Do you need electrolytes, or is water enough?

Are electrolytes good for you?

Electrolytes are essential, but extra electrolytes only help when you've lost more than food will put back. Sodium, potassium, chloride, magnesium and calcium are minerals that carry a small electrical charge in your body's fluids, and your body needs all of them.

Most people in the UK already get more sodium than they need. Adults in England eat about 8.4 g of salt a day on average, 40% above the 6 g maximum the government recommends, according to the 2018 to 2019 National Diet and Nutrition Survey. Most of it is already in food before you reach for the salt: Food Standards Scotland estimates that around 75% of the salt we eat comes from packaged foods such as bread, breakfast cereal and ready meals. Potassium comes from foods like bananas, broccoli, parsnips, beans, nuts, seeds, fish and meat. Sipped every day at a desk, an electrolyte drink mostly adds salt to a diet that already has plenty.

What are electrolytes, and what does each one do?

Electrolytes are minerals that carry an electrical charge when they dissolve in water or body fluids, and you take them in through food and drink. The main ones, with what the NHS and the US National Library of Medicine say about them, are:

• Sodium and chloride (together, salt) keep the fluid in your body balanced, and chloride also helps you digest food.
• Potassium helps control the balance of fluids in the body and helps the heart muscle work properly.
• Magnesium helps turn food into energy.
• Calcium helps build bones, keeps teeth healthy and helps regulate muscle contractions, including your heartbeat.
• Bicarbonate helps keep your body's acid-base (pH) balance and helps carbon dioxide move through your blood.

Levels shift when the water you take in and the water you lose don't match, which is why vomiting, diarrhoea and heavy sweating matter. Some medicines, including diuretics, and conditions such as kidney disease can disturb them too.

What are the best natural sources of electrolytes?

Ordinary food and drink supply all of them. The NHS lists these as good sources:

Among natural drinks, milk has some research behind it. In a 2016 trial, 72 healthy, fasted men drank 1 litre of water or one of 12 other drinks, and their urine was collected for the next four hours. They passed less urine after skimmed milk, full-fat milk or an oral rehydration solution than after water, while tea, coffee, orange juice, cola and a sports drink did not differ from water. It was a short trial at rest, so it says little about heavy sweating.

Is water enough?

For everyday life, yes. The NHS suggests 6 to 8 cups or glasses of fluid a day, and says water, lower-fat milk and lower-sugar drinks, including tea and coffee, all count. After sweating during physical activity, its advice is to drink extra, and it calls water the best way to replace lost fluids.

A gym class or a 5 km run rarely needs more than water, and your next meal will cover the salt most people lose in that time. For how much to drink in the first place, read how much water you need a day.

When do electrolytes actually help?

They help when you lose a lot of sweat over a long time, and, in a different form, when illness makes you lose fluid from the gut. Sweat is mostly water, but it carries sodium out with it, and the amount varies a great deal. A 2017 review of sweat testing in athletes found whole-body sweat typically contains about 10 to 70 mmol of sodium per litre (roughly 230 to 1,600 mg), with sweat rates mostly between 0.5 and 2 litres an hour, so two people on the same long run can lose very different amounts.

Long or hot exercise

The Australian Institute of Sport considers electrolyte supplements useful for exercise lasting more than an hour with large sweat losses or very salty sweat, ultra-endurance events of more than about four hours, and rehydrating after a session that has left you well short of fluid. It also says there is currently no consensus on the value of replacing sodium during exercise. The American College of Sports Medicine's fluid replacement position stand says drinks with electrolytes and carbohydrate can do better than water in some circumstances and, because sweat varies so much, recommends individual plans. You can estimate your own sweat rate by weighing yourself before and after a session.

Very hot weather

The NHS advises drinking more when you're sweating because of hot weather, which for most people means more water. Electrolytes are worth considering when you're working or exercising outdoors for hours and sweating heavily, because that's when sodium losses start to add up.

Vomiting or diarrhoea

If you're being sick or have diarrhoea and are losing a lot of fluid, the NHS says a pharmacist can recommend an oral rehydration solution: a powder you mix with water. These are licensed medicines made to a fixed recipe of glucose, sodium and potassium, because glucose and sodium are absorbed together from the gut and draw water in with them. Sports drinks and electrolyte sachets are designed around sweat, so they aren't a substitute. NHS advice is also to avoid fruit juice and fizzy drinks when you have diarrhoea, because they can make it worse. Call 111 if you still have signs of dehydration after using rehydration sachets, or if you keep being sick and can't keep fluids down.

Sickness and diarrhoea are listed by the NHS as common side effects of tirzepatide (Mounjaro). If that's you, our guide to eating well on GLP-1 medication covers food and fluids, and your pharmacist can advise on rehydration.

What's the difference between rehydration sachets and electrolyte sachets?

Rehydration sachets (oral rehydration salts) are medicines for fluid lost through sickness or diarrhoea, while electrolyte or hydration sachets are made to replace sweat. Both are powders you stir into water, but the recipes differ.

The World Health Organization's reduced-osmolarity oral rehydration solution has 75 mmol of sodium and 13.5 g of glucose in each litre (Suh and colleagues, 2010). In weight, 75 mmol of sodium is about 1.7 g, roughly two and a half to three and a half times the 0.5 to 0.7 g per litre suggested for drinks during exercise, with between a sixth and a third of the carbohydrate in a typical 4 to 8% sports drink.

A UK pharmacy sachet has its own recipe: 3.56 g of glucose, 0.47 g of sodium chloride, 0.30 g of potassium chloride and 0.53 g of disodium hydrogen citrate in 200 ml of water, and its leaflet says to use water only. In the 2016 trial above, the oral rehydration solution held on to more fluid than water did and the sports drink did not.

How much sodium is in an electrolyte drink, in salt terms?

Multiply the sodium figure by 2.5 to get salt, the method Food Standards Scotland gives for reading labels. So 1,000 mg of sodium is 2.5 g of salt, about 40% of the 6 g adult maximum.

Electrolyte sachets and hydration tablets vary a lot, so read the label per serving and compare it with what you're replacing. A litre of sweat contains somewhere between 230 and 1,600 mg of sodium, going by the review above. For drinks taken during endurance exercise, the Australian Institute of Sport suggests 0.5 to 0.7 g of sodium per litre of fluid, noting that saltier drinks taste worse and people tend to drink less of them.

Electrolyte powder, sachets, tablets or gummies: which should you choose?

They are the same idea in different packaging, so compare them on what the label says rather than on the format:

• Sodium per litre. Divide the sodium in one serving by the litres of water you mix it with. 300 mg of sodium in 500 ml is 600 mg a litre, inside the range above. The same 300 mg in 200 ml is 1,500 mg a litre, which is much saltier.
• Fixed or scooped. A sachet or tablet is a set amount, while powder from a tub depends on how level your scoop is.
• Sugar. Some mixes have none. Others carry carbohydrate at the 4 to 8% a sports drink typically has, so check the grams per serving against the NHS limit of 30 g of free sugars a day for adults.
• Gummies and chews. These contain no water, so how concentrated you end up depends on how much you drink with them. The NHS says sugar is one of the main causes of tooth decay, which is worth remembering if you have a sweet format often.

Should you choose sugar-free electrolytes or ones with carbohydrate?

Sugar-free electrolytes make sense for shorter sessions, for heat when you aren't exercising hard, or when you're watching your sugar intake. Carbohydrate is worth having in longer efforts, both as fuel and because it helps you absorb fluid.

On fuel, the Australian Institute of Sport describes sports drinks as typically 4 to 8% carbohydrate, and suggests 30 to 60 g of carbohydrate an hour for exercise lasting 1 to 2.5 hours, rising to up to 90 g an hour beyond about 2.5 to 3 hours. On absorption, glucose helps the gut take up sodium and water. In Great Britain, drinks with carbohydrate and sodium inside set limits are allowed to say that carbohydrate-electrolyte solutions "enhance the absorption of water during physical exercise". Sugar-free products can't carry that claim.

You can also pair a sugar-free electrolyte with carbohydrate from food, such as a banana or a gel. One downside of sugary sports drinks is teeth: the Australian Institute of Sport warns they can cause erosion and suggests limiting how long the drink sits on your teeth.

Can you make a homemade electrolyte drink?

For exercise, yes, if you accept that it's approximate. A simple version: 500 ml of fruit juice, 500 ml of water and a quarter of a level teaspoon of salt. The NHS says 6 g of salt is about one level teaspoon, so a quarter teaspoon is roughly 1.5 g of salt, or about 600 mg of sodium in the litre. That sits inside the 0.5 to 0.7 g per litre range above. If your juice has about 10 g of sugar per 100 ml (check the carton), the mix comes out near 5 g per 100 ml, inside the usual sports drink range.

Some caveats:

• Kitchen spoons are imprecise, and too much salt makes the drink unpleasant and can upset your stomach.
• Don't use it for vomiting or diarrhoea. Fruit juice can make diarrhoea worse, and oral rehydration solution from a pharmacist is made for that job.
• If you've been told to limit salt, this counts toward your total like any other salty drink.

Who should be careful with electrolyte drinks?

If a doctor manages your salt, potassium or fluid intake, check before using them. That includes:

• People with high blood pressure. Eating too much salt can cause high blood pressure, and one 1,000 mg sodium sachet is 2.5 g of salt.
• People with chronic kidney disease. NHS advice includes keeping salt under 6 g a day and avoiding potassium supplements, which can push potassium too high.
• People with heart failure. NICE guidance advises people with heart failure to avoid salt substitutes that contain potassium, and to have their salt and fluid intake reviewed.
• People taking losartan (the NHS says to avoid supplements and salt substitutes containing potassium), ramipril (tell your doctor about anything that can raise potassium) or spironolactone, which can raise potassium on its own.
• People taking lithium. The NHS notes that dehydration can affect lithium levels, and says to call 111 if you have an illness causing severe diarrhoea, vomiting or sweating.
• Older adults, who the NHS says should not take potassium supplements unless a doctor advises it, because kidneys clear potassium less well with age.

Magnesium adds up too. The NHS says 400 mg or less a day from supplements is unlikely to cause harm, and higher doses can cause diarrhoea. If you take a magnesium supplement as well, count both. Our guide to magnesium glycinate vs citrate covers the forms and doses.

Do electrolytes help with hangovers?

There's no good evidence that they do. A 2005 systematic review of eight randomised trials, which included glucose and fructose, found no compelling evidence that any conventional or complementary treatment prevents or treats a hangover (Pittler and colleagues). A 2021 review of 82 hangover products found no peer-reviewed human data showing that any of them was safe or effective (Verster and colleagues).

Dehydration is the usual reason people reach for electrolytes, but a 2024 review concluded that hangover and dehydration are two separate effects of drinking that happen together (Mackus and colleagues). In its survey data, drinking water during a hangover was not linked to a change in how bad people felt. We found no trial that tested an electrolyte drink against a placebo for hangovers.

Water is fine if you want a drink, and the cautions above on who should be careful still apply. If you're being sick and can't keep fluids down, call 111, as the NHS advises. The 2005 review concluded that the way to avoid a hangover is to drink less or not at all.

Do you need electrolytes on a keto diet?

Not necessarily, but people starting a keto diet can lose extra sodium and potassium in the first days, which is why electrolytes are often suggested. A 2025 scoping review explains that low carbohydrate intake cuts insulin secretion by over 50%, that insulin normally makes the kidneys hold on to sodium, and that sodium and potassium loss is greatest between days 1 and 4 and eases after about 14 days (Skartun and colleagues). The authors link the early loss to dizziness, tiredness and headache, but found no single study measuring both the symptoms and the electrolyte changes, so the link needs confirming.

One keto guide cited in the review suggests an extra 1 to 2 g of sodium a day, which is 2.5 to 5 g of salt. The NHS says adults should have no more than 6 g of salt a day, so that advice could take you well past the UK limit. If you have high blood pressure or kidney disease, or take medicines that affect sodium or potassium, ask your GP or pharmacist before adding salt or potassium.

Are electrolytes OK for kids?

For everyday drinking, no: the British Dietetic Association says water and milk are the best fluids for children. Electrolyte mixes that contain sugar also count towards the NHS limits on free sugars for children, which are 14 g a day at age 2 to 3, 19 g at 4 to 6 and 24 g at 7 to 10.

Illness is different. The NHS says to speak to a pharmacist about oral rehydration powder if a child over 5 has signs of dehydration, and to call 111 if a child under 5 shows them (such as fewer wet nappies), if you're worried about a baby under 12 months, or if a child stops feeding while ill. Keep breastfeeding or bottle feeding, and use formula at its usual strength.

The leaflet for a UK pharmacy sachet says not to use it under 24 months without medical supervision. Ask a pharmacist or GP rather than reaching for a sports electrolyte sachet.

Signs of dehydration, and of drinking too much water

The NHS lists the signs of dehydration in adults as thirst, headache, dark yellow and strong-smelling pee, peeing less often than usual, feeling dizzy or light-headed, tiredness, a dry mouth, lips and tongue, and sunken eyes. Older adults are more at risk.

In long endurance events, drinking more than you sweat can dilute the sodium in your blood, a condition called exercise-associated hyponatraemia. In a study at the 2002 Boston Marathon, 13% of 488 runners tested at the finish had low blood sodium. Gaining weight during the race and finishing in more than four hours were among the factors linked to it. At the 2003 London Marathon, 14 runners were treated for it at St Thomas' Hospital, 11 of them confused, and some only became confused after they had finished. Symptoms reported include vomiting, headache, confusion and, in severe cases, seizures.

The international consensus on exercise-associated hyponatraemia, summarised in a 2017 review by Hew-Butler and colleagues, is to drink according to thirst and to avoid gaining weight during an event. Taking sodium during a race may soften the fall in blood sodium, but it can't prevent hyponatraemia if you drink far more than you lose. Treat confusion after a long event as a medical emergency.

A quick guide: what to drink, and when

If you train regularly and are weighing up other sports supplements, our guide to creatine for women goes through what the evidence does and doesn't show.

Where Natura fits

Daily Electrolytes is in the Natura cabinet (coming soon) at our drinks shelf. Each sachet has 1,000 mg of sodium (2.5 g of salt), 250 mg of potassium, 100 mg of magnesium and 50 mg of calcium, with no sugar and no taurine, in eight flavours. It's a sweat-replacement amount, meant for training, heat or long active days, and most people won't need it every day. Magnesium contributes to electrolyte balance.