Potassium as a dietary supplement

• PRINCIPAL PROPOSED USE: Hypertension

DEFINITION: Natural substance essential for health and promoted as a dietary supplement for specific health benefits.

Overview

Potassium is a mineral found in many foods and supplements. Pure potassium is not seen in health food stores or pharmacies because it is a highly reactive metal that bursts into flames when exposed to water. The potassium that is eaten or taken as a supplement is composed of potassium atoms bound to other nonmetallic substances.

Potassium is one of the major electrolytes in the body, along with sodium and chloride. Potassium and sodium work in a reciprocal balance: When the level of one goes up, that of the other goes down. Together, the three dissolved minerals play an intimate chemical role in every function of the body.

Requirements and Sources

Potassium is an essential mineral obtained from many common foods. True potassium deficiencies, called hypokalemia, are rare except in cases of prolonged vomiting or diarrhea or with the use of diuretic drugs. However, in one sense, potassium intake is often inadequate relative to sodium intake. It is probably healthy to consume a minimum of five times as much potassium as sodium (and perhaps fifty to one hundred times as much), but the standard American diet contains twice as much sodium as potassium. Therefore, taking extra potassium may help balance the excess sodium consumed.

Bananas, orange juice, potatoes, avocados, lima beans, cantaloupes, peaches, tomatoes, flounder, salmon, and cod all contain more than 300 milligrams (0.3 grams) of potassium per serving. Other good sources include chicken, meat, and various other fruits, vegetables, and fish.

Over-the-counter potassium supplements typically contain 99 milligrams (0.099 grams) of potassium per tablet. There is some evidence that, of the different forms of potassium supplements, potassium citrate may be most helpful for those with high blood pressure.

Some research indicates that it is also important to get enough magnesium when taking potassium, and limited evidence suggests that adequate magnesium intake may be beneficial; evidence for additional vitamin B₁₂ supplementation is inconclusive.

Therapeutic Dosages

When used by physicians, potassium is usually measured in milliequivalents (meqs) rather than in the more common mg. A typical therapeutic dosage of potassium is between 10 and 20 meq, taken three to four times daily. Potassium supplements are most commonly available in the form of potassium chloride. Other forms include potassium phosphate, citrate, aspartate, bicarbonate, and gluconate.

The National Institutes of Health (NIH) provides adequate intake (AI) levels for potassium intake according to age and sex—from birth to six months (400 milligrams [0.4 grams]), seven to twelve months (860 milligrams [0.86 grams]), one to three years (2,000 milligrams [2 grams]), and four to eight years (2,300 milligrams [2.3 grams]). Boys continue to require 2,300 mmilligrams (2.3 grams) per day from age nine to eighteen and 2,600 milligrams (2.6 grams)per day from age nineteen. Girls ages nine to thirteen require 2,500 milligrams (2.5 grams), ages fourteen to eighteen 3,000 milligrams (3 grams), and over age nineteen, 3,400 milligrams (3.4 grams). Pregnant girls (under eighteen) require 2,600 milligrams (2.6 grams), while pregnant women require 2,900 milligrams (2.9 grams). Lactating girls require 2,500 milligrams (2.5 grams) while lactating women require 2,800 milligrams (2.8 grams)

Therapeutic Uses

The most common use of potassium supplements is to make up for potassium depletion caused by diuretic drugs. These medications are often used to help regulate blood pressure, but by depleting the body of potassium, they may inadvertently make blood pressure harder to control.

There is limited evidence for proposed uses like controlling gout and high blood pressure and limiting kidney stones, heart disease, and stroke.

Scientific Evidence

High blood pressure. According to a review of 33 double-blind studies, potassium supplements can produce a slight but definite drop in blood pressure. However, two large studies found no benefit. The explanation is probably that potassium is only slightly helpful. When a treatment has only a small effect, it is not unusual for some studies to show no effect while others find a modest benefit. Potassium may help only those people who are deficient in this mineral. Evidence suggests that potassium supplements may be most effective for people who eat too much salt. For this reason, the American Heart Association recommends individuals trying to control their blood pressure should ingest 3,500 milligrams (3.5 grams) to 5,000 milligrams (5 grams) of potassium.

Kidney problems. Prescription potassium citrate is used to treat a kidney condition called renal tubular acidosis because it is a urinary alkalinizer. Insufficient evidence exists to confirm its proposed use as a preventative aid or treatment for kidney stones.

Safety Issues

As an essential nutrient, potassium is safe when taken at appropriate dosages. In healthy individuals, excess potassium is usually excreted in urine, but excessive intake can still pose health risks. However, people who have severe kidney disease cannot excrete potassium normally and should consult a physician before taking a potassium supplement. Similarly, persons taking potassium-sparing diuretics (such as spironolactone), ACE inhibitors (such as captopril), or trimethoprim-sulfamethoxazole should not also take potassium supplements except under doctor supervision. Potassium pills can cause injury to the esophagus if they get stuck on the way down, so one should make sure to take them with plenty of water.

Important Interactions

Persons taking loop diuretics or thiazide diuretics may need more potassium. Persons taking ACE inhibitors (such as captopril, lisinopril, and enalapril), potassium-sparing diuretics (such as triamterene or spironolactone), or trimethoprim-sulfamethoxazole should not take potassium except on the advice of a physician.

Bibliography

Gu, D., et al. “Effect of Potassium Supplementation on Blood Pressure in Chinese: A Randomized, Placebo-Controlled Trial.” Journal of Hypertension, vol. 19, no. 7, 2001, pp. 1325–31, doi:10.1097/00004872-200107000-00019. Accessed 21 Dec. 2025.

He, F. J., et al. “Effects of Potassium Chloride and Potassium Bicarbonate on Endothelial Function, Cardiovascular Risk Factors, and Bone Turnover in Mild Hypertensives.” Hypertension, vol. 55, no. 3, 2010, pp. 681–88, doi:10.1161/HYPERTENSIONAHA.109.147488. Accessed 21 Dec. 2025.

“Potassium: Fact Sheet for Consumers.” Office of Dietary Supplements, National Institutes of Health, 22 Mar. 2021, ods.od.nih.gov/factsheets/Potassium-Consumer/. Accessed 21 Dec. 2025.

“Potassium: Fact Sheet for Health Professionals.” Office of Dietary Supplements, National Institutes of Health, 2 June 2022, ods.od.nih.gov/factsheets/Potassium-HealthProfessional/. Accessed 21 Dec. 2025.

“Potassium - Uses, Side Effects, and More.” WebMD, www.webmd.com/vitamins/ai/ingredientmono-851/potassium. Accessed 21 Dec. 2025.

Savica, V., et al. “The Effect of Nutrition on Blood Pressure.” Annual Review of Nutrition, vol. 30, 2010, pp. 365–401, doi:10.1146/annurev-nutr-010510-103954. Accessed 21 Dec. 2025.