Most US adults eat less potassium than the Adequate Intake (3,400 mg for men, 2,600 mg for women). Even so, low blood potassium (hypokalemia, below about 3.6 mmol/L) is uncommon in healthy people with normal kidney function and is usually caused by diarrhea, vomiting, diuretics or other medical conditions rather than by diet. Severe hypokalemia can cause dangerous heart rhythm problems.
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 loop or thiazide diuretics, the most common cause
People with chronic vomiting, diarrhea or laxative misuse
People with eating disorders
People with alcohol use disorder
People recovering from severe malnutrition (refeeding syndrome)
People with diabetic ketoacidosis during insulin treatment
People with primary hyperaldosteronism or Cushing syndrome
People with rare inherited kidney disorders (Bartter or Gitelman syndrome)
People on dialysis or with very heavy sweating
When to see a doctorPersistent muscle weakness, cramps or palpitations, especially in someone on diuretics, with chronic diarrhea or with an eating disorder, warrant a blood potassium test. Do not take potassium supplements to correct a suspected low level without medical guidance: too much potassium is also dangerous, especially with kidney disease or with ACE inhibitors, ARBs or potassium-sparing diuretics.