Potassium deficiency affects a surprisingly wide range of people, from those taking common prescription medications to anyone whose diet falls short of the recommended 3,400 mg per day for men or 2,600 mg for women. Most Americans don’t hit those targets. But certain groups face a much higher risk because of how their bodies handle potassium: losing too much through the kidneys, the gut, or sweat, or failing to absorb enough from food.
People Taking Certain Medications
Medications are one of the most common causes of potassium depletion, and the list extends well beyond the usual suspects. Diuretics (water pills) are the best-known culprits. Drugs like furosemide, hydrochlorothiazide, chlorthalidone, and bumetanide all force the kidneys to excrete more fluid, and potassium goes with it. If you take any type of diuretic for blood pressure or fluid retention, your doctor has likely already flagged this risk.
But several other drug classes also drain potassium. Corticosteroids like prednisone and hydrocortisone increase potassium excretion through the kidneys. Certain antibiotics, including penicillin-type drugs and the antifungal amphotericin B, do the same. Laxatives cause potassium loss through the stool, which makes regular or heavy laxative use a significant risk factor. Even inhaler medications used for asthma, such as albuterol and salmeterol, can temporarily shift potassium out of the bloodstream and into cells, lowering circulating levels. High caffeine intake works through the same mechanism.
The more of these medications you combine, the greater the cumulative effect. Someone on both a diuretic and a steroid, for example, faces compounded risk.
People With Digestive Conditions
Any condition that causes chronic diarrhea or poor nutrient absorption puts you at risk. Inflammatory bowel diseases like Crohn’s disease and ulcerative colitis are prime examples. The intestinal damage in these conditions increases fecal potassium loss, sometimes significantly. Crohn’s disease affecting the terminal ileum is particularly problematic because it can trigger bile acid diarrhea, which further disrupts electrolyte balance.
Celiac disease, chronic infections, and other malabsorption disorders reduce the gut’s ability to pull potassium from food before it passes through. Frequent vomiting, whether from a medical condition or an eating disorder like bulimia, also depletes potassium. The loss isn’t just from stomach contents; vomiting triggers the kidneys to waste additional potassium in response to the resulting chemical shifts in the blood.
People With Hormonal Imbalances
Your adrenal glands produce a hormone called aldosterone that tells the kidneys to hold onto sodium. The tradeoff is that every time the kidneys reabsorb sodium, they push potassium and hydrogen ions out into the urine to maintain electrical balance. In a condition called hyperaldosteronism, the adrenal glands overproduce aldosterone, creating a constant drain on potassium stores. This leads to low potassium levels, and sometimes that persistent, unexplained drop in potassium is what leads doctors to discover the hormone problem in the first place.
Cushing’s syndrome, where the body produces excess cortisol, has a similar effect. Cortisol at high enough levels mimics aldosterone’s action in the kidneys, pushing potassium out.
People Who Are Low in Magnesium
This is one of the most overlooked risk factors. Magnesium deficiency doesn’t just coexist with potassium deficiency; it actively causes it. Inside the kidney, magnesium normally acts as a brake on potassium-secreting channels in the tubules. When magnesium drops, that brake releases, and the kidneys start dumping potassium into the urine at an accelerated rate.
What makes this particularly frustrating is that potassium supplements alone won’t fix the problem. The potassium deficiency becomes “refractory,” meaning it resists correction until magnesium levels are restored first. Since magnesium deficiency is itself common (especially in older adults, people with diabetes, and heavy drinkers), this creates a hidden chain reaction that many people never connect.
People Who Drink Heavily
Potassium deficiency occurs in nearly 50% of people with chronic alcohol use disorder. The reasons stack up: alcohol acts as a diuretic, increasing kidney potassium loss. Heavy drinkers often eat poorly, taking in less potassium from food. Alcohol also depletes magnesium, which triggers the refractory potassium wasting described above. Vomiting and diarrhea associated with heavy drinking add gastrointestinal losses on top of the renal ones.
Even moderate but consistent drinking over time can gradually erode potassium levels, especially if combined with a diet low in fruits, vegetables, and other potassium-rich foods.
Athletes and People Who Sweat Heavily
Sweat contains potassium at concentrations of roughly 2 to 8 millimoles per liter, a range similar to what’s found in blood plasma. For casual exercisers, this loss is modest and easily replaced through normal eating. But endurance athletes, outdoor laborers, or anyone training intensely in heat can lose multiple liters of sweat per hour. At that volume, potassium losses add up.
The risk compounds when athletes rely on sports drinks that prioritize sodium replacement but contain relatively little potassium, or when they restrict calories during training. The relationship between sweat rate and potassium concentration is inverse: as you sweat faster, the concentration per liter actually tends to decrease. Still, the sheer volume of fluid lost during prolonged activity means total potassium loss can be significant.
People on Restrictive or Low-Calorie Diets
Low-calorie diets are recognized as a cause of urinary potassium wasting. When caloric intake drops sharply, the body’s insulin levels fall, which shifts potassium handling in the kidneys. People following very-low-carb diets face additional risk because the initial water weight loss mimics a diuretic effect, flushing electrolytes including potassium. Eating disorders involving caloric restriction, purging, or laxative misuse combine multiple mechanisms of loss at once.
Even without extreme restriction, a diet built around processed foods and low in whole fruits, vegetables, beans, and dairy will likely fall short of the daily adequate intake. Potassium isn’t added to most processed foods the way sodium is, so the more packaged food dominates your diet, the wider the gap becomes.
Older Adults
Aging increases potassium deficiency risk from several directions at once. Older adults are more likely to take diuretics, laxatives, and other medications that deplete potassium. Kidney function naturally declines with age, which can alter electrolyte handling. Appetite often decreases, reducing dietary potassium intake. And conditions like diabetes, heart failure, and chronic kidney disease, all more common in older populations, either directly affect potassium balance or require medications that do.
Magnesium deficiency is also more prevalent in older adults, compounding the problem through the refractory mechanism. This makes the over-65 population one of the most consistently at-risk groups, even when no single dramatic risk factor is present.
People With Kidney Tubule Disorders
Certain inherited or acquired kidney conditions cause the tubules to leak potassium regardless of dietary intake. Bartter syndrome and Gitelman syndrome are genetic disorders that mimic the effect of being on a permanent diuretic, causing ongoing potassium and salt wasting. Renal tubular acidosis, another tubular disorder, disrupts the kidney’s acid-base handling and leads to excess potassium excretion. These conditions are relatively rare but cause persistent, sometimes severe, potassium deficiency that requires ongoing management.