Best Electrolytes for Runners
For runs under about an hour, most people do not need a mix. For long or hot runs, choose by milligrams of sodium, not by the flavor.
Quick Summary
For runs under about an hour, most runners do not need electrolytes beyond normal meals and water. For long runs, hot-weather runs, and races, choose by sodium per serving.
💡Key takeaways
- Whole-body sweat sodium is typically about 10–70 mmol/L, roughly 230–1,610 mg of sodium per liter of sweat (Baker, Sports Medicine 2017). In one large athlete dataset, predicted whole-body sweat sodium averaged 35.9 ± 10.4 mmol/L, about 825 mg/L (Baker et al., Journal of Sports Sciences 2016).
- Boston Marathon 2002: 13% of 488 finishers sampled had hyponatremia and 0.6% had critical hyponatremia. Substantial weight gain during the race was the strongest predictor (Almond et al., NEJM 2005). Too much plain water is the risk, not too little sodium alone.
- Milligrams per liter are Evident calculations: 1 mmol of sodium = 23 mg.
Six mixes, by sodium
| Feature | PH 1500 | LMNT | Skratch Sport | Tailwind | SaltStick | Nuun Sport |
|---|---|---|---|---|---|---|
| Sodium | 750 mg (1,500 mg/L in 500 ml) | 1,000 mg | 400 mg (370 mg in some flavors) | 303 mg | 430 mg | 300 mg |
| Carbs | Low-calorie | 0 g sugar | 19 g | Carb-based fuel | Low | 1 tablet |
| Price / serving | $1.62 | about $1.50 (brand site $1.13–$1.50) | $1.10 | $0.97 | $0.90 | $0.75 |
| Best for | Heavy or salty sweaters, hot races | Salty sweaters who fuel separately | Long runs where you want carbs too | Ultra and all-in-one fueling | Budget, moderate sweaters | Light top-ups, shorter hot runs |
Reviews: PH 1500, LMNT, Skratch, Tailwind, SaltStick, Nuun Sport. LMNT also lists 200 mg potassium and 60 mg magnesium per stick.
How much sodium per hour?
Runs under 60 minutes in mild weather: water to thirst is usually enough (ACSM position stand 2007).
Longer or hotter runs: use sodium-containing fluids. Size the sodium to your sweat. Salt-crusted kit or stinging eyes suggest higher losses.
Practice in training, not on race day. Do not drink so much that you gain weight during a race (NEJM 2005).
This is not medical advice. People with high blood pressure, kidney disease, or heart failure should ask their doctor before using high-sodium products. Illness rehydration is a different job from sport: see DripDrop ORS. All-sport context is on best electrolytes for athletes.
How we checked
On October 21, 2026, we checked the Baker sweat-sodium reviews, the 2005 Boston Marathon hyponatremia paper, the 2007 ACSM fluid-replacement stand, the LMNT and Skratch label pages, and the sodium and price figures already published on Evident electrolyte reviews. The prices in the table were checked that day. No affiliate links.
Frequently Asked Questions
For most runs under an hour, no. For long, hot, or race-day efforts, sodium replacement helps match sweat losses, which vary widely (Baker 2017).
One you have tested in training, with enough sodium for your sweat rate. Many marathoners use a carb-plus-sodium mix (Skratch, Tailwind) or a high-sodium mix (PH 1500, LMNT) alongside gels.
Typically about 230 to 1,610 mg per liter of sweat. Sweat rate also varies widely between people and conditions (Baker 2017). The milligram figures are Evident conversions: 1 mmol of sodium is 23 mg.
Yes. In the 2002 Boston Marathon study, 13% of 488 sampled finishers were hyponatremic, and 0.6% had critical hyponatremia. Weight gain during the race was the strongest predictor (Almond et al., NEJM 2005).
Tablets like Nuun Sport (300 mg sodium, from the Evident review) carry less sodium than high-sodium powders. Choose by milligrams of sodium, not by the format.
Sources
- Baker, Sports Medicine (2017), sweat rate and sweat sodium
- Baker et al., Journal of Sports Sciences (2016), sweat sodium dataset
- Almond et al., New England Journal of Medicine (2005), Boston Marathon hyponatremia
- ACSM position stand, Exercise and Fluid Replacement (2007)
- LMNT Recharge
- Skratch Labs Sport Hydration