If running in the summer leaves you feeling drained and depleted for the rest of the day, like you just sweat out your last remaining brain cell, there’s a good chance you need to take in more electrolytes. Electrolytes are particles that conduct electricity in water, and they’re vital for normal human body function. Typically, it’s not hard to get enough electrolytes from our food, but when we’re sweating a lot during activity—particularly in hot weather, for longer than an hour—we can lose more than we’re taking in. For runners, common signs of an electrolyte imbalance include dizziness, nausea, cramping, and fatigue, though more serious consequences are possible in extreme cases.

The good news is that there are dozens of drink tablets designed to replenish lost electrolytes fast, so you’ll feel recharged after a run instead of headachy and lethargic. Some of them are even pretty tasty, making drinking plenty of water a little easier, as well. Below are quick hits on five electrolytes we love, plus what to know and what to buy. Or scroll deeper to read full reviews of these and others.

What You Need

The most common electrolytes lost in sweat during a run are sodium and chloride, with smaller losses of potassium, magnesium, and calcium, says sports nutritionist Leslie Bonci, MPH, RD, CSSD, RDN, and owner of Active Eating Advice. “Sodium losses can be up to 1,000 milligrams per hour, but can range from 200 milligrams to 12,500 milligrams,” she says. Sodium chloride (more commonly known as just salt) is important because it helps maintain fluid balance and nerve function, which controls your muscle contractions. Most electrolyte tablets pack anywhere from 200 to 800 milligrams of it to replace some of the salt you lose through sweat.

Low salt can lead to muscle cramps, but so too can low potassium. That’s why most electrolyte tablets include potassium to replace what you’ve lost through sweat and maintain fluid balance. The electrolyte mixes we tested here include anywhere from 38 to 400 milligrams of added potassium, though you can also meet your recommended daily amount of 4,700 milligrams through good food choices.

Calcium and magnesium—necessary to regulate muscle contractions and heart rhythm, maintain good bone health, and help muscles relax—are included in varying degrees in most electrolyte drinks, depending on the brand. Other ingredients that come into play are bicarbonates to delay fatigue, carbohydrates to maintain energy, and even occasionally caffeine for an added kick in the pants. Some, like Nuun Sport, have low calories, low carbs, and use Stevia as a sweetener for shorter runs. Others, like Skratch Sport, include 80 to 100 calories, and plenty of carbs and sugar for powering runs longer than an hour. Each brand has its own formula and recommended use; you might want to try a few before you figure out which works and tastes best for you.

When to Take Electrolytes

If you’re running for less than an hour, you can probably get what you need to stay hydrated from water alone, no need for an extra electrolyte drink. But if you’re running for more than an hour—or if, like me, you’re a salty sweater who ends workouts looking like a soft pretzel, with a layer of crust on your skin and clothes—you should pack an electrolyte tablet to drop into a bottle of water during or after a run. Not only will you better stay on top of your sodium losses, but it’s a more eco-friendly way to hydrate than buying a bottle of sports drink for every long run.

For those of us who run in the heat, being proactive with fluids, carbohydrate, sodium, and potassium before a run can also be helpful, says Bonci. But you’re not limited to electrolyte drinks—you can do that with a healthy diet, as well. “For instance, orange juice with salt added could be consumed before a run,” Bonci says. “During the run, an electrolyte drink would be advised, and after the run, replace fluid, carbs, sodium, potassium with food and beverages rather than an electrolyte supplement or beverage.” Whatever your hydration strategy, the important thing is that you drink fluids and replace lost salt so your muscles can perform their best.

How We Tested

We called in a pile of electrolyte tablets and mixes—some our staff uses regularly, others that are new to us—and used our own experience training in the ungodly Texas summer heat to determine the best. We evaluated them on taste, ingredients, effectiveness, tolerability, and value to come up with this list of best options to drop into a water bottle after your next hot run. Here are our standouts.


Nuun Sport/Endurance

Nuun Sport Hydration Tablets
Nuun nuunlife.com

  • Low in sugar
  • Subtle flavor
  • Compact tube

  • Some find it has a chemical taste

Nuun Sport is a great option for when you want electrolytes during or after a run without the sugar, calories, or cloying sweetness of traditional sports drinks like Gatorade. Just drop a fizzy Nuun tablet into 16 ounces of water and wait a few minutes. With 1g of sugar, 2g of carbs, and 15 calories—plus a mix of 300mg of sodium, 150mg of potassium to fight cramping, 13mg of calcium, and 25mg of magnesium—it will help you feel more hydrated and balanced post-workout. The flavors can be hit or miss (I prefer the basics like lemon-lime or grape), but most go down fairly easy after you’ve been sweating for an hour, provided you’re patient enough to let the tablet fully dissolve. Some flavors even include caffeine, if you’re looking for an extra mid-run kick—or even some light, pre-run hangover help (I have tested this many times). If you plan to run for 90 minutes or more, try Nuun Endurance mid-workout, which has 60 calories and 15g of sugar, plus even more sodium to keep you hydrated for longer efforts. Nuun also gets bonus points for being easy to find—if you don’t want to order online, you can buy it everywhere from your local running store (recommended!) to big-box giants like Target.


Skratch Labs Sport

Skratch Labs Sport - 20 Pack
Skratch Labs competitivecyclist.com

  • Natural taste
  • Great for long runs or rides

  • On the costly side

Thanks to real fruit flavor in its powder mix, Skratch Sport wins the award for best-tasting—or should we say “least chemical tasting”?—electrolyte drink we tested. A higher overall sugar volume (18g per 12- to 16-ounce serving) is inarguably also a factor, which is why I generally reserve Skratch’s tasty hydration magic for longer runs or bike rides. Skratch founder and sports physiologist Allen Lim designed the product to be as simple and natural as possible, with an ingredient list that’s noticeably shorter than that of most major electrolyte drinks. Still, the 80-calorie blend packs 20g of carbs, 380g of sodium, 43mg of calcium, and 38mg of potassium in an effort to match the ratio of electrolytes you lose while you sweat and replace the energy you’ve burned. After a two-hour bike ride on a 100+-degree morning, a scoop of Skratch mixed into cold water was the only thing catapulting me through the rest of my day and preventing that headachey slump that can strike after a hot workout. Had I been running two hours in that kind of heat, I could have reached for Skratch Hyper, which has more sodium than a bag of potato chips (1720mg!) to replace your sweat losses. For even more intense efforts, Scratch also makes a higher-calorie recovery mix in flavors like chocolate, coffee, and delicious horchata. You can order the stuff online or find it at a specialty running store.


Gatorade Gatorlytes

Gatorade Gatorlytes (Pack of 20)
Gatorade amazon.com

  • Ideal for long endurance events in hot weather
  • Flavorless on their own

  • Overkill for shorter runs

Gatorlytes have no flavor—unless you consider salt a flavor on its own, in which case Gatorlytes are a sodium-spangled five-course meal sourced from the depths of the Dead Sea. Designed specifically for cramp-prone endurance athletes, the electrolyte powder blend has zero calories and carbs on its own but is designed to be mixed into another sports drink. Drop it into water, and the 780mg of sodium will taste largely undrinkable unless you just finished a marathon in triple-digit heat. Mix a packet into a 20-ounce Gatorade, and it’s far more tolerable while delivering 1,060mg of sodium—which sounds like a shocking amount until you dig into sodium levels of common chain restaurant orders. Naturally the first ingredient in Gatorlytes is salt, but on its own it also has 400mg of potassium to fight cramps, plus 6 percent of your daily value of calcium and 10 percent of magnesium. If you’re a salty sweater and you tend to cramp while running in the heat, Gatorlytes might be just what you need to keep your electrolytes balanced and yourself moving. But for runs under 90 minutes, it feels like super-salty overkill—even for this heavy sweater. You can find Gatorlytes online or at specialty sports stores.


Science in Sport Go Hydro

Science in Sport Go Hydro - 20 Tablets
Science in Sport amazon.com

  • Low in calories
  • Mild, inoffensive taste

  • Not enough energy for longer runs

Originally created for the British Sailing team at the 2008 Beijing Olympics, Science in Sport Go Hydro is another low-calorie option for fast hydration before, during, or after a workout. Each tablet has 10 calories and offers similar benefits to other major electrolyte drinks, with 350mg of sodium, 65mg of potassium, 8mg of magnesium, and 102mg of calcium, among others. I popped a tablet into some water after a blazing-hot five-mile run (have I mentioned it’s summer in Austin?) and found the clean, mild taste to be agreeable and the sodium to be restorative. On a longer run, I would likely have preferred something with more carbs and calories, but this product was perfect for a quick re-up of electrolytes after 40 minutes of hard effort. It’s arguable whether you actually need an electrolyte drink for a run that short, but the light flavor made drinking plenty of water a little faster and easier, so I’ll count that as a summer hydration win.


Hammer Endurolytes Fizz

Hammer Endurolytes Fizz
Hammer runningwarehouse.com

  • Easily digested
  • Inexpensive
  • Low in calories for shorter runs

  • Taste is hit or miss

For a quick blend of sodium chloride, potassium, calcium, and magnesium, you can just pop Hammer’s Endurolytes capsules and wash them down with a bottle of water. But for those of us who feel attached to the idea of combining the two, Hammer makes these fizzy tablets that you can dissolve in water for before, during, or after a workout. The taste is mild, but vaguely chemical—possibly owing to the fact that these are sweetened by Stevia and have just seven calories and zero carbs. With 200mg of sodium, 100mg of calcium, 100mg of potassium, and 50mg of magnesium, among others, Endurolytes have a similar but slightly tweaked formula to other electrolyte tablets, like Nuun and Science in Sport Go Hydro. Ultimately I found that they did the job after an hour-long run, and helped me feel less drained in the heat. But they didn’t go down as easily as The SIS Go Hydro tablets and didn’t make me want to take in more water. You can find Hammer Endurolytes Fizz at your local running store or sports retailer.


GU Drink Tabs

Hydration Drink Tablets
GU rei.com

  • Plenty of sodium
  • Inexpensive
  • Compact tube

  • Flavor might be too strong for some

If you want a Stevia-sweetened, 10-calorie electrolyte tablet with a stronger taste than Nuun or SIS Go Hydro, GU drink tabs are your new go-to. They take a few extra minutes to dissolve in water, but once they’ve clouded up your bottle you’ll get more of a sense that you’re drinking a flavored beverage, as opposed to the vague hint of berry or citrus provided by other drink tabs. Whether that’s a good thing is up to individual preference—personally, I was surprised by how much I enjoyed the strawberry-lemon flavor in an ice-cold glass of water after an hour-long, 100-degree run, but I can see a hot-mid-run bottle of the stuff going down with far less ease. Each tab has 3 grams of carbs, 320 mg of sodium, 55mg of potassium. There’s no magnesium in them, but research suggests that we don’t lose nearly as much magnesium through sweat as we do sodium and potassium. If you know your stomach is easily irritated by the sugar alcohol sorbitol, this might also be the tab for you—GU drink tabs use the compound Xylitol as an alternative. They’re also just a good bargain—$6.50 will get you a tube with 12 tablets at REI.



Hydralyte Electrolyte Tablets
Hydralyte walmart.com

  • Easy to find
  • Easy to digest

  • Lower in sodium than some dedicated sports drinks

Hydralyte isn’t billed strictly as a sports drink—it would rather be known as an all-purpose electrolyte beverage clinically formulated to hydrate you when you’re sick, traveling, working out, or being exposed to excess heat. To that effect, it has something of a sick-day vibe that evokes flashbacks to childhood illnesses and adult hangovers. But that’s not to say it doesn’t work after running. Just drop two tablets into a small cup of water and wait for them to dissolve, then nurse the concoction. It tastes just fine—not unpalatable, but not something you’d want to drink for fun. With 20 calories, 280mg of sodium, 160mg of potassium, 5g carbs, and 4g of sugar, the nutritional information doesn’t veer far from more dedicated sports drinks, but the big advantage here is that you can often find it at grocery stores, pharmacies, and other outlets that might not carry any electrolyte drinks beyond Gatorade or Powerade. The brand also claims Hydralyte is more kid-friendly than traditional sports drinks, likely due to the mild taste and easy digestibility.


Osmo Active Hydration for Women

Osmo Active Hydration for Women
Osmo amazon.com

  • Research-backed formula for women
  • Good for long runs

  • Too sweet for some testers

Osmo makes its endurance sports-oriented Active Hydration powders in a regular formula and one that’s been optimized for women. The latter was developed by exercise physiologist and nutrition scientist Dr. Stacy Sims to “provide women with enhanced hydration throughout the menstrual cycle,” based on the astute reasoning that performance research has historically been based on data from only male subjects, and women have different needs. Ingredient-wise, this translates to 80 calories in the women’s formula compared to the regular’s 70, 290mg of sodium instead of 260mg, 18 grams of sugar and carbs instead of 17, slightly less calcium, more potassium, and a few other tweaks. Those numbers aren’t by accident—they’re the result of research on female endurance athletes showing that estrogen reduces the availability of carbohydrates, and elevated progesterone raises core temperature, which increases sodium losses and muscle breakdown. I tried both women’s and regular Osmo Active Hydration throughout a variety of workouts and found both products to be sweeter and stronger-flavored than other electrolyte drinks, and best suited to long runs or bike rides that demanded a lot of my body. Ultimately I chose the women’s version for its mango flavor, with the awareness that the formula likely skewed closer to my hydration needs for runs over 10 miles. You can find it online or through specialty bike shops and running stores.