Low potassium levels (hypokalemia) usually result from losing too much potassium from the body, less often from not getting enough in the diet.

Common medical causes

• Vomiting, diarrhea, or overuse of laxatives can cause large losses of potassium through the digestive tract.

• Kidney problems and certain hormonal disorders (like excess aldosterone or Cushing syndrome) make the kidneys waste potassium in the urine.

• Inherited conditions such as Bartter, Gitelman, or Liddle syndromes can also lead to chronic potassium loss.

Medication and substance causes

• Diuretics (“water pills”) used for high blood pressure or heart failure are the most common medication cause of low potassium, because they increase potassium loss in urine.

• Other medicines, including some antibiotics, steroids, insulin, and frequent laxative use, may also lower potassium.

• Heavy alcohol use and high salt intake can contribute to potassium loss or poor balance.

Diet and absorption issues

• Not eating enough potassium-rich foods alone rarely causes hypokalemia, but poor intake can worsen other causes, especially in malnutrition or eating disorders.

• Conditions that impair nutrient absorption (such as chronic diarrhea or inflammatory bowel disease) reduce how much potassium the gut can take up.

• Low magnesium levels can make hypokalemia harder to correct because magnesium is needed for normal potassium handling.

Other triggers and risk factors

• Excessive sweating (from heat, heavy exercise, or fever) can contribute to potassium loss, especially if fluids are not replaced properly.

• Dehydration from any cause, including prolonged vomiting or diarrhea, increases the risk.

• Certain endocrine and metabolic states (like diabetic ketoacidosis or primary aldosteronism) shift potassium out of the blood or increase its excretion.

If you suspect low potassium (for example, due to weakness, cramps, or palpitations), it is important to get a blood test and talk with a clinician promptly, especially if you are on diuretics, have ongoing vomiting/diarrhea, or a kidney or hormone disorder.