Electrolytes: what is in the mix?

Somewhere between the salty crust on your cap and the sachet rattling in your running belt sits a perfectly reasonable question: do you actually need to put the salt back? Sometimes yes. Often no. And the front of the pack will not tell you which.

Here is the short version. For most workouts under about an hour, water and normal food cover it. Added electrolytes start to earn their place in long, hot or heavy-sweat sessions, and even then the amount depends on you, not on the sachet. The better-documented danger in endurance events is not too little salt but too much plain water, which can dilute blood sodium to a level that makes people ill. Let's go through what is in the mix, who it is for, and how to read a label without needing a chemistry set.

What "electrolytes" means on a label

Electrolytes are minerals that carry an electrical charge when dissolved in body fluid, which is what lets nerves fire and muscles contract. On sports-drink labels the usual cast is sodium, chloride, potassium and magnesium.

Sweat is mostly water with a little salt, and the mix is not even. A review of sweat testing in athletes reports that:

• freshly made (primary) sweat is similar in saltiness to blood plasma, but most of the sodium and chloride is reabsorbed on the way out, so final sweat is much less salty;
• whole-body sweat sodium typically falls in a range of about 10 to 70 mmol per litre, and sweat rate typically ranges from about 0.5 to 2.0 litres an hour;
• potassium in final sweat is low, roughly 2 to 8 mmol per litre, similar to blood plasma.

(Baker, 2017, Sports Medicine.) The sweat figures in that review come largely from athletes tested by the Gatorade Sports Science Institute, a sports-drink maker's research unit, which is worth knowing though the ranges are consistent with the wider literature the paper cites.

Sodium has a molar mass of about 23 g per mole, so 1 mmol of sodium is roughly 23 mg. That converts the sweat range above to around 230 to 1,600 mg of sodium per litre of sweat. Multiply by a sweat rate between half a litre and two litres an hour and you can see why two runners on the same route can lose very different amounts. It is also why the same sachet can be too much for one person and too little for another.

Magnesium is the odd one out. It's on many electrolyte labels, but there's no sweat-loss figure for it to cite here, so we don't put a number on it.

Salt on the cap: who needs to top up, and who probably doesn't

The American College of Sports Medicine's 2007 position stand on fluid replacement says the goal of drinking during exercise is to avoid excessive dehydration (more than 2 per cent of body weight lost as water) and excessive changes in electrolyte balance. Because sweat rates and sweat saltiness vary so much between people, it recommends customised plans, suggests working out your own sweat rate by weighing yourself before and after exercise, and says drinks containing electrolytes and carbohydrate can offer benefits over water alone "under certain circumstances" (Sawka et al., 2007, Medicine & Science in Sports & Exercise).

Putting that together, in plain terms:

• Probably not needed: an easy 30 to 60 minute run, a gym session, or a normal working day. Food already supplies sodium and potassium. The WHO recommends adults eat less than 2,000 mg of sodium a day (less than 5 g of salt) and reports global average intake of 4,278 mg of sodium, equivalent to 11 g of salt, in 2021 (WHO, fact sheet dated 11 May 2026). Adding salt by reflex to a short workout rarely fills a gap.
• Worth thinking about: long sessions, hot or humid conditions, heavy sweating, white salt marks on kit, or several hard sessions in a day. These are the situations where sodium losses become large enough to matter and where an electrolyte drink may help with taste, drinking and sodium replacement.
• Check with a professional first: if you have been told to limit sodium or potassium (for example for high blood pressure, heart or kidney problems), or you take medicines that affect them. The NHS notes that older people may be at greater risk from potassium supplements because their kidneys may remove it less well, and advises them not to take potassium supplements unless a doctor says so (NHS, vitamins and minerals; this is UK guidance). Our guide to supplement and drug interactions covers how to raise the question.

If you want to know where you sit, the sweat-testing review says the simplest and most accurate way to estimate sweat rate is the change in body mass during exercise, with caveats about things like trapped sweat in clothes. Lab-style sweat sodium testing is useful only when it is done carefully, and results from the field vary with technique (Baker, 2017). A before-and-after weigh-in costs nothing; a salt-patch test is a bigger ask.

The risk nobody puts on the sachet: drinking too much

Exercise-associated hyponatraemia (EAH) is a low blood sodium concentration, usually defined as below 135 mmol per litre, that develops during or soon after exercise. A 2017 review of the field describes how the 2015 international consensus conference concluded that the main cause is drinking more hypotonic fluid (plain water or sports drinks) than the body loses, combined with the body holding on to fluid through the hormone vasopressin. A smaller share of athletes lose sodium faster than they replace it, and some cases involve both (Hew-Butler et al., 2017, Frontiers in Medicine).

Two points from that review stand out for anyone tempted to treat salt as the cure-all:

• Hyponatraemia and cramping were unrelated to total sodium intake in a 161 km ultramarathon, and a case study found oral sodium did not necessarily prevent symptomatic EAH in someone who had overdrunk.
• The same review notes a weakly positive link between sodium supplementation and post-race blood sodium in that 161 km race (156 participants), which the study's authors read as a minimal contribution to preventing hyponatraemia. It also describes a small study in which endurance-trained men on a low-sodium diet had lower plasma sodium before and during exercise. So the evidence is thin in both directions: salt is not a proven fix, and it is not proven irrelevant.
• The review says all deaths attributed to EAH would probably have been prevented by better understanding of hydration needs and by recognising the signs quickly.

A 2025 systematic review of 56 field studies, covering 220 EAH cases in outdoor endurance activities lasting 5 to 29.5 hours, found that running and hiking produced far more cases than cycling, swimming or triathlon, and that women accounted for a greater percentage of cases (not a greater number) than men. Mild symptoms were typically nausea, weakness, dizziness, headache and swelling in the hands or feet. Signs of the more severe form included altered mental state, vomiting, seizure, collapse and loss of consciousness (Armstrong et al., 2025, Open Access Journal of Sports Medicine).

If someone is confused, vomiting repeatedly or collapses after a long event, that is a medical emergency; more water is not the answer. The 2017 Hew-Butler review says intravenous hypertonic saline is the most effective treatment for the severe form, and that hypotonic fluids are contraindicated once EAH is confirmed. That is care for paramedics, not something to improvise at the finish line.

The practical lesson from all this: avoid drinking far beyond thirst, and know the symptoms. Neither requires a purchase.

Do electrolytes stop cramps?

It's the claim most sachets imply, and the one with the thinnest support. A 2009 review in the British Journal of Sports Medicine found that evidence for the electrolyte-depletion and dehydration explanations for exercise-associated muscle cramps came mainly from anecdotal observations, case series totalling 18 cases and one small case-control study (10 people), while four prospective cohort studies did not support them. The author concluded that altered neuromuscular control, essentially muscles fatiguing and misfiring, has the stronger support as the main mechanism (Schwellnus, 2009). That review is some years old and doesn't rule out a benefit for some people, but it's a reason not to expect a mineral drink to rescue a cramp.

A worked label example: Orangefit Hydrate

Reading a label is easier with a real one. Orangefit's Dutch product page for Hydrate, a powder electrolyte mix, was read on 8 October 2026; this is supplier information and it can change. The page lists these amounts per drink (one 7 g scoop mixed with 500 ml water, for the Lemon Orange flavour; the nutrition values we quote were headed "Lemon Orange" and we don't assume other flavours match):

• Per 7 g scoop: Energy; Amount on the page: 3 kcal
• Per 7 g scoop: Carbohydrate (of which sugars); Amount on the page: 0.3 g (0 g)
• Per 7 g scoop: Salt; Amount on the page: 2 g
• Per 7 g scoop: Sodium; Amount on the page: 800 mg
• Per 7 g scoop: Potassium; Amount on the page: 320 mg
• Per 7 g scoop: Magnesium; Amount on the page: 75 mg
• Per 7 g scoop: Chloride; Amount on the page: 1,090 mg

The page lists the ingredients as Himalayan sea salt, potassium citrate, magnesium citrate, acidity regulators, an anti-caking agent, natural flavouring and a stevia-based sweetener, and gives 43 drinks per 300 g pack (which checks out: 7 g times 43 is 301 g). It describes the product as "electrolytes for every day" supporting daily hydration.

The page prints 1,090 mg of chloride next to 800 mg of sodium. We quote the figures as printed; the pack's own label is the one to check.

Now let's do what the label does not do for you:

1. Convert sodium to something comparable. 800 mg of sodium is about 35 mmol (800 divided by 23). Dissolved in 500 ml, that is roughly 70 mmol per litre, ignoring the small volume of the powder. Against the sweat range above of about 10 to 70 mmol per litre, one scoop in half a litre sits at the top of what sweat contains. That is not a verdict. It simply tells you this is a salty drink compared with typical sweat, and more dilute in a bigger bottle.
2. Check the salt equivalent. Multiplying sodium by 2.5 gives 2.0 g of salt, which is what the page states. Against the WHO's less-than-5 g a day, one scoop is about two-fifths of that. If it is your only extra salt on a day you also eat normally, that is easy to tolerate; if you drink several scoops, it adds up.
3. Compare the minerals. 75 mg of magnesium sits well below the 400 mg a day from supplements that the NHS says is unlikely to cause harm, though the NHS notes taking more than 400 mg of magnesium for a short time can cause diarrhoea. Potassium at 320 mg is likewise small next to the NHS's 3,700 mg supplement figure.
4. Notice what is missing. With 0.3 g of carbohydrate, this is not an energy drink. A hard session that needs fuel would need carbohydrate from somewhere else.
5. Read the claims against the rulebook. The page says magnesium citrate contributes to normal muscle function and helps reduce tiredness, and that potassium contributes to normal muscle function. Those mirror authorised EU wording for magnesium and potassium (below). They describe the nutrients' normal roles, not what a drink does mid-marathon.

The magnesium here is citrate. For how magnesium forms differ, see our magnesium types guide.

What the EU allows an electrolyte pack to claim

The claim wording below comes from a copy of Commission Regulation (EU) No 432/2012 hosted on legislation.gov.uk (read 8 October 2026). Because it's a UK-hosted copy, check the Official Journal for the current text. The rules apply in the Netherlands as in other member states.

• Carbohydrate-electrolyte drinks: two claims exist, that these solutions "contribute to the maintenance of endurance performance during prolonged endurance exercise" and "enhance the absorption of water during physical exercise". They come with a recipe: 80 to 350 kcal per litre from carbohydrate, at least 75 per cent of that energy from fast carbohydrates such as glucose or sucrose, 20 to 50 mmol per litre of sodium, and an osmolality of 200 to 330 mOsm per kg. A drink with almost no carbohydrate, such as the example above, is outside that recipe by design.
• Magnesium: authorised wording includes contributing to electrolyte balance, normal muscle function, normal nervous-system function and a reduction of tiredness and fatigue, for foods that are at least a source of magnesium.
• Potassium: contributes to normal muscle function, normal nervous-system function and normal blood pressure, again for foods that are at least a source.
• Chloride: one claim, about normal digestion through stomach acid production, which the text says cannot be used where the source is sodium chloride.

None of these is a promise about cramps, or performance on a long run, and a pack that makes such a promise is worth a second look.

Powder, tablet, gel or bottle: what actually differs?

We haven't found head-to-head studies of tablets against powders against gels for runners, so what follows is practical reasoning rather than trial evidence.

• Format: Powder or sticks; What is usually different: Most flexible; you control dilution and bottle size; Things to check: Is the scoop measured in your units? Does the flavour survive warm water?
• Format: Effervescent tablets; What is usually different: Convenient to carry; dose per tablet fixed; Things to check: Sodium and other minerals per tablet; extra sweeteners; whether you need more than one
• Format: Gels and chews; What is usually different: Mostly carbohydrate; some contain sodium or caffeine; Things to check: Carbohydrate per portion, sodium per portion, need to drink water alongside
• Format: Ready-to-drink; What is usually different: No mixing, heavy to carry; Things to check: Concentration of sodium per 100 ml and price per serving
• Format: Carbohydrate-electrolyte drink mixes; What is usually different: Combine fuel and sodium in one bottle; Things to check: Carbohydrate per litre, sodium per litre

The more useful question than "which format?" is "what job are we hiring this for?": replacing sodium, supplying carbohydrate, or just making water easier to drink. The same label can do one of those well and the others not at all.

Elsewhere on the Dutch shelf: Upfront and Orangefit

These are supplier details read on 8 October 2026 and may change; we haven't tested the products.

Orangefit's electrolyte page is the Hydrate powder analysed above. Upfront's Dutch catalogue lists, among its running and sports products, electrolyte sticks (sold in 10-stick and 30-stick formats), a ready-to-drink electrolyte product, an "ISO Drink" described as a sports drink for intense exercise with 66 g of carbohydrate per portion, and an "Intra Endurance" drink whose page says it provides 66 g of carbohydrate, 0.49 g of salt and 100 mg of caffeine in the orange flavour. It also lists a "Gel 2.0" in several flavours. Check the pack for sodium and carbohydrate before comparing with Hydrate.

Four questions before you reach for a sachet

1. How long and how hot? Under an hour and cool, water and food are usually enough. Long and hot is where electrolytes become a real question.
2. How much do you sweat? Weigh before and after a typical session to estimate it; a change of more than 2 per cent of body weight is the line ACSM uses for excessive dehydration.
3. What does the label give you per serving, in numbers I can compare? Convert sodium to mg per litre of finished drink.
4. Are you drinking to thirst, or to a plan? Overdrinking is the documented hazard, and no electrolyte product fixes it.

That is the whole decision. Electrolyte mixes can be a pleasant, convenient way to replace some of what long, sweaty sessions cost you. Most people don't need them most of the time, and the evidence doesn't back them as a cramp cure.

For more on reading labels in general, see our guide to reading supplement labels. If you take medicines or have a heart, kidney or blood-pressure condition, talk to your doctor or pharmacist before using electrolyte products regularly.

Written by Smart Supplements with AI assistance from the sources linked in the text. It has not been reviewed by a clinician.

Last updated: 12 October 2026

This article is for informational purposes only and is not intended as medical advice. Always consult a healthcare professional before starting any new supplement, especially if you take prescription medication.