Potassium is an essential mineral and electrolyte that plays a critical role in many body functions. For example, potassium is required to regulate your heartbeat and blood pressure, proper nerve conduction, protein synthesis, glycogen levels (a storage form of glucose), and muscle contraction.
Potassium is found naturally in most fruits, vegetables, legumes, and seeds. In healthy individuals with normal kidney function, abnormally low or high blood levels of potassium are rare.
This article describes the most common reasons people take potassium supplements, the recommended daily amounts, and the possible side effects.
Dietary supplements are not regulated in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. When possible, choose a supplement that has been tested by a trusted third party, such as USP, ConsumerLabs, or NSF.
However, even if supplements are third-party tested, that doesn’t mean that they are necessarily safe for everyone or effective in general. It is important to talk to your healthcare provider about any supplements you plan to take and to check in about any potential interactions with other supplements or medications.
Supplement Facts
Active ingredient(s): Potassium chloride, citrate, phosphate, aspartate, bicarbonate, or gluconate
Alternate name(s): Potassium salt, potassium chloride salt
Legal status: Available over the counter (OTC)
Suggested dose: 99 milligrams (mg)
Safety considerations: High doses may cause gastrointestinal side effects, kidney damage, and small bowel lesions, and may interact with medications including ACE inhibitors and potassium-sparing, loop, and thiazide diuretics
Uses of Potassium
Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or doctor. No supplement is intended to treat, cure, or prevent disease.
Some studies suggest that higher intakes of potassium may reduce the risk of diseases like high blood pressure and stroke, osteoporosis, kidney stones, and diabetes. Some of these claims are better supported by research than others.
Blood Pressure and Stroke
Because of potassium’s relationship to sodium, which regulates fluid and plasma volume, some research has focused on its ability to lower blood pressure and stroke risk.
In an older but memorable 2006 clinical trial, Dietary Approaches to Reduce Hypertension (DASH), published in the New England Journal of Medicine, researchers evaluated whether a diet rich in fruits, vegetables, low-fat dairy foods, and reduced saturated and total fat could lower blood pressure.1
Many people came to call it “the DASH diet,” an eating pattern that is higher in potassium and lower in sodium. Researchers fed participants a controlled diet for three weeks. Then they randomized people into a standard American diet (control), a fruit and vegetable diet, or a combination diet (the DASH diet) for eight weeks.
Those on the DASH diet lowered their systolic blood pressure (pressure when blood is ejected into arteries) by an average of 5.5 mmHg and diastolic blood pressure (pressure in arteries between beats) by 3.0 mmHg.
More recently, a 2017 study published in the International Journal of Cardiology evaluated the effect of potassium supplements on hypertension (high blood pressure).2 The systematic review and meta-analysis found that potassium supplementation decreased systolic blood pressure by 4.48 mmHg and diastolic blood pressure by 2.96 mmHg.
In addition, a 2013 review in the British Medical Journal evaluated whether increased potassium intake could affect heart disease risk factors and disease, including stroke.3 Researchers looked at 22 randomized controlled trials and 11 cohort studies. In addition to reduced blood pressure, researchers found that increased potassium intake was associated with a lower risk of stroke, with higher intakes reducing stroke risk by 24%.
FDA-Approved Claim
The FDA has approved the following health claim relating to potassium: “Diets containing foods that are good sources of potassium and low in sodium may reduce the risk of high blood pressure and stroke.”4
Bone Density
Since potassium is alkaline (meaning it neutralizes acids), some scientists have evaluated whether consumption of potassium-rich foods and supplements could reduce the net acid content in a person’s diet and preserve calcium in bones.5
However, research on this subject is mixed. An older 2008 study in the American Journal of Clinical Nutrition measured the effects of potassium citrate supplementation and increased fruit and vegetable consumption in 276 postmenopausal people. It found that after two years of potassium citrate supplementation, bone turnover was not reduced, and there was no increase in bone mineral density.6
By contrast, a more recent 2018 study published in Nutrients evaluated whether potassium could decrease bone loss in women with osteopenia (low bone density). The randomized, double-blind, placebo-controlled, parallel-group study included 310 postmenopausal participants.
It found that potassium citrate supplementation improved the beneficial effects of calcium and vitamin D in osteopenic women with a potassium deficit. This study suggests that potassium’s ability to increase bone mineral density may rely on the intake of calcium and vitamin D, nutrients essential for bone health. However, more research is needed to confirm or disprove this relationship.7
Kidney Stones
Abnormally high urinary calcium (hypercalciuria) increases the risk of developing kidney stones. In addition, diets that are high in protein and low in potassium may contribute to increased stone formation. Therefore, some studies have examined whether potassium could reduce kidney stone risk.
In a 2016 study published in the Clinical Journal of the American Society of Nephrology, researchers examined the relationship between protein and potassium intake on kidney stones.8 They found that higher dietary potassium was associated with a statistically significant and considerable reduction in kidney stone risk in all groups. They also found that the type of protein consumed may also affect kidney stone risk—specifically, vegetable protein reduced risk compared to animal protein.
In addition, a 2015 review in Cochrane evaluated the role of citrate salts (such as potassium citrate) in preventing and containing calcium-containing kidney stones.9 In seven studies with 477 participants, researchers found that citrate significantly reduced stone size compared to placebo or no intervention. In addition, new stone formation was significantly lower in the citrate group than in the control group.
Blood Glucose and Diabetes
Since potassium is needed for insulin secretion from the pancreas, some research has focused on its relationship to glucose (blood sugar) levels and diabetes.
For example, a 2015 study evaluated the impact of potassium on glucose levels in older adults.10 Researchers found a significant association between lower dietary potassium intake, reduced insulin sensitivity, and increases in insulin secretion.
Similarly, a 2016 clinical trial evaluated potassium levels with glucose and diabetes risk over eight years.11 Researchers found that compared to those with higher potassium levels (≥4.5mmol/L), those with lower levels (<4.0mmol/L) had significantly higher fasting glucose.
In addition, researchers found an inverse association between serum and dietary potassium and diabetes risk.
Potassium Deficiency
Some people may develop a potassium deficiency when intakes are lower over time than recommended levels, they have a specific risk factor for lower than normal levels, or there is a particular reason they are unable to digest or absorb potassium.
What Causes a Potassium Deficiency?
Intakes that are less than the recommended amounts may result in potassium deficiency. When intakes are lower than your body needs, it can lead to health complications, including increased blood pressure and the risk of developing kidney stones.
In addition to low dietary intakes, some other things may contribute to potassium deficiency, including:5
Diarrhea
Vomiting
Diuretic use
Laxative overuse
Pica (eating non-nutritive substances, like clay)
Heavy sweating
Dialysis (a medical procedure to cycle blood when kidneys can not)
Inflammatory bowel disease (IBD)
Some people are more at risk of developing a potassium deficiency, including:5
Those with i
Those who take diuretics or laxatives
People with pica
How Do I Know If I Have a Potassium Deficiency?
You may not even know if you have a mild potassium deficiency. However, more severe deficiency can result in hypokalemia, when blood serum levels fall below 3.6 mmol/L. Mild hypokalemia may produce symptoms such as:12
Constipation
Fatigue
Muscle weakness
Malaise (overall feeling unwell)
More serious hypokalemia may produce the following symptoms:12
Polyuria (excessive urination)
Encephalopathy (disease affecting brain function) in people with kidney disease
Glucose intolerance
Muscular paralysis
Poor respiration
Cardiac arrhythmias (irregular heartbeat)
Severe hypokalemia is life-threatening due to its effect on the heart and breathing. Fortunately, severe cases rarely occur because of inadequate potassium intake alone. However, if you notice any of these symptoms, it's best to have them evaluated.
What Are the Side Effects of Potassium?
Your provider may recommend you take potassium for deficiency or to lower your risk of some health conditions, like kidney stones. However, consuming a supplement like potassium may have potential side effects. These side effects may be common or severe.
If you're increasing your intake of fruits and vegetables, you will be increasing your intake of potassium and fiber. When increasing fiber, it's essential to do so slowly and gradually to prevent gas and bloating. In addition, make sure to drink adequate amounts of fluids. Neglecting to hydrate appropriately can result in constipation.13
Common Side Effects
Common side effects of potassium supplementation include:
14
Diarrhea
Nausea
Stomach pain or discomfort or mild gas
Vomiting
Severe Side Effects
More rarely, potassium supplements can result in severe side effects. These most often occur in people who have high intakes and impaired kidney function or who take certain medications like ACE inhibitors and potassium-sparing diuretics.12
Severe side effects include:14
Confusion
Cold, pale, or gray skin
Stomach pain or bulging
Black stools
Numbness or tingling in the hands, feet, or lips
Unexplained anxiety
Unusual tiredness or weakness
Weakness or heaviness in the legs
Call your healthcare provider as soon as possible if you experience severe side effects.
Precautions
People with certain health conditions or taking some medications are at greater risk of severe side effects and drug interactions from potassium. This includes individuals with abnormal kidney function and those on potassium-sparing medications or ACE inhibitors, typically used for treating high blood pressure. A complete list of medication interactions is included below.
Dosage: How Much Potassium Should I Take?
Always speak with a healthcare provider before taking a supplement to ensure that the ingredients and dosage are appropriate for your individual needs.
The National Academies of Sciences, Engineering, and Medicine (NASEM) recommends the following adequate intakes (AIs) for potassium:12
400 mg (infants through 6 months)
860 mg/day (infants 7-12 months)
2,000 mg/day (1-3 years)
2,300 mg/day (4-8 years)
2,500 mg/day (males 9-13 years)
2,300 mg/day (females 9-13 years)
3,000 mg/day (males 14-18 years)
2,300 mg/day (females 14-18 years)
3,400 mg/day (males 19+ years)
2,600 mg/day (females 19+ years)
2,600 (under 18) or 2,900 (18+ years) during pregnancy
2,500 (under 18) or 2,800 (18+ years) during lactation
What Happens If I Take Too Much Potassium?
To avoid toxicity, be aware of the appropriate dosage (above). NASEM has not established an upper limit for potassium. However, people with impaired urinary potassium excretion due to health conditions like kidney disease or certain medications should be aware of potassium supplementation's potential toxicity.
If you fall into these categories and consume more potassium than your healthcare provider recommends, you may want to seek medical attention. In addition, if you notice any of the severe side effects (above), seek emergency medical care.
Interactions
Some medications can interact with potassium supplements. These include:12
ACE inhibitors
Angiotensin receptor blockers (ARBs)
Potassium-sparing diuretics, such as Midamor (amiloride) and Aldactone (spironolactone)
Loop diuretics, such as Lasix (furosemide) and Bumex (bumetanide)
Thiazide diuretics, such as Diuril (chlorothiazide) and Zaroxolyn (metolazone)
These medications can impact potassium in dangerous ways. Therefore, experts recommend monitoring potassium levels in people who take these drugs.
It is essential to carefully read the ingredient list and nutrition facts panel of a supplement to know which ingredients are included and in what amounts. In addition, please review the supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications.
How To Store Potassium
Store fresh fruits and vegetables using best practices for maximizing their freshness. Storage guidelines differ depending on the fruit or vegetable. For example, some should be refrigerated while others, such as tomatoes, should be left at room temperature.
Store potassium supplements in a cool, dry place. Keep potassium away from direct sunlight. Discard after one year or as indicated on the packaging.