Potassium is a mineral and electrolyte that supports some of your body's most basic functions. Without it, your heart wouldn't sustain a steady rhythm, your nerves and muscles wouldn't contract properly and your body couldn't maintain its balance of fluids.
Your body usually does a pretty good job of keeping potassium levels normal. That's generally between 3.6 and 5.2 millimoles per liter of blood (mmol/L), according to the Mayo Clinic. Certain groups of people, though, can benefit from taking either over-the-counter or prescription potassium supplements.
How Much Potassium Do You Need?
The Dietary Guidelines for Americans recommend a daily minimum of 3,400 milligrams (mg) of potassium for men and 2,600 for women.
Most healthy people should be able to get the daily recommended intake of potassium from their diet. The Academy of Nutrition and Dietetics lists bananas, potatoes, cantaloupe, spinach, raisins and milk among the many foods that are high in potassium.
But there are benefits of potassium pills and other forms of the supplement for certain people at certain times.
Who Are Potassium Supplements For?
Doctors may prescribe or recommend potassium supplements for people who have hypokalemia, which is when you don't have enough potassium. Hypokalemia is caused by losing too much potassium, typically through urine, stool or sweat, explains the National Organization for Rare Disorders. This, in turn, can be caused by a number of things including taking diuretic drugs, overusing laxatives, having chronic diarrhea or vomiting, not getting enough magnesium, eating disorders such as bulimia, chronic kidney disease and certain genetic disorders.
People who are seriously ill and hospitalized, especially children, seem to be prone to hypokalemia, according to a September/October 2014 report published in the Journal of Intensive Care Medicine. Hyperaldosteronism, which means having too much of the hormone aldosterone that usually helps balance potassium and sodium, can also deplete potassium levels, according to Kaiser Permanente.
Supplements Used to Treat Hypokalemia
The best potassium supplement depends on what it's being used for. In general, potassium chloride works well and is the most common supplement for treating hypokalemia. "Most of the time, potassium chloride is the source of choice if you're potassium deficient," says Maria DeVita, MD, chief of nephrology at Lenox Hill Hospital in New York City.
Potassium chloride has a strong salty taste, according to the National Center for Biotechnology Information. In fact, it's commonly found in salt substitutes. Potassium gluconate is also sometimes used to treat hypokalemia.
Other Potassium Supplements
Other types of potassium supplementation can be helpful, usually for health issues other than hypokalemia. According to the Office of Dietary Supplements (ODS), potassium citrate, phosphate, aspartate and bicarbonate have all been used as dietary supplements.
Doctors sometimes prescribe potassium citrate to people who get kidney stones, says Gerald Hladik, MD, chief of the division of nephrology and hypertension at the University of North Carolina School of Medicine. This supplement can also help prevent kidney stones, according to the Mayo Clinic.
Potassium phosphate may be prescribed for people who are deficient in phosphate, adds Dr. DeVita. Phosphate is a mineral that plays a role in strong bones and teeth, among other things, per the National Library of Medicine. There's limited evidence that potassium bicarbonate or potassium citrate may help with bone health too, according to the ODS.
According to the American College of Cardiology (ACC), potassium supplements come in powders, granules, liquids, tablets and capsules. Powders, granules and liquids can be mixed into water or juice.
Possible Side Effects and Interactions of Potassium Supplements
Some of the less serious side effects of potassium supplements can include mild nausea or diarrhea, an upset stomach and a tingling sensation in your hands and feet, according to the ACC. More serious problems include diarrhea or vomiting that continues, stools that are black or bloody, weak muscles and an abnormal heartbeat.
Over-the-counter potassium supplements usually contain no more than 99 mg of the mineral — or only 3 percent of the daily recommended intake — which makes it difficult to take too much, according to the ODS. But it can happen: Symptoms of an overdose may include a changed heartbeat, seizures, confusion and shallow breathing, the ACC reports.
Read more: Symptoms of a Potassium Overdose
Prescription doses may be higher, but you can only take those under the guidance of a doctor who will monitor your potassium levels closely. Your doctor will be able to tell which is the best form of potassium supplement for your particular needs.
Potassium supplements can interact with some medications. According to the ACC, these include:
- Certain heart medications such as eplerenone (Inspra), digoxin (Lanoxin) and ACE inhibitors such as fosinopril (Monopril) and benazepril (Lotensin)
- Some diuretic medications
- Bronchodilators used to treat asthma such as tiotropium (Spiriva)
- Quinidine (Quinidex), used to treat irregular heartbeats as well as malaria
Warnings About Potassium Supplements
Potassium supplements could be dangerous if you have too much potassium or hyperkalemia, which can be caused by kidney disease, according to the National Kidney Foundation. "High potassium levels can be life-threatening and cause cardiac arrest," warns Dr. Hladik. Certain potassium-sparing diuretics, like spironolactone (Aldactone), can also cause potassium to collect. Talk to your doctor to see if any medications you're taking can lead to hyperkalemia.
You also shouldn't take potassium supplements if you have Addison's disease, severe burns, heart disease, high blood pressure or chronic diarrhea from Crohn's disease, warns the ACC.
- Mayo Clinic: “High Potassium (Hyperkalemia)”
- 2015-2020 Dietary Guidelines for Americans: "Shifts Needed to Align With Healthy Eating Patterns"
- Academy of Nutrition and Dietetics: “What Is Potassium?”
- National Organization for Rare Disorders: “Hypokalemia”
- Kaiser Permanente: “Potassium Gluconate 595 mg (99 mg) Tablet”
- National Center for Biotechnology Information: “Potassium Chloride”
- Office of Dietary Supplements: “Potassium”
- Mayo Clinic: “Potassium Citrate (Oral Route)”
- National Library of Medicine: “Phosphorus in Diet”
- American College of Cardiology: “Potassium Chloride”
- National Kidney Foundation: “What Is Hyperkalemia?”
- Journal of Intensive Care Medicine: "Potassium Abnormalities in a Pediatric Intensive Care Unit: Frequency and Severity"