Staying hydrated sounds simple in theory, but just one scroll of your TikTok feed on a hot summer day can quickly make you feel like you’re doing it all wrong. The water versus electrolytes conversation is, in a word, heated. Your head might swirl with questions: Should you be adding electrolytes to every bottle? Does coffee count toward your daily fluids? And is crystal-clear pee actually the goal? 

Here’s the reality: For most healthy adults, plain water is usually enough for a typical day, especially when they’re eating regular meals that provide electrolytes like sodium, potassium, and magnesium, notes Anne Danahy, M.S., R.D.N., an Arizona-based dietitian and founder of Craving Something Healthy. But there’s a reason electrolyte supplements exist. There are situations where adding them is the right call.

To clear up confusion, we asked experts when water alone gets the job done, when electrolytes are actually worth adding, and what to look for when buying a packet.

• ABOUT OUR EXPERTS: Anne Danahy, M.S., R.D.N., is an Arizona-based dietitian and founder of Craving Something Healthy. Dr. Sunjya Schweig, M.D., is an integrative family physician and founder of California Center for Functional Medicine. Dr. Michael Hall, M.D., M.Sc., is the founder of Hall Longevity Clinic. Jennifer Nicole Bianchini, M.S., R.D.N., is an integrative and functional registered dietitian, nervous system coach and founder of Body to Soul Health.

When Do You Need Electrolytes?

A short workout, a few errands, or an afternoon spent mostly in air-conditioning probably doesn’t call for electrolyte replacement. But once you’re sweating heavily (exercising for an hour or longer or spending hours in hot or humid weather) or losing fluids through vomiting or diarrhea, you’re no longer losing water alone. You’re losing electrolytes, too—most notably sodium.

That matters because sodium helps your body maintain fluid balance and hold on to the fluid you drink while also supporting blood volume, muscle function, and nerve signaling. 

There’s no single benchmark at which water suddenly stops working and electrolytes become essential. Still, experts say about an hour of sustained, sweaty activity is a useful starting point. “If you anticipate being out in the heat for long periods or exercising intensely—even in cooler weather—for an hour or more, it’s a good idea to hydrate with an electrolyte beverage before, during, and after,” says Danahy.

You may need electrolytes sooner if you’re working out in heat or humidity, sweating through your clothes, or leaving behind those chalky salt streaks on your skin or gear, says Dr. Sunjya Schweig, M.D., integrative family physician and founder of California Center for Functional Medicine. 

Read More: 5 Myths About Sweat—Busted

Other telltale signs you’re low on electrolytes include headaches, muscle cramps, dizziness, unusual fatigue, or being thirsty even though you’ve been drinking plenty of water. In those moments, your body may need sodium along with fluid.

Remember, too, that workouts aren’t the only activities that cause fluid and electrolyte losses. A marathon beach day, hours of yard work, a sauna session, an outdoor shift, or a stomach bug that causes vomiting or diarrhea can all drain more fluid (and sodium) than you might realize.

What To Look for in an Electrolyte Formula

As you consider electrolyte options, the first number worth checking is sodium. “Sodium is the main electrolyte lost in sweat and the most important mineral for maintaining fluid balance during heavy sweating,” says Dr. Michael Hall, M.D., M.Sc., founder of Hall Longevity Clinic. Yet some products marketed as serious hydration support contain only trace amounts.

For a legitimately sweaty workout or hot outdoor day, most experts we spoke with pointed to roughly 300-700 milligrams of sodium per serving as a practical range. Endurance athletes and particularly salty or heavy sweaters may need more, but there’s no universal magic number.

Schweig points out that potassium and magnesium can also be useful add-ins, but neither needs to dominate the label. “About 100-250 milligrams of potassium and 25-100 milligrams of magnesium may be plenty in a hydration formula,” he says, adding that higher doses of magnesium can cause loose stools in some people.

Sugar content is worth considering as well. During long or intense workouts, sugar’s simple carbohydrates can help sustain performance and support fluid absorption, Schweig explains. But for lighter activities, a sugar-heavy sports drink isn’t necessary. In those cases, a low- or no-sugar option may make more sense.

Can You Overdo Electrolytes—or Plain Water?

More hydration support isn’t always better hydration, according to Hall. The goal is to match electrolyte content and fluid volume to what your body is actually losing.

Using high-sodium electrolyte supps when you’re not sweating heavily from exercise or heat may lead to far more sodium than you actually need. This is especially true if your diet is already high in packaged or restaurant food, Hall explains. In general, a daily limit of 2,300 milligrams of sodium is best. If you’re not sure how much sodium you’re getting on the daily, a food tracker can give you a handy estimate.

Another important note: People with kidney disease, heart failure, uncontrolled high blood pressure, or medications that affect fluid balance should check with their health care provider before routinely using high-sodium electrolyte products, warns Schweig.

On the flip side, drinking way more fluid than your body needs can also be dangerous. (Yep, there’s actually a limit to how much water is good for you.) In rare cases, overdoing it on fluids can “water down” the sodium in your blood, causing it to drop too low, a condition called hyponatremia. Symptoms of hyponatremia can include nausea, vomiting, headache, confusion, and muscle weakness.

How Coffee and Alcohol Factor In

Despite its reputation, your morning coffee doesn’t automatically leave you dehydrated. Caffeine has a mild diuretic effect, but moderate amounts (i.e. 1-3 cups a day) still contribute to your overall fluid intake.

Alcohol, on the other hand, is way more dehydrating. It can make you lose more fluid because it blocks vasopressin, a hormone that normally helps your body hold on to water. One drink won’t automatically dehydrate you, but the effect can add up when you’re having several drinks, especially in the sun, heat, or while sweating, like during a long beach day, warns Jennifer Nicole Bianchini, M.S., R.D.N., an integrative and functional registered dietitian, nervous system coach and founder of Body to Soul Health. 

For every alcoholic drink, she recommends drinking one to two cups of water. Electrolytes aren’t automatically necessary just because alcohol is involved, though. They may make more sense if you’re also sweating heavily or losing a significant amount of fluid.

Hydration Mistakes To Avoid

One of the biggest mistakes is waiting until you feel totally parched, then trying to make up for it by chugging a huge amount of water at once. On hot or active days, Danahy says it’s better to drink regularly throughout the day and have some water before heading outside. Dark urine, infrequent bathroom trips, headache, dizziness and fatigue can all signal that you need more fluids.

Read More: Are You Making These Common Hydration Mistakes?

Then there’s the belief that completely clear urine is the ultimate sign of hydration. In fact, Schweig points out that constantly colorless urine may actually mean you’re drinking more than you need. “Pale yellow is generally a more practical target, though supplements, medications, and foods can also affect urine color,” he says.

Finally, don’t forget that hydration comes from food, too. “Fruits, vegetables, soups, yogurt, smoothies, beans, and cooked grains all provide water and minerals,” Schweig says. “A person eating regular meals may need less from a drink mix than someone exercising hard while under-fueled.”

The Bottom Line

Keep it simple: Water for everyday hydration; electrolytes for prolonged, heavy sweating or significant fluid loss. Schweig recommends sticking with water for shorter, lighter activities and normal days and adding electrolytes when you’re sweating heavily, exercising for around an hour or longer, spending several hours in the heat, or losing fluids through illness.

When you do reach for a formula, look at the sodium content first, and remember that neither more water nor more electrolytes is automatically better. The goal is to replace what your body is actually losing.