Published on 26 Oct 2026

Electrolytes: what they are, what they’re used for, and when to take them

What electrolytes are, in what situations it makes sense to replenish them, and when water and food are enough. With data from the EFSA, the WHO, and Spanish sports medicine.

Electrolytes are everywhere: on isotonic drink labels, in pharmacy sachets, and all over the gym. But it is rarely explained what they are, when you need to take them, and when water and food are more than enough. Here is the short, straightforward version, with data from the EFSA, the WHO, and Spanish sports medicine.

What are electrolytes?

Electrolytes are minerals that carry an electric charge when dissolved in the body's water. The main ones are sodium, potassium, chloride, calcium, magnesium, and bicarbonate. They are in the blood, inside and outside cells, and the body maintains them in a fairly delicate balance.

This balance allows water to be distributed properly between different compartments, nerves to transmit signals, and muscles to contract. That is why, when you lose a lot of fluid suddenly, you do not lose only water: minerals, especially sodium and chloride, are also lost through sweat.

Where do electrolytes come from in everyday life?

Basically, from food. Sodium comes from salt and processed foods; potassium, from fruit, vegetables, legumes, and nuts; calcium, from dairy and some vegetables. For most adults with a normal diet, the problem is not a lack of sodium but an excess: the AESAN reminds us that much more salt than recommended is consumed in Spain, and the WHO sets the target at less than 5 g of salt per day (about 2 g of sodium).

As for water, the EFSA sets the total adequate intake at around 2 liters per day for adult women and 2.5 liters for men, also counting the water that comes with food. If you exercise, it is hot, or you sweat a lot, the figure increases.

When does it make sense to take electrolytes?

These are the situations in which replenishing electrolytes in addition to water makes sense:

Long or intense workouts: when the effort lasts more than an hour, or is very demanding, you sweat a lot and lose sodium. The Spanish Federation of Sports Medicine recommends drinks that provide sodium, not just water, in these cases.
Heat and heavy sweating: summer, physical work, matches, or routes in the sun. If you end up with a white t-shirt covered in salt, that is a pretty clear sign.
After exertion: to recover what was lost, accompanying food and water.
When you find it hard to drink water alone: if a flavored, sugar-free drink helps you drink more throughout the day, it already does its job.

And a separate situation: if you have diarrhea or vomiting, what you need is an oral rehydration solution from the pharmacy, which has a specific composition for that, and to consult your doctor if it persists or there are signs of dehydration. No sports drink replaces an oral rehydration solution.

And when is it not necessary?

If you go to the office, study, or do a half-hour light workout, water and a normal diet are more than enough. There is no need to turn electrolytes into a default daily ritual. It is also not a good idea to take them in large quantities unnecessarily, and if you have high blood pressure, kidney problems, or follow a low-sodium or low-potassium diet, consult your doctor first.

Isotonic drink, oral rehydration solution, or sugar-free electrolytes: what is the difference?

Not everything that says "hydration" is the same. This table summarizes the main differences:

Type	What it is designed for	Sugar	To keep in mind
Oral rehydration solution	Diarrhea, vomiting, dehydration	Some glucose, in a fixed ratio	Pharmacy product, specific use
Classic isotonic drink	Long endurance sports	High, provides carbohydrates	Useful for efforts lasting several hours; in everyday life, it adds a lot of sugar
Sugar-free electrolytes (like Hydrize)	Hydrating yourself at the gym, in the heat, or during the day	0 g	Does not provide carbohydrates, so in very long events you may also need an energy source
Water alone	Everyday life	0 g	Enough in most normal situations

What does Hydrize contain?

Hydrize is our hydration line: a powder drink without caffeine, sugar, or carbonation, to drink at any time without worrying about sleep. It is prepared with a 6 g scoop in 500 ml of cold water, and each 180 g container brings 30 servings.

According to the Hydrize Fresh Shot (Watermelon) sheet, each 500 ml serving provides:

Potassium: 300 mg (15 % of the NRV).
Chloride: 158 mg (20 % of the NRV).
Calcium: 120 mg (15 % of the NRV).
Salt: 0.27 g.
Vitamins A, C, D, E, K, and B group, plus L-tyrosine, choline, and L-carnitine.
0 g of sugars and about 4 kcal, with sucralose as a sweetener.

Potassium contributes to the normal functioning of muscles, and calcium to normal muscle function. Beyond that, what we seek with Hydrize is something simple: to make drinking water appealing. There are three flavors available: Fresh Shot (watermelon), Citric Power (lemon), and NRGY Hypnos, with the flavor of traditional energy drinks but without caffeine.

If you are interested in the caffeine topic, you have more context in our guide to caffeine-free energy drinks, and if you train, in the comparison of pre-workout or energy drink.

How to take electrolytes so they are useful?

Before and during the workout: one glass before starting and sips during the session work better than drinking it all at once at the end.
With cold water: it is easier to drink, and the powder dissolves without a problem if you shake it in a shaker or a bottle with a lid.
Don't exceed the dose: one serving a day is the recommended dose of Hydrize. More is not better.
Don't forget the water: electrolytes accompany hydration, they do not replace it.

A useful sign to know if you are well hydrated is the color of your urine: light yellow is good; dark and scarce usually indicates that you lack fluid.

Frequently asked questions

Can I take electrolytes every day?

If you follow the indicated dose and do not have any medical condition that advises against it, yes. But on days without sports or heat, water and food are usually enough.

Do electrolytes contain caffeine?

Not by themselves. Some drinks combine them with caffeine, but Hydrize does not: it is Z Drinks' option to hydrate at any time, also in the afternoon or at night.

Do drinks with electrolytes make you gain weight?

It depends on the sugar. A classic isotonic drink can contain quite a few calories; Hydrize Fresh Shot has 0 g of sugars and about 4 kcal per serving.

Are electrolytes useful for gastroenteritis?

For diarrhea or vomiting, what is recommended is an oral rehydration solution from the pharmacy and to consult a doctor if it does not improve. A sports drink is not designed for that.