Do electrolytes prevent cramps?

The review analysing the hypotheses on exercise-associated cramps concludes that the support for dehydration and electrolyte loss is weak, based on clinical observations, case series of 18 cases and a study with 10 subjects, and that four prospective cohort studies do not back it. What keeps gathering data is the altered neuromuscular control hypothesis, linked to fatigue.

Does potassium lower blood pressure?

In people with hypertension, yes: the meta-analysis finds 3.49 mmHg lower systolic and 1.96 lower diastolic. In people without hypertension that effect is not seen. Also, higher potassium intake is associated with 24% lower stroke risk in cohort studies.

How much potassium should you take?

The European labelling reference is 2000 mg a day counting all food. It is covered by fruit, vegetables, legumes and potatoes long before capsules, which also contain small doses for safety reasons.

Can I take potassium if I take blood pressure pills?

Ask first. Several common blood pressure treatments retain potassium, and adding a supplement can push it too high, which is a serious heart problem. The same applies with kidney disease.

Home / Potassium and electrolytes / Guide

Potassium and electrolytes · Moderate evidence

What potassium and electrolytes are for

The short answer. Potassium is a mineral with good evidence in one specific place: increasing intake lowers blood pressure in people with hypertension, and it is associated with fewer strokes. That is its real story, and it is a health story, not a gym story. The story told in sport is different: that electrolytes prevent cramps. The review examining that hypothesis concludes that the evidence for dehydration and electrolyte loss is weak, and that what keeps gathering data is altered neuromuscular control.

There are studies in favour, but few, with small samples or measuring markers instead of outcomes. No figure on this page is attributed to a specific product: the effect belongs to the ingredient and every number carries its source next to it.

01 What it does and how much

Each row is a measured effect, with the figure the study gives and the source number. Where the evidence gives no figure, the column says so instead of making up a percentage.

Effects of potassium with their source
Effect	How much	Detail
Systolic blood pressure in hypertensive people	-3.49 mmHg	Twenty-two trials with 1606 participants. Diastolic falls by 1.96 mmHg. The effect is seen in people with hypertension and not in those without it. [2]
Stroke risk	RR 0.76	In eleven cohort studies with 127,038 participants: 24% fewer strokes with higher potassium intake, with moderate quality evidence. For cardiovascular or coronary disease overall it was not significant. [2]
Kidney function and lipids	no adverse effect	Increasing potassium did not worsen kidney function, lipids or catecholamines in adults. The important caveat is that this applies to people who handle potassium normally, not to those with kidney disease. [2]
Exercise-associated cramps	weak hypothesis	The evidence for electrolyte loss and dehydration comes from clinical observations, case series of 18 cases and a case-control study with 10 subjects, and four prospective cohort studies do not support it. [3]
Nutrient reference value	2000 mg	The European labelling figure. A banana has around 350 mg, so dietary potassium adds up quickly with fruit, vegetables and legumes. [1]

02 How to take it

Dose. The labelling reference is 2000 mg a day, counting all food.
When. With meals. Electrolyte drinks are used during or after long, sweaty efforts.
How long before you notice it. The effect on blood pressure is measured over weeks of sustained intake, not a single dose.

Details that change the result

Potassium supplements in Europe contain small doses for safety: potassium in quantity is a heart matter, not just any mineral.
With kidney disease, potassium-sparing diuretics or ACE inhibitors, do not supplement this on your own.
For long, sweaty efforts, the electrolyte lost and replaced most is sodium, not potassium.
The cheap, best-supported way to raise potassium is food: fruit, vegetables, legumes and potatoes.

03 When it makes sense and when it does not

Worth it if

With high blood pressure and a diet low in fruit and vegetables, understanding that the main route is food.
Long efforts in the heat with heavy sweating, as part of a drink with sodium, not a potassium capsule.

Not worth it if

With kidney disease or medication that retains potassium, unless medically advised.
To prevent cramps, the promise the specific review does not support.
Without high blood pressure, where the meta-analysis finds no effect on blood pressure.

04 Sources

Every figure above comes from here. They are position stands from scientific societies, meta-analyses and peer-reviewed reviews: if a claim cannot hang from one of these lines, it is not on the page. References are cited in their original form.

Reglamento (UE) 1169/2011 sobre la informacion alimentaria facilitada al consumidor, Anexo XIII: valores de referencia de nutrientes. Potasio, 2000 mg. Es un valor de ETIQUETADO, no una dosis con efecto demostrado. https://eur-lex.europa.eu/legal-content/ES/TXT/?uri=CELEX%3A32011R1169
Aburto NJ et al. Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses. BMJ. 2013;346:f1378. Veintidos ensayos con 1606 participantes: descenso de 3,49 mmHg de tension sistolica (IC 95 % 1,82-5,15) y 1,96 mmHg de diastolica, solo en personas con hipertension; once cohortes con 127.038 participantes: riesgo de ictus 0,76 (IC 95 % 0,66-0,89). doi:10.1136/bmj.f1378
Schwellnus MP. Cause of exercise associated muscle cramps (EAMC): altered neuromuscular control, dehydration or electrolyte depletion? Br J Sports Med. 2009;43(6):401-408. La evidencia a favor de las hipotesis de deshidratacion y perdida de electrolitos procede de observaciones clinicas, series de 18 casos y un estudio de casos y controles con 10 sujetos, y cuatro estudios de cohortes prospectivos no la respaldan. doi:10.1136/bjsm.2008.050401

This is not medical advice. It is what some studies say about an ingredient, not a protocol for you. With an illness, medication or pregnancy involved, the decision belongs to a healthcare professional who knows you.

Questions about potassium

Answered with the data on this page

Do electrolytes prevent cramps?: The review analysing the hypotheses on exercise-associated cramps concludes that the support for dehydration and electrolyte loss is weak, based on clinical observations, case series of 18 cases and a study with 10 subjects, and that four prospective cohort studies do not back it. What keeps gathering data is the altered neuromuscular control hypothesis, linked to fatigue.
Does potassium lower blood pressure?: In people with hypertension, yes: the meta-analysis finds 3.49 mmHg lower systolic and 1.96 lower diastolic. In people without hypertension that effect is not seen. Also, higher potassium intake is associated with 24% lower stroke risk in cohort studies.
How much potassium should you take?: The European labelling reference is 2000 mg a day counting all food. It is covered by fruit, vegetables, legumes and potatoes long before capsules, which also contain small doses for safety reasons.
Can I take potassium if I take blood pressure pills?: Ask first. Several common blood pressure treatments retain potassium, and adding a supplement can push it too high, which is a serious heart problem. The same applies with kidney disease.

And now, which to buy

Prices, kept apart from the evidence

This page explains what potassium does and deliberately names no brand. The comparison is the other half: 34 products from 5 stores from €0.062 per capsule, sorted by price and by how verifiable their certification is.

See the potassium and electrolytes comparison

Other guides

What each supplement does, with its sources