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 doctorPersistent 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.