Hydration and most other factors showed no consistent association. People who cramped had higher post-race potassium and magnesium, not lower [2]. In 210 Ironman triathletes, serum electrolytes and body weight change did not differ between the 43 who cramped and those who did not; faster race times and cramp history predicted cramping [3]. A 2026 systematic review of 13 trials of electrolyte supplements for cramps or muscle pain reported that sodium-based solutions reduced cramp susceptibility during exercise and in cirrhosis, and found no supporting evidence for calcium or potassium [4].
- Population
- Endurance athletes in prospective cohorts [2][3]; randomized or quasi-randomized trials, mostly of magnesium [4].
- Sources
- [2], [3], [4]
- Caveats
- Sources [2] and [3] are observational studies of risk factors, not trials of electrolyte products. Most findings rested on limited evidence [2]. The trial review gives no pooled number for sodium in its abstract, and 10 of its 13 trials tested magnesium [4].
Endurance performance
Small trials found mixed results: salt capsules lowered half-ironman race time in one, and sodium did not change cycling performance in two others.
The numbers and sources
- Effect
- In 26 triathletes, salt capsules (113 mmol sodium) before and during a half-ironman produced a lower total race time than placebo (p = 0.04) and higher post-race serum sodium; strength and jump loss did not differ [6]. In 9 cyclists, 700 mg an hour of salt did not change a 72 km time trial in cool conditions (171 against 172 minutes) [7]. In 12 trained endurance athletes, a dextrose and sodium drink taken 60 and 30 minutes before cycling did not change time to exhaustion (p 0.703), power output or peak oxygen uptake against mineral water [8].
- Population
- Trained triathletes in a race [6]; trained cyclists at 13.8°C [7]; 12 trained endurance athletes aged 20 to 35 in a crossover trial [8].
- Sources
- [6], [7], [8]
- Caveats
- Three small trials with mixed results under different conditions. The 2025 trial gave its drinks only before exercise [8]. No meta-analysis of sodium for endurance was located.
Doses studied
Rehydration trials compared drinks of 0% to 9% carbohydrate with water [1]. Race trials used 113 mmol of sodium across a half-ironman [6] and 700 mg of salt an hour across about 3 hours of cycling [7]. The pickle juice trial used 1 mL per kg body weight [5]. The pre-exercise trial used 300 mL servings of a dextrose and sodium drink 60 and 30 minutes before cycling [8].
Risks
Reported risks2
Hyponatremia from overdrinking
In one ultramarathon, 6.6% of finishers had hyponatremia though 93.9% used sodium supplements. It was linked to overdrinking, not to sodium intake.
The numbers and sources
- Effect
- At the 161 km Western States race, 6.6% of finishers had hyponatremia even though 93.9% used sodium supplements. Sodium intake rate did not differ between hyponatremic and normal finishers. No hyponatremic finisher lost more than 4.3% of body weight, consistent with overdrinking [9].
- Population
- Ultramarathon finishers, 53.0% of 296 finishers with both survey and blood data [9].
- Sources
- [9]
- Caveats
- One race, observational. The authors identify overhydration as the primary characteristic of those who developed hyponatremia [9].
Sodium intake and blood pressure
Shown to lower systolic pressure about 4 mmHg when salt is cut by about 4.4 g a day, in adults with and without hypertension.
The numbers and sources
- Effect
- Across 34 trials (3,230 participants) of at least 4 weeks, cutting salt by about 4.4 g a day lowered systolic pressure by 4.18 mmHg (95% CI -5.18 to -3.18) and diastolic by 2.06 mmHg. Each 6 g a day less salt was linked to 5.8 mmHg lower systolic pressure [10].
- Population
- Adults with and without hypertension [10].
- Sources
- [10]
- Caveats
- These trials lowered usual salt intake; they did not test electrolyte mixes or people with high sweat losses.
Claims tested and not found
- That cramps come from low electrolytes or dehydration. Prospective studies found no consistent link, and people who cramped had higher potassium and magnesium after races [2][3].
- That sodium supplements prevent hyponatremia during long events. Sodium use did not differ between runners who did and did not develop it [9].
Sources
- Borra V, De Brier N, Berry DC, et al. Oral Rehydration Beverages for Treating Exercise-Associated Dehydration: A Systematic Review, Part I. Carbohydrate-Electrolyte Solutions. Journal of Athletic Training. 2025. https://doi.org/10.4085/1062-6050-0682.22
- Costa LS, Correa VAF, de Oliveira VF, et al. Risk Factors for Exercise-Associated Muscle Cramps: A Systematic Review With Meta-Analysis. Muscle and Nerve. 2026. https://doi.org/10.1002/mus.70389
- Schwellnus MP, Drew N, Collins M. Increased running speed and previous cramps rather than dehydration or serum sodium changes predict exercise-associated muscle cramping: a prospective cohort study in 210 Ironman triathletes. British Journal of Sports Medicine. 2010. https://doi.org/10.1136/bjsm.2010.078535
- Patil S, Falkowski A, Venkataiah VS, et al. The Role of Electrolytes in Muscle Pain Syndromes: A Systematic Review and Meta-Analysis With Implications for Temporomandibular Disorder. International Dental Journal. 2026. https://doi.org/10.1016/j.identj.2026.109488
- Miller KC, Mack GW, Knight KL, et al. Reflex Inhibition of Electrically Induced Muscle Cramps in Hypohydrated Humans. Medicine and Science in Sports and Exercise. 2010. https://doi.org/10.1249/mss.0b013e3181c0647e
- Del Coso J, González-Millán C, Salinero JJ, et al. Effects of oral salt supplementation on physical performance during a half-ironman: A randomized controlled trial. Scandinavian Journal of Medicine and Science in Sports. 2015. https://doi.org/10.1111/sms.12427
- Cosgrove SD, Black KE. Sodium supplementation has no effect on endurance performance during a cycling time-trial in cool conditions: a randomised cross-over trial. Journal of the International Society of Sports Nutrition. 2013. https://doi.org/10.1186/1550-2783-10-30
- Ketelhut S, Moehle M, Hottenrott L. Effect of different sports drink compositions on endurance performance and substrate oxidation: a randomized, double-blind, placebo-controlled crossover study in trained athletes. Journal of the International Society of Sports Nutrition. 2025. https://doi.org/10.1080/15502783.2025.2516004
- Hoffman MD, Stuempfle KJ. Sodium Supplementation and Exercise-Associated Hyponatremia during Prolonged Exercise. Medicine and Science in Sports and Exercise. 2015. https://doi.org/10.1249/mss.0000000000000599
- He FJ, Li J, MacGregor GA. Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials. BMJ. 2013. https://doi.org/10.1136/bmj.f1325