Health

7 Low Potassium Symptoms, Causes & How To Treat Hypokalemia 2025

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Potassium[1] is an electrolyte, which is a mineral that carries an electric charge when dissolved in your body’s fluids. You need potassium for your muscles, nerves, heart, and cells to function properly. Potassium also plays a role in digestive and bone health.

Low potassium levels, also called hypokalemia, occur when the concentration of potassium in your blood is too low for normal functioning. You should get enough potassium from your diet, but certain medications, chronic diarrhea, and vomiting can increase the risk of low potassium levels.

Think you have a potassium deficiency? If so, it’s important to know the low potassium symptoms to look out for. In this article, we’ll also cover what causes a potassium deficiency, how to treat low potassium levels, and the most common sources of potassium.

What Are The Symptoms Of Low Potassium?

Here are the most commonly reported low potassium symptoms[1]:

  • Muscle Cramps Or Twitches
  • Weakness And Fatigue
  • Constipation
  • High Blood Pressure
  • Abnormal Heart Rhythms
  • Excessive Thirst And Urination
  • Breathing Problems

7 Low Potassium Symptoms

Here are the seven most common symptoms of a potassium deficiency or hypokalemia:

Muscle Cramps Or Twitches

Potassium is needed for your muscle cells[2] to contract and relax properly.

That’s why low potassium levels can cause muscle symptoms, especially muscle cramps and muscle twitches, which are sudden, uncontrollable muscle contractions.

Muscle twitches might happen in mild hypokalemia, whereas muscle cramps[3] are less common and might only occur in severe hypokalemia.

A more serious symptom of severe hypokalemia can be muscle paralysis.

Weakness And Fatigue

As potassium helps control muscle contractions, low blood potassium levels can cause weaker muscle contractions.[2] This can make you feel weak.

What’s more, a potassium deficiency might impair insulin production,[4] leading to high blood sugar levels and less glucose being shuttled to your cells to produce energy, making you feel fatigued.

Constipation

Digestion relies on the contractions of the smooth muscle[5] that lines the digestive tract. As low potassium levels can weaken muscle contractions, food will move through your digestive tract more slowly. This might cause digestive problems such as constipation or bloating.

However, constipation is only usually a symptom of severe hypokalemia.

High Blood Pressure

The balance of electrolytes in the bloodstream is crucial for maintaining healthy blood pressure levels. The important electrolytes include potassium, sodium, chloride, calcium, magnesium, and phosphate.

You probably already know that consuming too much salt or sodium can lead to high blood pressure. But did you know that a low intake of potassium relative to sodium[6] can have the same effect?

Adequate potassium levels are important because they help your kidneys filter out excess sodium and balance blood pressure.[7] Without enough potassium, you will reabsorb too much sodium back into your blood.

Abnormal Heart Rhythms

The heart is a big muscle, so it makes sense that low potassium levels can also negatively affect heart contractions.

Low potassium levels are associated with an increased risk of irregular heartbeat,[8] especially in the elderly population. Hypokalemia is also a risk in those with heart failure[9] due to treatment with diuretics, which can increase the risk of sudden cardiac death.

If you notice any changes in your heart rhythm, you should seek immediate medical attention because it can be a sign of a serious condition.

Excessive Thirst And Urination

Low potassium levels might impair kidney function,[10] leading to increased urination. Excessive urination, also called polyuria, can be triggered by low potassium levels because potassium is crucial for kidney function and balancing your body’s fluid levels.

Unfortunately, frequent urination also further increases the risk of potassium deficiency. It’s therefore important to contact your doctor if you notice changes in your urination frequency that don’t go away after a few days.

Breathing Problems

Severe hypokalemia can cause breathing difficulties because the diaphragm — the muscle that controls the lungs — needs potassium to function properly.

Severe hypokalemia can be fatal if you suffer from muscle paralysis[11] and your lungs stop working entirely. Studies show that those admitted to hospitals with respiratory failure[12] were more likely to have altered potassium levels compared to the general population.

Causes Of Potassium Deficiency

Low potassium levels are usually due to excessive loss of potassium from the digestive tract, rather than consuming too little potassium from the diet.

The main causes of low potassium[13] levels are:

  • Eating disorders, especially bulimia nervosa.
  • Alcohol use disorder.
  • Excessive sweating.
  • Diuretics.
  • Kidney disorders, such as chronic kidney disease.
  • Low magnesium levels.
  • Certain medications, such as insulin, some antibiotics, and corticosteroids.
  • Chronic diarrhea.

In rare cases, a potassium deficiency might be caused by eating a diet low in potassium. For example, a low-carb ketogenic diet used to treat epilepsy in children can increase the risk of metabolic acidosis[14] caused by a potassium deficiency.

This is because many high-potassium foods are also high in carbohydrates, which one cannot eat on a ketogenic diet.

Is Low Potassium A Sign Of Cancer?

Not necessarily, although some cancer patients may have low potassium levels due to vomiting or reduced food intake.

How To Treat Hypokalemia?

You must seek immediate medical attention if you or someone else exhibits symptoms of severe hypokalemia. If you have been vomiting or had diarrhea for more than 24–48 hours, you should also seek medical care to prevent hypokalemia due to the extreme loss of fluids.

For milder cases, before treating hypokalemia, you will need a proper diagnosis.

How Is Hypokalemia Diagnosed?

If a potassium deficiency is suspected, your healthcare provider will order a blood test to assess the amount of potassium in the blood.

For a healthy adult, your blood potassium level[1] should be between 3.5–5.2 millimoles per liter. A blood potassium level of between 3–3.5 millimoles per liter is considered a mild potassium deficiency, while anything lower than 3 millimoles per liter is considered a severe potassium deficiency, i.e., severe hypokalemia.

Once you have a diagnosis, your healthcare provider will need to assess the cause of the deficiency. Further blood tests can support this process, such as a blood test for kidney function and an electrolyte balance blood test.

Apart from blood tests, you might also have a urine analysis to check the concentration of potassium in your urine, and an electrocardiogram — also called an ECG — which measures your heart rhythm to check for arrhythmias.

How Is Hypokalemia Treated?

Treating acute hypokalemia is usually easy. If you have mild hypokalemia, you might be prescribed oral potassium supplements. However, if you have a severe potassium deficiency, your doctor might give you intravenous potassium directly into your bloodstream.

However, you will also need to treat the underlying cause of your hypokalemia to prevent it from reoccurring. If it is likely caused by medications, your doctor might try switching the brand or type of medication. If you are taking diuretics, you might be put on a higher dose of oral potassium supplements to replace the extra loss of potassium via the urine.

On the other hand, if your hypokalemia is caused by a kidney disorder, eating disorder, or alcohol use disorder, this will be treated separately.

Should You Take Potassium Supplements?

Oral potassium pills are usually in the form of potassium chloride. For the majority of the population, potassium supplements should not be necessary. You should be able to get all the potassium you need from a healthy, varied diet.

However, some people might need to take a potassium supplement if low potassium levels are caused by a kidney disorder or medications such as diuretics.

Also, anecdotal evidence suggests that if you’re following a ketogenic diet, which is a very low-carbohydrate, high-fat diet, you might need to supplement with potassium as many potassium-rich foods are not allowed on this diet. However, interestingly, studies have found no changes in potassium levels[15] in those following a ketogenic diet.

Finally, those with high blood pressure might benefit from supplementing potassium, as there’s a link between supplementing potassium and reduced high blood pressure.[4]

However, this could be because increasing potassium may decrease sodium intake by default, so reducing your salt intake could also help.

However, make sure you speak to your doctor about the proper dose of potassium to take, as too much potassium can increase the risk of cardiovascular problems.[8]

Sources Of Potassium

To help prevent a potassium deficiency, you should eat a diet rich in potassium.

The current recommended Daily Value for potassium[16] is 4,700 milligrams, which was recently raised from 3,500 milligrams by the Food and Drug Administration.

The best food sources of potassium include:

  • Dark leafy greens — especially beet greens[17] with 1,310 milligrams per cup cooked.
  • Fish — especially salmon[18] with 746 milligrams per six-ounce fillet.
  • Beans — especially white beans[19] with 1,004 milligrams per cup cooked.
  • Avocado[20] — 975 milligrams per medium avocado.
  • White potatoes[21] — 926 milligrams per medium potato.
  • Acorn squash[22] — 896 milligrams per cup cooked.
  • Milk[23] — 374 milligrams cup.
  • White button mushrooms[24] — 555 milligrams per cup cooked.
  • Bananas[25] — 375 milligrams per medium-sized banana.
  • Tomatoes[26] — 193 milligrams per 100 grams.
  • Cantaloupe[27] — 245 milligrams per cup.

The Takeaway

If you have low potassium symptoms, such as heart palpitations, muscle weakness, or constipation, you might have mild hypokalemia or low potassium levels. In severe cases, hypokalemia can cause serious heart arrhythmias and even muscle paralysis.

Potassium supplements should be able to treat most cases of mild hypokalemia, but you might need an intravenous infusion of potassium if you have severe hypokalemia.

If there’s not an underlying medical condition causing hypokalemia, you should be able to get enough potassium by eating foods rich in potassium such as leafy greens, beans, and cantaloupe.

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