Electrolyte supplements are experiencing a boom.

Endurance athletes have been taking them during workouts and races for decades, but recently, they’ve become popular with everyone—from Crossfitters to tennis champions to couch potatoes. 

You can buy custom electrolyte supplements, blood tests to measure your electrolyte levels, and myriad hydration drinks, chews, pills, powders, and gels that promise to keep your blood brimful of electrolytes.

Why the clamor for these salty supplements?

According to the companies peddling these products, when you sweat, you lose large amounts of electrolytes like sodium, potassium, and magnesium. If you don’t replenish these vital minerals, you quickly become dehydrated, and your performance, mood, and overall health withers. 

Is this true, though? 

Are electrolytes the keystone of health and performance they’re puffed up to be?

And do you really need to refresh your electrolyte levels with special supplements, or can you get everything you need from food? 

Keep reading to learn what science says.

What Are Electrolyte Supplements?

The scientific definition of an electrolyte is a compound which produces positive or negative ions when dissolved in a liquid, like water. 

When it comes to nutrition, the term electrolyte refers specifically to a handful of minerals (the main ones being sodium, potassium, magnesium, phosphate, chloride, calcium, and bicarbonate) that when dissolved in bodily fluids create electrically charged ions.

These compounds create an internal environment that’s conducive to many bodily functions, including muscle contraction, nerve function, tissue repair, hydration, and nutrient absorption. 

An electrolyte supplement is simply a product that contains a mix of electrolytes, typically sodium, with small amounts of potassium and magnesium. Most electrolyte supplements come in a powder that you mix with water and then drink, but you can also buy them in ready-to-drink forms as well as tablets or capsules, and bars, gels, and chews. 

Some of the most popular electrolyte supplements include Gatorade, Powerade, Nuun, Pedialyte, LMNT, Jelly Belly Sport Beans, ONNIT HYDRATech, Ultima Replenisher, Liquid I.V., and Propel, and it’s become a cliché for pro athletes to release their own brand of electrolyte drink. Most of these products also contain carbohydrates and amino acids, but all of them underline electrolytes in their marketing.

You can also find many electrolyte supplements marketed as hydration supplements, as it’s claimed that supplementing with electrolytes is essential to staying hydrated (more on this in a moment). 

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Why Do People Take Electrolyte Supplements?

Most people take electrolyte supplements to stay hydrated, especially when working out in hot, humid environments. 

If you don’t take extra electrolytes, supplement companies claim, your body’s store of electrolytes will quickly dwindle, leading to reduced performance, brain fog, fatigue, muscle cramps, and eventually heatstroke, fainting, and even death.

As you can imagine, this has made electrolyte supplements a hobbyhorse among athletes, especially endurance athletes, who often do intense workouts and competitions in hot environments. 

For instance, it’s common to see triathletes, cyclists, runners, and tennis, basketball, football, and soccer players sipping electrolyte drinks during workouts and competitions and rhapsodizing about their benefits on social media. 

Research shows that this boosterism of electrolyte supplements works too. One study conducted by scientists at Loyola University Medical Center found that 58% of the runners sampled said that they drank sports drinks that contained electrolytes to prevent sagging blood sodium levels.

Why Electrolyte Supplements Are a Waste of Money

Electrolyte supplements are cut from the same cloth as BCAAs (“branch-chained amino acids”)—tasty water that doesn’t deliver on any of their “science-based” promises. 

The truth is that electrolyte supplements have been extensively studied, and most research shows that they’re no better than drinking plain water: they don’t improve performance, don’t prevent muscle cramps, and don’t help you stay hydrated. 

Instead, they give you a tiny dose of minerals that you could easily get from food for a fraction of the price. 

Let’s look at the scientific evidence to learn why.

Electrolyte supplements don’t improve performance.

The number one reason people drink electrolyte supplements is to improve their athletic performance, or, more specifically, to ward off the (purported) drop in performance that occurs when you hemorrhage electrolytes during exercise.

For example, Gatorade claims their Thirst Quencher beverage is “. . . the most scientifically researched and game-tested way to replace the electrolytes you lose in sweat” and relies on a number of celebrity endorsements like LeBron James, Serena Williams, Tiger Woods, and Michael Jordan to affirm their product. 

This is the substance of most electrolyte supplement marketing: drink (or eat) our electrolytes, and you’ll be a better athlete. 

This entire argument hinges on the idea that you lose large amounts of electrolytes (especially sodium) when you sweat, and that this loss of electrolytes leads to poor performance. While you also lose small amounts of potassium, magnesium, and other minerals during exercise, sodium is the main one, and thus often used in studies as a proxy for overall electrolyte losses.

According to supplement companies, electrolyte loss particularly harms “salty sweaters”—people who supposedly lose much more sodium and other electrolytes through sweat than average.  

If you look at the actual science, though, you’ll see this claim is smoke and mirrors. 

Even with no science-based, standardized definition of what a “salty” sweater is, this condition still isn’t enough to warrant supplementation. As exercise physiologist Ross Tucker explains in a series of excellent articles on his website, even the “saltiest” of sweaters only lose a small amount of electrolytes when they perspire. 

In fact, sweat has a much lower concentration of electrolytes than your blood. (In science jargon, your sweat is hypotonic, or less salty, than your blood.) Specifically, your blood contains about 140 millimoles (mM) of sodium per liter, whereas sweat contains closer to 20-to-60 mM/L. When you sweat, the concentration of electrolytes in your body actually rises, because you lose much more water than sodium, potassium, and other electrolytes. 

What’s more, the low concentration of electrolytes in drinks like Gatorade, Powerade, Cytomax, and so forth barely moves the needle in changing your body’s electrolyte chemistry. For instance, if a runner loses about two liters of sweat during a two-hour run and only drinks one liter of water, he’ll lose about 4.6 grams of sodium (that’s assuming he’s a “salty sweater,” by the way). If he instead downs a sports drink, he’ll still lose about 4.2 grams of sodium—too insignificant a difference to change his blood sodium levels or to affect his performance. (You could get the same amount of sodium by sprinkling ⅙ teaspoon of regular table salt on your food).

This lack of impact was demonstrated in a study conducted at Pennsylvania State University. Scientists showed that people who drank water or Gatorade during runs wound up with the same blood concentrations of sodium afterward. In other words, while you do lose some electrolytes in your sweat, the amounts are too small to matter, and are easily replenished over the course of the day from eating normal foods. 

This is true even during extreme endurance exercise, as demonstrated in a study on Ironman triathletes at the University of Cape Town. In this study, the scientists divided 413 triathletes competing in the 2001 Cape Town Ironman into three groups: an electrolyte group that consumed salt tablets, a placebo group that consumed starch tablets, and a control group that didn’t consume any special supplements. 

Each salt tablet contained 620 mg of table salt (sodium chloride), and the athletes were encouraged to consume 1-to-4 tablets per hour. On average, they ended up downing about 3.6 grams of pure sodium during the race (sodium chloride is about 40% sodium, so the runners ate an average of 9 salt tablets during the race).

The result? 

All three groups’ blood levels of sodium were within the normal, healthy range—taking electrolyte supplements made absolutely no difference. The scientists concluded that “. . . sodium supplementation was not necessary [emphasis mine] to preserve serum sodium concentrations in athletes competing for about 12 hours in an Ironman triathlon.”

(And in case you’re wondering, on March 19, 2001 when the race took place, the temperature was about 65-to-85 ℉ most of the day. These folks lost several gallons of sweat apiece, and still didn’t need salt tablets to keep their electrolyte levels topped off.)

Further bolstering these findings, a study published in 2018 in The International Journal of Sports Science reviewed five studies on the effects of sodium supplementation on endurance performance and concluded that “there is minimal evidence to draw a link between sodium ingestion and endurance performance.” In other words, most studies found no benefit to taking sodium supplements.

Some salty (sorry, couldn’t resist) electrolyte zealots sniff at these studies and claim that you have to consume much larger amounts of sodium to see benefits (and other electrolytes too), but this is daft for two reasons:

  1. First, most studies (including the one on Ironman triathletes) have found that people who don’t consume electrolyte supplements still have healthy, normal levels of electrolytes in their blood, and there’s no evidence that goosing them further would improve performance. 
  2. Second, even if you could choke down large amounts of salt during exercise, it wouldn’t necessarily be absorbed and could lead to other problems.

As exercise physiologist and nutrition scientist Dr. Stacy Sims has pointed out, when you consume lots of salt, this can “pull” water out of your bloodstream and into your intestines as your body tries to dilute the salt concentration in your digestive system (a process known as reverse water flux). 

While this isn’t a big deal at rest (go ahead and enjoy that pizza), it can lead to bloating, sloshing, and stomach cramps while working out. And again—it’s unnecessary. Consuming that much salt while training doesn’t offer any benefits over drinking water.

The bottom line? Electrolyte supplements are a busted flush when it comes to improving performance. 

Your body is extremely adept at regulating its sodium and electrolyte levels during exercise by controlling your thirst, and you don’t lose enough salt, potassium or any other electrolyte during exercise to benefit from supplementation. 

Electrolyte supplements don’t prevent muscle cramps.

Another oft-touted claim is that you can prevent or cure muscle cramps by swigging electrolyte supplements before, during, and after training. 

Supposedly, a loss of electrolytes disrupts muscular signaling in such a way that your nerves “short circuit,” leading to workout-killing charley horses. Like a car running low on oil, when your electrolyte levels peter out, the machine grinds to a halt.

Artful marketing, but also piffle. 

Scientists still aren’t sure about what exactly causes muscle cramps, but research has shown time after time that electrolyte depletion isn’t the culprit. 

One particularly illuminating study conducted by scientists at the University of Cape Town measured the electrolyte levels and incidence of muscle cramps in 72 runners in the Two Oceans Ultramarathon, a 35-mile foot race that snakes around the mountains of southern Africa. Forty-five of the runners also had a history of muscle cramps while running.

Unlike many studies, which only measured sodium levels, these researchers subjected the runners to a bevy of blood tests before, immediately after, and 60 minutes after the race. They measured the runners’ levels of sodium, potassium, calcium, and magnesium, as well as various markers of hydration such as blood, plasma, and red blood cell volume, and blood osmolality.  

The result? 

The researchers found no relationship between the runner’s electrolyte levels and their incidence or severity of cramping. In other words, people who experienced frequent, severe muscle cramps during the race were no more likely to have low electrolyte levels than people who didn’t cramp. They also found no association between cramping and dehydration.

One recent scientific review conducted by scientists at the Shanghai Research Institute even suggested that high levels of electrolytes could catalyze muscle cramps. The researchers speculated that since dehydration typically causes plasma electrolyte levels to rise, this could muddle nerve signals related to muscular contraction, leading to cramps. This is still just a theory, however, and most studies have found zero association between cramping and electrolyte levels, whether high or low.

So, if having low electrolyte levels doesn’t cause cramps, what does? 

Scientists haven’t found a smoking gun, but one of the strongest current theories is that cramps are the result of “altered neuromuscular control.” Basically, there’s a disruption in the electrical signals that cause muscles to contract, which makes them contract too long and at the wrong times. 

It’s not clear what causes this pesky phenomenon, but the most plausible theories include racing at a higher intensity than you’ve trained for (pushing yourself much harder than normal), training in conditions you aren’t accustomed to (such as very hot, humid weather), or not eating enough carbs before or during exercising (muscle glycogen depletion)—basically, inadequate preparation for the demands of the sport.

Probe around online and you’ll find many people who try to poke holes in this research, but dig into the details, and you’ll find they all boil down to stories:

“My friend’s wife, who’s a doctor and a triathlete, says she always takes electrolytes while training . . .” 

“[insert social media influencer here] swears by [insert low cost, high-margin electrolyte supplement]. You think you know better than him/her?”

“I don’t care what the science says—I haven’t had a single cramp since I started taking electrolyte supplements.” 

If you’re swayed by these arguments, then by all means take a flyer on electrolyte supplements. Just know that science says they’re no better than water, and that you’ll probably have better luck beating off cramps by improving your training, not slurping salty sports drinks.

Electrolyte supplements don’t help you stay hydrated.

In a clever sleight of hand, many supplement companies have tried to redefine dehydration as a loss of fluid and electrolytes. This is why you’ll often see electrolyte supplements branded as hydration supplements, as if they were equivalent.

We can start to unravel this facile line of reasoning by flipping open The Oxford English Dictionary, which defines dehydration as “the loss or removal of water from something” and “a harmful reduction in the amount of water in the body.” 

Notice how the word “electrolyte” doesn’t appear anywhere?

Semantic arguments aside, electrolytes do play a role in maintaining proper hydration levels, but your body has no trouble maintaining adequate electrolyte levels without supplementation, even during 12+-hour-long workouts in the heat.

Some electrolyte hucksters will counter that although electrolytes don’t directly help you stay hydrated, they indirectly help by encouraging you to drink more fluid. They usually follow this by reciting the well-worn and erroneous statistic that losing even 1-to-2% of your body weight (a proxy for body water) can reduce your athletic performance by 10% or more.

Thus, if even mild dehydration banjaxes your performance . . . and drinking more helps you avoid dehydration . . . and electrolyte supplements help you drink more . . . then electrolyte supplements help you avoid dehydration . . . or so the fallacy goes. 

Once again, this syllogism is sophistry.

The first part of this argument is true—most people naturally drink more of a salty electrolyte drink than plain water when given the choice—but this isn’t desirable.

After years of being bombarded with marketing messages about the importance of hydration, many athletes have developed a monomaniacal focus on drinking as much water as possible. You’ll often hear people say that you have to “Drink big,” or that you should “Drink before you get thirsty—by that time it’s too late!,” or “Drink enough that you don’t lose any body weight by the end of your workout.” 

Not only is this hand-wringing over hydration unnecessary, it decreases performance and is potentially dangerous.

Studies have repeatedly shown that mild dehydration—usually around 1-to-5%—doesn’t impair performance in runners, cyclists, and other athletes in balmy, hot, or humid conditions, and that forcing yourself to drink more than required to quench your thirst doesn’t improve performance and may even decrease it. 

The fastest athletes also tend to be the most dehydrated at the end of races. One of the most extreme examples of this is the runner Haile Gebrselassie, who lost 9.8% of his body weight in the course of winning the 2009 Dubai Marathon in a time of 2:05:29. 

The bottom line is that humans are perfectly capable of losing moderate amounts of fluid while racing and training, and have no problem rehydrating later in the day by simply “drinking to thirst.”

Guzzling excessive amounts of fluid—with or without electrolytes—can also quickly dilute the electrolyte concentration of your blood, leading to a condition known as exercise-associated hyponatremia (EAH), aka water intoxication

This condition kills far more people than dehydration, and is also harder to rectify once it sets in. The best way to avoid this is to drink to thirst, which will usually lead to a small, harmless degree of dehydration by the end of your workout or race that will naturally resolve itself throughout the day. 

There’s much more that could be said about the problems of overhydration, but in the final analysis, the data shows two things: 

  1. You don’t need electrolyte supplements or beverages to hydrate—plain water is fine. 
  2. You don’t need to make yourself drink more than your thirst dictates. In fact, doing so could impair your performance and endanger your health if taken to extremes.

They’re cheap, aggressively marketed, and taste good. 

That’s it. 

Electrolyte supplements are really just powders or pills containing inexpensive minerals that you can easily get from food, usually mixed with some flavors, sweeteners, and dyes, and wrapped in glittery packaging.  

This includes Gatorade and just about every other sports drink you can think of, as well as all of the gimcrack hydration supplements that are omnipresent at endurance competitions, in gyms, and online. 

Now, none of this is to say that hydration supplements are bad for you. While they can cause some problems with gastric discomfort and overhydration, this is generally only an issue when you consume a lot of them during a long workout or race. Sipping some electrolyte drink between sets in the gym isn’t a big deal.

But it’s not doing anything for you, either—it’s still just tasty, expensive water.

+ Scientific References