Quick answer
- These products are not competitors so much as different tools.
- LMNT delivers about 1,000 mg of sodium and no carbohydrate per stick, which suits heavy sweaters, hot weather, and pre-race sodium loading, but provides no fuel.
- Liquid I.V. sits around 500 mg of sodium with roughly 11 g of sugar, aimed at everyday rehydration rather than racing.
- Nuun Sport is about 300 mg of sodium with almost no carbohydrate, best as a light, low-calorie option for shorter runs.
- Gatorade Endurance carries about 300 mg of sodium and 14 g of carbohydrate per 12 oz, making it the only one of the four designed to fuel and hydrate at once, which is why it is on so many marathon courses.
- Match the product to your sweat sodium losses and to whether the drink also has to carry fuel.
5 key facts
- Sweat sodium concentration varies roughly four-fold between individuals, from about 200 to over 2,000 mg per litre, so no single product is correct for everyone.
- Sodium replacement matters most when a session runs beyond about 90 minutes, in heat, or when a runner is a visibly salty sweater.
- Drinking to thirst prevents both dehydration and the far more dangerous exercise-associated hyponatremia in most recreational runners.
- A high-sodium, zero-carb product used during a long run leaves a fuelling hole that gels must then fill.
- Cost per gram of sodium varies by more than five-fold across these products, and plain table salt is cheaper than all of them.
The electrolyte aisle has become genuinely confusing, and most comparisons make it worse by scoring products against each other as if they were trying to do the same job. They are not. One of these is a salt delivery system. One is a consumer rehydration drink. One is a low-calorie tablet. One is a race fuel. Ranking them head to head is like ranking a hammer against a screwdriver.
So this comparison starts from the numbers on the back of the packet, then works out which shape of product fits which kind of run. At the end you will find a sweat-rate calculator, because the single most useful thing you can know here is your own hourly fluid loss, not anyone else’s product review.
The numbers, side by side
Figures are per standard serving as published at the time of writing. Formulations change, so check your own packet before racing on these numbers.
LMNT (1 stick)
Sodium~1,000 mg
Potassium~200 mg
Carbohydrate0 g
Designed forHeavy sweaters, heat, low-carb diets, pre-race loading
Liquid I.V. Hydration Multiplier (1 stick)
Sodium~500 mg
Potassium~370 mg
Carbohydrate~11 g sugar
Designed forEveryday rehydration, travel, mild sessions
Nuun Sport (1 tablet)
Sodium~300 mg
Potassium~150 mg
Carbohydrate~1 g
Designed forLight, low-calorie hydration on shorter runs
Gatorade Endurance (12 fl oz)
Sodium~300 mg
Potassium~140 mg
Carbohydrate~14 g
Designed forFuel plus fluid during racing; common on courses
Skratch Labs Sport Hydration (1 serving)
Sodium~380 mg
Potassium~39 mg
Carbohydrate~21 g
Designed forModerate fuel plus fluid, real-fruit flavouring
Precision Fuel & Hydration PH 1500 (per litre)
Sodium~1,500 mg
Potassiumlow
Carbohydrate0 g
Designed forVery salty sweaters, extreme heat, long events
| Product | Sodium | Potassium | Carbohydrate | Designed for |
|---|---|---|---|---|
| LMNT (1 stick) | ~1,000 mg | ~200 mg | 0 g | Heavy sweaters, heat, low-carb diets, pre-race loading |
| Liquid I.V. Hydration Multiplier (1 stick) | ~500 mg | ~370 mg | ~11 g sugar | Everyday rehydration, travel, mild sessions |
| Nuun Sport (1 tablet) | ~300 mg | ~150 mg | ~1 g | Light, low-calorie hydration on shorter runs |
| Gatorade Endurance (12 fl oz) | ~300 mg | ~140 mg | ~14 g | Fuel plus fluid during racing; common on courses |
| Skratch Labs Sport Hydration (1 serving) | ~380 mg | ~39 mg | ~21 g | Moderate fuel plus fluid, real-fruit flavouring |
| Precision Fuel & Hydration PH 1500 (per litre) | ~1,500 mg | low | 0 g | Very salty sweaters, extreme heat, long events |
Read that table as two separate axes rather than one ranking. The first axis is sodium density: Nuun and Gatorade Endurance sit low, Liquid I.V. in the middle, LMNT high, PH 1500 very high. The second axis is fuel: LMNT, Nuun and PH 1500 carry effectively none, Liquid I.V. carries a modest amount, Gatorade Endurance and Skratch carry real carbohydrate. Where you land on both axes is decided by your sweat, the weather, and the length of the session.
How much sodium do you actually lose?
This is the question the entire category dances around, because the honest answer is that it varies enormously between people. Published sweat sodium concentrations in athletes span roughly 200 to over 2,000 mg per litre. Two runners side by side in the same race, at the same pace, can differ four-fold in what they need to replace.
Sweat rate itself typically falls between 0.5 and 2.0 litres per hour, and it climbs with heat, humidity, intensity, and body size. So a light sweater with dilute sweat might lose 150 mg of sodium per hour, while a large, salty sweater in humid heat can lose over 3,000 mg per hour. There is no product that is correct for both.
- White crusty residue on your skin, cap, or race kit after a run is a reasonable field sign of high sweat sodium.
- A history of muscle cramping late in long events, especially in heat, is weakly associated with high sodium losses, though cramping has several causes.
- Persistent salt cravings during and after long runs are worth taking seriously.
- If none of those apply and your runs are under about 75 minutes in temperate weather, plain water plus normal meals is genuinely sufficient.
Calculate your sweat rate
Use measurements from one representative workout. The formula accounts for drinks and any urine passed during the test.
A sweat-rate estimate is a planning input, not an instruction to replace every milliliter while moving. Avoid drinking enough to gain weight during exercise, and seek qualified medical advice for a history of hyponatremia, kidney or heart conditions, or heat illness.
Which one for which run
Easy run under 60 min, mild weather
What the drink has to doNothing. Water is fine
Sensible choiceWater; a tablet only if you enjoy it
60 to 90 min, warm
What the drink has to doModest sodium, little or no fuel
Sensible choiceNuun Sport or a half-strength LMNT
Long run 90 min to 3 h
What the drink has to doFuel and fluid together
Sensible choiceGatorade Endurance or Skratch, plus gels as needed
Long run in real heat
What the drink has to doHigh sodium plus separate fuel
Sensible choiceLMNT for sodium, gels or a separate carb drink for fuel
Marathon race day
What the drink has to doMatch the course product where possible
Sensible choiceWhatever is on course, rehearsed in training
Pre-race sodium load, 60 to 90 min before
What the drink has to doConcentrated sodium, minimal volume
Sensible choiceLMNT or PH 1500
Post-run rehydration after a sweaty session
What the drink has to doFluid plus sodium to retain it
Sensible choiceLiquid I.V. or LMNT with a normal meal
Everyday hydration, no training
What the drink has to doAlmost nothing
Sensible choiceWater and food; these products are unnecessary
| Session | What the drink has to do | Sensible choice |
|---|---|---|
| Easy run under 60 min, mild weather | Nothing. Water is fine | Water; a tablet only if you enjoy it |
| 60 to 90 min, warm | Modest sodium, little or no fuel | Nuun Sport or a half-strength LMNT |
| Long run 90 min to 3 h | Fuel and fluid together | Gatorade Endurance or Skratch, plus gels as needed |
| Long run in real heat | High sodium plus separate fuel | LMNT for sodium, gels or a separate carb drink for fuel |
| Marathon race day | Match the course product where possible | Whatever is on course, rehearsed in training |
| Pre-race sodium load, 60 to 90 min before | Concentrated sodium, minimal volume | LMNT or PH 1500 |
| Post-run rehydration after a sweaty session | Fluid plus sodium to retain it | Liquid I.V. or LMNT with a normal meal |
| Everyday hydration, no training | Almost nothing | Water and food; these products are unnecessary |
The most common mistake in this category is using a zero-carbohydrate high-sodium product as the sole drink on a three-hour long run, then wondering why the last 30 minutes fell apart. LMNT is excellent at the job it does. It does not contain fuel, and the run still needs 60 to 90 g of carbohydrate per hour once you go long.
The case against overdoing it
Electrolyte marketing has drifted a long way ahead of the evidence, and it is worth stating the other side clearly. The dangerous fluid error in endurance running is not usually dehydration, it is over-drinking. Exercise-associated hyponatremia occurs when runners take on more fluid than they lose and dilute their blood sodium, and it has caused deaths at major marathons. It is more common in slower finishers, smaller runners, and anyone following a rigid "drink on schedule" plan.
Consensus guidance from the sports-medicine community is to drink according to thirst rather than to a fixed timetable, and to use sodium to support fluid retention rather than as a performance drug in its own right. An electrolyte product does not make over-drinking safe.
- Do not force fluid on schedule during a long race; thirst is a good regulator for most runners.
- Gaining weight during a long run or race is a warning sign, not good hydration.
- If you have high blood pressure or a medical reason to limit sodium, talk to your doctor before adding 1,000 mg per stick to your day.
- Very high sodium products taken casually all day, outside training, are unnecessary for most people.
What about cost?
Cost per serving hides a bigger spread in cost per gram of sodium. Single-serve sticks are the most expensive way to buy salt ever devised. That is a fair price for convenience, portability, flavour, and precise dosing, and it is worth paying on race day. It is much harder to justify for a daily habit.
The cheap version, well known among ultrarunners, is to mix your own: about a quarter teaspoon of table salt provides roughly 575 mg of sodium, and combined with a carbohydrate source and squash or juice for flavour it produces a serviceable sports drink for pennies. It tastes worse. It works. Most runners land somewhere sensible in the middle: homemade or bulk drink mix for training, branded products for races where nothing should be a surprise.
A simple decision rule
- Under 60 minutes in mild weather: water.
- 60 to 90 minutes: water, plus modest sodium if it is hot or you sweat heavily.
- Over 90 minutes: you need carbohydrate as well, so either pick a drink that carries it or plan gels alongside a low-carb electrolyte.
- Very hot, very long, or visibly salty sweat: raise sodium toward 700 to 1,200 mg per hour and rehearse it in training first.
- Race day: use what you have practised, and check what the course serves so the two do not stack unexpectedly.
Frequently asked questions
Is LMNT or Liquid I.V. better for runners?
They solve different problems. LMNT delivers about twice the sodium with no carbohydrate, which suits hot weather, heavy sweaters and pre-race sodium loading. Liquid I.V. has less sodium and about 11 g of sugar, which suits everyday rehydration and travel. Neither carries enough carbohydrate to fuel a long run on its own.
Is Nuun or Liquid I.V. better?
Nuun Sport is lighter: roughly 300 mg of sodium and almost no calories, good for short and moderate runs where you want fluid without sugar. Liquid I.V. has more sodium and real sugar, so it retains fluid better after a sweaty session but is closer to a soft drink in use.
How much sodium does a runner need per hour?
Anywhere from about 200 to over 1,500 mg per hour depending on sweat rate and sweat sodium concentration. Most runners in temperate conditions do well between 300 and 700 mg per hour on runs over 90 minutes. Test it in training rather than on race day.
Is Gatorade Endurance good for marathon running?
Yes, and its main advantage is availability: it is the on-course drink at many large marathons, so training with it removes race-day surprises. It carries roughly twice the sodium of standard Gatorade plus real carbohydrate, which is the right shape for a marathon.
Do I need electrolytes for a 5K or 10K?
Almost never. Sessions under about 60 minutes in mild weather do not deplete electrolytes meaningfully. Normal meals restore anything lost. Save the products for long runs, heat, and races.
Can you take too many electrolytes?
Yes. Very high sodium intakes cause gut discomfort, and no electrolyte product makes over-drinking safe. Exercise-associated hyponatremia comes from consuming more fluid than you lose, and it is a genuine medical emergency in endurance events. Drink to thirst rather than to a fixed schedule.
Sources
- 1American College of Sports Medicine Position Stand: Exercise and Fluid ReplacementMedicine and Science in Sports and Exercise (Sawka et al., 2007)Sweat rate ranges and fluid replacement principles
- 2Statement of the Third International Exercise-Associated Hyponatremia Consensus Development ConferenceClinical Journal of Sport Medicine (Hew-Butler et al., 2015)Drinking to thirst, and the risks of over-drinking during endurance events
- 3Variability of Sweat Sodium Concentration in AthletesSports Medicine (Baker, 2017)Why sodium replacement cannot be standardised across individuals
- 4Nutrition for Marathon Running: Consensus StatementWorld Athletics / IAAF Consensus (Burke et al., 2019)Carbohydrate and fluid guidance for marathon racing
General guidance for healthy adults, not medical advice. Talk to a doctor or registered dietitian if you have a health condition, take medicines or have special dietary needs.
