Potassium deficiency
Symptoms, at-risk groups, and clinical context for potassium deficiency. Sourced from NIH Office of Dietary Supplements and StatPearls.
Most Americans consume less potassium than recommended (the AI is 3,400 mg for men, 2,600 mg for women). However, true hypokalemia (serum <3.5 mmol/L) is usually caused by medical conditions or medications rather than dietary insufficiency, since healthy kidneys conserve potassium efficiently. Severe hypokalemia can be life-threatening due to cardiac arrhythmias.
Common symptoms
- Muscle weakness, especially in legs
- Muscle cramps or spasms
- Fatigue and low energy
- Constipation, bloating, or abdominal discomfort
- Heart palpitations or irregular heartbeat
- Tingling or numbness
- Excessive thirst, frequent urination
- Severe cases: muscle paralysis, life-threatening arrhythmias, respiratory failure
At-risk groups
- People taking diuretics (loop diuretics like furosemide, thiazides) — most common cause
- People with chronic vomiting, diarrhea, or laxative abuse
- People with eating disorders (bulimia, anorexia)
- People with alcohol use disorder
- People with refeeding syndrome (recovery from severe malnutrition)
- People with diabetic ketoacidosis or insulin recovery
- People with primary hyperaldosteronism or Cushing syndrome
- People with rare genetic disorders (Bartter, Gitelman syndromes)
- People with very low overall food intake
When to see a doctor: Persistent muscle weakness, cramps, or palpitations — especially in someone on diuretics, with chronic diarrhea, or with an eating disorder — warrants a serum potassium test. CRITICAL: do NOT take potassium supplements without medical guidance. Excess potassium (hyperkalemia) is also dangerous and can cause fatal arrhythmias, especially in people with kidney disease or those on ACE inhibitors, ARBs, or potassium-sparing diuretics.
← All deficiencies
Related deficiencies
Nutrients with overlapping symptoms — useful when investigating an unclear clinical picture.