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Electrolytes

Sodium / potassium / magnesium · Foundation

StrongFor the population and outcome described, multiple large human trials broadly agree.

Salts lost through sweat and, notably, through GLP-1 appetite suppression and low food intake.

~1,000 mg sodium
A typical high-sodium stick, about 43% of the 2,300 mg daily upper recommendation

What it is

Sodium, potassium and magnesium, the minerals that carry electrical charge in your body and control fluid balance. Less a performance supplement than a way of replacing what heavy sweating or a sharply reduced diet stops supplying.

How it works

Nerves fire and muscles contract by moving these charged minerals across cell membranes. Sustained heavy losses (or a diet that stops replacing them) can genuinely deplete you. ⚠️ But the symptoms people attribute to this (lightheadedness, headache, fatigue, fog) have many other causes including low blood pressure, low blood sugar, anemia, medication effects and plain dehydration. Persistent symptoms are worth a clinician, not a bigger scoop.

Which form to buy

Plain table salt + foodMost people, most days

Sodium is the one most often short in low-appetite states, and it is the cheapest thing in your kitchen.

Genuinely enough for many people. Start here.

Powder sticks (high-sodium)Heavy sweat, low food intake

Typically ~1,000 mg sodium per stick, a large amount that suits athletes and very low-intake days, and is overkill if you eat normally.

Convenient; read the sodium number before making it a daily habit.

Effervescent tabletsTravel & heat

Lower sodium than the powders, often with added sugar.

⚠️ NOT an oral rehydration solution, real diarrhoeal dehydration needs a product meeting the WHO ORS spec, not a sports tablet.

Coconut waterPotassium

Genuinely potassium-rich but low in sodium, which is usually the one you actually lost.

A drink, not an electrolyte strategy.

Potassium pillsRarely appropriate alone

Most US supplements sit near 99 mg, a fraction of daily need. That convention traces to FDA warning requirements for oral potassium drugs above that amount, historically because solid potassium salts caused small-bowel injury.

Food is the usual potassium source; supplemental potassium is clinician territory.

What it actually does, graded

Corrects genuine depletionStrong

Replacing real, measured losses is basic physiology rather than a supplement claim. Note this is about depletion itself, cramp prevention is graded separately below and the evidence there is weak.

Helps the "keto flu" / early low-carb slumpLimited

The mechanism is sound (carb restriction drops insulin and kidneys dump sodium) but controlled evidence for sodium as the fix is thin.

Endurance performance in long, hot sessionsLimited

Individualised fluid/sodium replacement matters in prolonged heat, but trials have not consistently shown performance gains. Irrelevant for a 45-minute gym session.

Studied for exercise crampsLimited

Popular belief, weak trial support, cramp research points more at neuromuscular fatigue than electrolytes.

General daily energyNone shown

If you are not depleted, electrolytes are just salty water.

Pros and cons

Pros
  • Fixes a real and common problem for people eating much less than usual
  • Effects show up fast when depletion is the actual cause
  • Cheap in its basic form
Cons
  • A high-sodium habit is genuinely not for everyone, blood pressure matters
  • The category is heavily marketed to people who do not need it
  • Potassium is the one you should not freelance with
  • Sugar content in some products is meaningful

What to expect

  • Where genuine depletion is the cause, replacement addresses it, but do not read a fast improvement as a diagnosis, and do not keep escalating sodium chasing one.
  • The early low-carb slump is commonly reported to settle with sodium replacement, though this was not measured as a time-to-onset effect in trials.
  • If nothing changes: depletion likely was not the cause, and persistent symptoms deserve a clinician rather than more sodium.

Interactions

CautionBlood pressure medication, heart failure, or any fluid-retaining conditionAdded sodium works against these, worth raising with whoever prescribes for you.
AvoidPOTASSIUM specifically + ACE inhibitors, ARBs, potassium-sparing diureticsThese raise potassium already; adding potassium supplements or salt substitutes is the classic route to a dangerous level. Trimethoprim, NSAIDs, heparins, calcineurin inhibitors and some beta-blockers push the same direction.
AvoidKidney diseaseImpaired kidneys clear neither potassium nor magnesium well, both can reach dangerous levels. Genuine emergency territory, not a nuisance.
TimingMAGNESIUM + tetracycline/quinolone antibiotics or oral bisphosphonatesMagnesium binds these drugs and reduces absorption, follow the separation instructions on the drug label.
MonitorLithiumSodium intake changes lithium levels in both directions; prescriber should know if your intake changes a lot.

Is it for you?

Probably worth it if
  • You are eating far less than you used to (a GLP-1, illness, or a restrictive diet), worth discussing with your clinician rather than self-diagnosing
  • You sweat heavily, train in heat, or work outdoors
  • You are early in a low-carb or fasting protocol
  • You sweat visibly through workouts and eat little salt
Probably skip it if
  • You eat a normal diet and feel fine, you are already replacing what you lose
  • You have high blood pressure, heart failure, or kidney disease and no clinician told you to add sodium
  • Your symptoms are persistent or severe, that needs assessment, not electrolytes

Who should avoid it

  • Anyone with kidney disease, or on ACE inhibitors, ARBs, or potassium-sparing diuretics, without medical supervision
  • People managing hypertension who have not discussed added sodium with their clinician

Research on this supplement

Papers about this supplement, not proof of the claims above. A title says what was studied, which is sometimes a negative result or a different question entirely.

  • Multiple Electrolytes Solution Versus Saline as Bolus Fluid for Resuscitation in Pediatric Septic Shock: A Multicenter Randomized Clinical Trial
    Crit Care Med, 2023
  • Randomized clinical trial: efficacy and tolerability of two different split dose of low-volume polyethylene glycol electrolytes for bowel preparation before colonoscopy in hospitalized children
    Pediatr Res, 2021
  • The Beverage Hydration Index: Influence of Electrolytes, Carbohydrate and Protein
    Nutrients, 2021

What the evidence says

Well-established physiology for replacing sweat losses. Branded "hydration" claims beyond that are mostly marketing.

What studies used

Varies with sweat, heat and intake. Around training or through the day.

Reported from published studies and product labelling — a record of what was used in research, not a recommendation. What is right for you is a conversation with a clinician.

Evidence base

S63,509 research papers
established literature

Large human evidence base: several phase 3 or 4 trial reports, plus multiple meta-analyses or systematic reviews.

This letter measures how much human research exists, not whether it works for you — the tier above (Strong) is the read on quality.

Research (12)

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Where next

Every supplement in the catalogThe full shelf, grouped and evidence-tiered.→The compound indexSteroids, nootropics and research chemicals.→The peptide indexInjectable peptides and what trials used.→