Potassium supplements

Potassium supplements are not a casual health hack. They are a medical intervention for specific, documented deficiencies.

The evidence here shows potassium works as a real treatment when you actually need it. A pregnant woman with severe hyperemesis and a potassium level of 2.0 mEq/L developed rhabdomyolysis and kidney problems, and oral potassium chloride brought her back to normal [1]. A child who got bentonite clay (which binds potassium) dropped to 0.9 mEq/L and needed emergency potassium to survive [2]. These are clear rescue scenarios.

The blood pressure data is real but modest. A 12-week trial in Chinese adults with mild hypertension found potassium supplements (60 mmol/day) lowered systolic pressure by about 5 mmHg more than placebo [4]. Another trial in people at moderate cardiovascular risk found a similar 5.3 mmHg drop in brachial systolic pressure [6]. But the effect is not universal. One double-blind trial in mild hypertension found the blood pressure drop lost statistical significance after adjusting for baseline differences [3]. And the same trial that showed a blood pressure drop also found that potassium increased plasma renin activity and aldosterone [6], which is the body pushing back against the change.

There is a real risk here that nobody talks about. In a study of heart failure patients, having serum potassium outside the middle range was linked to much higher risk of cardiovascular events. The hazard ratios were 3.56 for low potassium and 4.04 for high potassium compared to the middle quartile [5]. That is a U-shaped curve. Too little is bad, too much is worse. The safe range is narrow.

The bone density data is interesting but comes from a single trial using potassium citrate, not potassium chloride [7]. That trial found a 1.7% increase in lumbar spine bone density over 24 months. But the study was funded by a manufacturer of potassium citrate products, and the effect was on a surrogate endpoint, not on actual fracture rates.

The bottom line: potassium supplements help people with documented deficiency or high blood pressure on a high-sodium diet, but the benefit is modest and the risk of pushing potassium too high is real and dangerous.

My call: do not take potassium supplements without a blood test showing you are low. If you have hypertension, try getting potassium from food first. If you are on a thiazide diuretic, the evidence suggests potassium loss drives the diabetes risk from that drug [8], so monitoring is essential. Confidence: moderate. The blood pressure trials are decent but small, the safety data on hyperkalemia is thin, and the long-term effects on hard outcomes like heart attack or death have not been studied in a randomized trial.