Electrolytes

The grid above answers a narrower question than most people expect. Each grade asks "does buying an electrolyte product deliver on this specific promise?" — not "do electrolytes matter?" Electrolytes matter enormously; you would be dead without them. The grades are mostly Ds because most of what the category promises is not what the research supports.

The honest verdict, in one line: electrolytes are non-negotiable minerals, electrolyte products are situational, and most people buying them don't have the situation. Below is the reasoning behind every letter, the arithmetic that lets you check whether you're the exception, and the one number the whole industry declines to print. We sell nothing on this page and every claim is cited.

What electrolytes actually are

Electrolytes are minerals that carry an electrical charge when dissolved in body fluid — sodium, potassium, chloride, magnesium, calcium, phosphate and bicarbonate.¹ They do three jobs at once: hold water in the right compartments, generate and conduct the action potentials that fire nerves and contract muscle including your heart, and buffer blood pH.¹ Sodium is the main cation outside your cells; potassium is the main one inside, at roughly 30 times the outside concentration, and that gradient is what nerve and muscle signalling actually runs on.¹⁴ Your kidneys are the regulator, with aldosterone tuning how much sodium is reabsorbed and how much potassium is secreted.¹

That last clause is the whole reason this page exists. You don't have a "level" that rises when you drink something. You have a control system with a set point, and in a healthy person it defends that set point across a very wide range of intakes. More sodium in mostly means more sodium out.

What each electrolyte does — and which ones you're actually short on

Sodium. The fluid-balance workhorse, and the one Americans already exceed. Average intake is about 3,400 mg a day, against a Dietary Guidelines limit of less than 2,300 mg — about a teaspoon of table salt.³ The Adequate Intake for adults is lower still, 1,500 mg, and the 2019 National Academies committee's chronic-disease guidance for adults is worded as "reduce intakes if above 2,300 mg/day."² Over 70% of that sodium arrives in packaged and prepared food, not the salt shaker.³

Potassium. Sodium's intracellular counterpart, and a genuine shortfall. The AI is 3,400 mg for men and 2,600 mg for women; US adults average 3,016 mg and 2,320 mg respectively, which is why the Dietary Guidelines name potassium a nutrient of public health concern.²⁴ Supplements barely move it — among adults who take a potassium-containing supplement, it adds a mean of 87 mg a day.⁴

Magnesium. The other real gap: 48% of Americans of all ages take in less magnesium than their estimated average requirement, against an RDA of 310–420 mg.⁵ It is also the electrolyte most worth understanding on its own terms, because form and dose both matter — see the magnesium hub for the full evidence grid.

Chloride, calcium, phosphate and bicarbonate. Chloride tracks sodium and has its own AI of 2.3 g/day for adults under 51.² Calcium's RDA is 1,000 mg for most adults and 1,200 mg for women over 50 and everyone over 70, and dairy, fortified juices and plant milks, canned sardines and calcium-set tofu do most of the work.²⁶ Phosphate (RDA 700 mg) and bicarbonate are regulated tightly enough by kidney and diet that no consumer product targets them.¹²

Now the punchline. The two electrolytes with a real population shortfall are the two that electrolyte powders supply in token amounts, and the one everybody already over-eats is the one they're built to deliver.

Here is that inversion in real numbers. One stick of the market-leading hydration powder carries 560 mg of sodium and 370 mg of potassium, per the panel its maker publishes today.²¹ That single stick is 24% of an entire day's 2,300 mg sodium ceiling to buy you 11% of a man's potassium AI — more than twice as much of the mineral you're already over-eating as of the one you're short of.

Do you actually need an electrolyte supplement?

You plausibly benefit if: you're doing hard or hot exercise beyond roughly two hours — the duration at which sodium replacement is usually recommended, and sooner in real heat²⁵; you're a heavy or notably salty sweater; you're ill with vomiting or diarrhoea; you're in the early days of a low-carb diet or an extended fast; or a clinician has told you so because of a medication or condition.

You are probably solving a problem you don't have if: you sip a powder at a desk; your workouts are under an hour; or you're chasing "better hydration" while eating normally and drinking to thirst. Healthy kidneys already do this job, for free, better than any powder.¹

That's the short version. The full treatment — including what "electrolyte imbalance" actually means and what the daily-sipping habit does and doesn't do — is in are electrolytes good for you.

How to get electrolytes from food (and when a drink beats a plate)

Mineral	Best everyday sources	Reality check
Potassium	Dried apricots (755 mg per ½ cup), lentils (731 mg per cup), acorn squash, prunes, raisins, a baked potato (610 mg), kidney beans, orange juice, milk4	A banana is 422 mg — famous, but mid-table4
Magnesium	Pumpkin seeds (156 mg per ounce), chia seeds (111 mg), almonds (80 mg), boiled spinach, cashews, black beans5	Seeds and nuts beat any greens-first assumption5
Sodium	Salt, broth, olives, pickles, and essentially all packaged food3	Trivially easy. This is not the one you're missing
Calcium	Yoghurt (415 mg per 8 oz), fortified orange juice (349 mg), part-skim mozzarella, canned sardines with bones (325 mg), milk, calcium-set tofu6	Absorption from dairy and fortified foods is about 30%6

The honest exception: when losses are fast and large — a long race in heat, a bad stomach bug — the binding constraint stops being nutrition and becomes delivery. You cannot eat a plate of lentils mid-marathon. A drink wins there on speed and volume, not on nutritional superiority.

What the evidence actually supports, grade by grade

Replacing sweat and sodium during long or hot exercise

AStrong evidence

This is the claim the literature squarely supports, and it comes with the numbers nobody prints on a label.

Sweat is not just water. Across 157 marathon runners, sweat sodium averaged 42.9 ± 18.7 mmol/L, which works out to roughly 1,000 mg of sodium in every litre of average sweat.⁷ Sweat potassium, by contrast, was 6.0 mmol/L — about 235 mg per litre.⁷ That asymmetry is the entire physiological case for a sodium-forward drink during hard exercise, and the reason potassium is not the mineral you're replacing when you sweat.

The rate matters too. In 1,303 athletes measured with a standardised sweat-patch method, sodium loss ran at 51.7 ± 27.8 mmol/h in endurance sport — roughly 1,200 mg of sodium an hour — and 55.9 mmol/h in American football, against 27.2 mmol/h in baseball.⁹ The ACSM position stand's guidance follows directly: because sweat rate and sweat composition vary so much between people, fluid replacement should be customised, and you estimate your own sweat rate by weighing yourself before and after exercise.¹⁰¹¹

One disclosure the sports-nutrition field rarely volunteers: the 1,303-athlete normative dataset, and the methodology review that underpins how such data are collected, both come from the Gatorade Sports Science Institute.⁸⁹ The methods are sound and the numbers are the best available. They are also produced by a company that sells the solution. The 157-marathoner study is the independent counterweight — it was funded by a university research grant and its authors declare no competing interests, and it lands in the same range.⁷

Rehydrating faster than plain water

BModerate evidence

There is a real effect here, and it is smaller and narrower than the category implies.

In the trial that built the Beverage Hydration Index, 72 fully hydrated men drank a litre of one of 13 drinks and had their urine collected for four hours. An oral rehydration solution and both full-fat and skimmed milk produced significantly less urine than still water, with a two-hour index around 1.5 — roughly 50% more fluid retained.¹² That is the honest high-water mark for the claim.

Three caveats keep it at a B. First, a sports drink was not different from water in the same trial, alongside cola, coffee, tea, orange juice and lager.¹² Second, the subjects started euhydrated — the study measured how well a drink resists being urinated out, not how well it fixes a deficit. Third, the benchmark is an oral rehydration solution, the WHO/UNICEF formulation designed for treating dehydration from diarrhoea, which is a specific glucose-and-electrolyte recipe rather than a flavour profile.¹³ Most sugar-free hydration powders are not that.

Preventing exercise-associated muscle cramps

DInsufficient evidence

This is the most-repeated claim in the category and the one with the least behind it. Almost every consumer page — and several hospital pages — still tells the electrolyte-depletion story. The 2022 Journal of Athletic Training review does not: it concludes that a century of work points to "alterations in neuromuscular excitability and, to a much lesser extent, dehydration and electrolyte losses" as the predominant factors behind exercise-associated cramps.¹⁴ Its authors are careful — the pathophysiology is still contested, and cramps look like a confluence of individual risk factors rather than one cause — but the ordering is the opposite of the marketing.¹⁴

The observations that undercut the depletion story are specific. Runners who cramped during an ultramarathon showed no meaningful difference from non-crampers in body-weight change, blood volume, plasma volume or red-cell volume; the authors concluded there are no clinically significant alterations in serum electrolytes and no alteration in hydration status in cramping runners.¹⁵ Cramp-prone athletes drink similar volumes to everyone else. Stretching relieves cramps without changing fluid or electrolyte levels. If the cause were systemic, cramps should strike any muscle rather than only the working ones. And when participants lost 3% to 5% of body mass and about 4 g of sodium with fatigue minimised, cramp susceptibility didn't budge.¹⁴

Even the pickle-juice remedy cuts against the theory: a small volume shortened cramps by about 37% versus water without changing plasma volume, electrolytes or osmolality — the investigators attributed it to a reflex in the mouth and throat, not to the salt.¹⁴

The review's own practical line is worth quoting because it is the opposite of a product pitch: individualised prevention "will likely be more effective than generalized advice (eg, drink more fluids)."¹⁴ D is the honest grade.

Everyday hydration for people who aren't sweating hard

DInsufficient evidence

Nothing in the physiology supports a daily powder for a sedentary adult, and the arithmetic argues against it. Your kidneys regulate sodium and potassium continuously.¹ The average American is already 1,100 mg over the 2,300 mg sodium mark before adding anything.³ Adding a 560 mg stick to that day moves you further from the target, not closer.²¹

Short workouts and hangovers

DInsufficient evidence

Under about an hour, sweat losses are small enough that water does the job; the position stands frame electrolyte-and-carbohydrate drinks as useful "under certain circumstances," not as a default.¹⁰¹¹

Hangovers are simpler still: alcohol does increase fluid loss, but no controlled trial shows that an electrolyte drink changes how a hangover feels. That is an absence of evidence rather than a demonstrated failure, and D — insufficient evidence — is exactly what it means.

Keto flu and fasting

CLimited evidence

The mechanism is widely described and the symptom pattern is consistent enough that we grade this above the Ds. What is missing is any controlled trial testing whether supplementing electrolytes actually relieves the symptoms — the ACSM statements don't address low-carb or fasting states at all.¹⁰¹¹ A C here means "plausible, commonly reported, untested," and we would rather say so than round it up. The dietary-context detail lives in keto electrolytes and electrolytes for fasting.

The three things nobody actually knows

1. Your sweat sodium is individual, and it isn't measurable at home. In those 157 marathoners, sweat sodium ranged from 7.0 to 95.5 mmol/L — a fourteen-fold spread, or roughly 160 mg to 2,200 mg of sodium per litre of sweat.⁷ One in five was above 60 mmol/L.⁷ Critically, sweat electrolyte concentration did not correlate with sweat rate, age, body characteristics, training or experience.⁷ There is no proxy. Nobody — including us — can tell you your number from a web page, and neither can a product label.

2. Sweat testing itself is contested. Published sweat-sodium figures disagree partly because the measurement does. Collection system (whole-body washdown versus a local patch), timing and duration, skin cleaning, sample handling and analytical technique all move the result, and unstandardised field practice can produce inconsistent or inaccurate numbers.⁸ Treat any single published figure, including the ones on this page, as a population average with wide error bars.

3. Whether more sodium harms a healthy, active person is genuinely unsettled. Two bodies of high-quality evidence point different ways, and the difference is study design.

The randomised side is clear. In DASH-Sodium, 412 people ate high, intermediate and low sodium for 30 days each under controlled feeding; dropping from intermediate to low sodium lowered systolic pressure by a further 4.6 mmHg on the control diet, and the low-sodium DASH diet ran 11.5 mmHg below the high-sodium control diet in people with hypertension.¹⁸ The Cochrane review of 34 trials in 3,230 people found that cutting salt by about 4.4 g/day lowered systolic pressure by 4.18 mmHg (95% CI −5.18 to −3.18), more in hypertensive people than normotensive ones.¹⁹

The observational side disagrees at the low end. PURE followed 101,945 people in 17 countries and found a J-shaped curve: estimated sodium excretion at or above 7 g/day carried higher risk of death and cardiovascular events (OR 1.15), and so did excretion below 3 g/day (OR 1.27).²⁰ Its authors concluded that 3 to 6 g/day looked better than either extreme — well above the 2,300 mg guidance.²⁰

We are not going to resolve that for you, because it isn't resolved. What we will name is the design gap: DASH-Sodium and the Cochrane trials are randomised, measure blood pressure directly, and run for weeks; PURE is an observational cohort that estimated habitual intake from a single morning spot-urine sample and tracked hard endpoints for 3.7 years — a design in which reverse causation (people who are already ill eat less) and estimation error are live concerns.²⁰

The defensible position: for anyone with high blood pressure, kidney disease or heart failure, the guidance is conservative and consistent, and it comes from your clinician. For a healthy endurance athlete replacing measured sweat losses, a population-level ceiling designed around packaged food may simply be the wrong frame. Both of those can be true.

Can you have too many electrolytes?

Yes, in both directions, and both are medical situations rather than something to self-manage.

Too much sodium raises blood pressure across the population, and diets higher in sodium are associated with increased risk of developing high blood pressure.³ That effect is strongest in people who already have hypertension.¹⁹

Too much fluid relative to sodium is the sharper acute risk. Hyponatremia — blood sodium below 135 mmol/L — is the most common electrolyte disorder in hospitalised patients, and it arises in endurance events when drinking beyond thirst combines with sweat solute loss and hormonal water retention; more than roughly 750 mL an hour can outpace the kidneys' ability to excrete water.¹¹⁶ Symptoms escalate from headache and fatigue through confusion to cerebral swelling.¹⁶ An international consensus conference has been convened specifically on exercise-associated hyponatremia, which tells you how real it is.¹⁷ If someone gets confused or unwell during or after a long event, that is an emergency call, not a hydration adjustment.

Potassium deserves its own caution. Manufacturers cap potassium supplements at 99 mg per serving because the FDA has ruled that oral drug products delivering more than that are unsafe, having been associated with small-bowel lesions.⁴ Healthy kidneys handle dietary potassium well enough that no upper limit was set — but in chronic kidney disease, or on ACE inhibitors, ARBs or potassium-sparing diuretics, even intakes below the AI can push blood potassium too high.⁴ The same is true in type 1 diabetes, heart failure, adrenal insufficiency and liver disease.⁴ If you're in any of those groups, salt substitutes and high-potassium powders are a conversation with your clinician before they're a purchase.

One medication is worth naming separately. Lithium reduces sodium reabsorption in the kidney, and people taking it are advised to keep salt and fluid intake steady, with prescribers watching for dehydration during heavy sweating or diarrhoea.²⁴ That makes a new electrolyte habit a question for the prescriber, not a self-managed variable.

None of this is medical advice, and nothing on this page describes how to manage any of these conditions.

How much of each electrolyte do you need?

The dosage card above is the summary; here is the point it exists to make. There is no RDA for an "electrolyte drink." Targets are set per mineral, from all sources combined — sodium AI 1,500 mg with chronic-disease guidance to reduce intake above 2,300 mg; potassium 2,600–3,400 mg; magnesium 310–420 mg, with a separate 350 mg/day ceiling for supplemental magnesium that doesn't apply to food; calcium 1,000–1,200 mg; chloride 2.3 g/day to age 50.²⁵ Against a full day of food, a stick pack is a rounding error for all of them except sodium. Our how much magnesium per day guide handles that mineral properly.

For the exercise case, work from losses rather than labels: about 1,000 mg of sodium per litre of average sweat, and roughly 1,200 mg an hour for endurance athletes as a population mean, with an enormous individual spread either side.⁷⁹

Choosing a product, if you decide you need one

Four things actually differentiate these products. None of them is the word "electrolytes" on the front.

1. Sodium per serving, matched against your losses. This is the only spec that changes what the product does, and the range is astonishing. Three powders on the market right now, all sold as electrolytes: one stick with 560 mg of sodium, another with 60 mg, and a third with 5 mg.²¹²²²³ That is a hundred-fold spread inside one category. The 560 mg stick replaces a little over half a litre of average sweat; the 5 mg one replaces essentially none of it and is doing something else entirely.

2. Sugar — and whether you want the oral-rehydration logic or not. The evidence for beating plain water comes from an oral rehydration solution, which contains glucose by design.¹²¹³ A sugar-free powder is a different product with a different rationale. Neither is wrong, but they aren't interchangeable, and the trial data belongs to the sugared one.

3. Potassium and magnesium content — and the honest advice not to buy one for those. Those same three products carry 370, 205 and 75 mg of potassium.²¹²²²³ Against a 2,600–3,400 mg AI, none of that is a fix. If magnesium is what you're after, buy magnesium — the form matters, and types of magnesium grades each one.

4. Third-party certification, if you're drug-tested. NSF Certified for Sport or Informed Sport is the only signal that the tub contains what the panel says.

For a worked head-to-head on the two products most people actually choose between, see LMNT vs Liquid I.V. — that page names products and carries affiliate links; this one deliberately doesn't.

Frequently asked questions

The bottom line

Electrolytes are essential. Electrolyte products are a delivery system for sodium, marketed as though everyone needs one, sold into a population that already eats 3,400 mg of sodium a day and falls short on potassium and magnesium instead.³⁴⁵ If you're sweating hard for over an hour, or ill, or a genuinely salty sweater, they solve a real problem and the A grade above is honest. If you're at a desk, water and food already do it.

The uncertainty is real too, and we'd rather leave it visible than tidy it away. Nobody can tell you your sweat sodium from a web page, the measurement itself is contested, and whether extra sodium harms a healthy active person is a live argument between randomised trials and cohort data. What we can give you is the arithmetic, the grades behind it, and where every number came from.