Higher potassium intake lowers blood pressure, roughly 4 to 6 mmHg systolic at higher intakes in trial meta-analyses, but food sources are the preferred route and supplements carry real cautions.
The physiology is a seesaw with sodium: more potassium helps the kidneys shed sodium and eases vessel tone, with the biggest effects in people with hypertension on high-sodium diets. Why food beats pills: US over-the-counter potassium is capped at 99 mg per dose for gut-safety reasons, so a potato or a cup of beans delivers multiples of what any legal supplement can. The danger zone is specific and worth memorizing: kidney disease, ACE inhibitors, ARBs, and potassium-sparing diuretics (spironolactone) all impair potassium excretion, and adding supplements or potassium salt substitutes on top can push levels toward dangerous heart rhythms. That combination requires lab monitoring, not guesswork. For everyone else, the daily pattern is the treatment: potassium-rich foods at most meals, less sodium, and let the seesaw work.
What to do
Common questions
Can potassium supplements lower blood pressure?
Yes, with an important food-first framing. Potassium and sodium work as opposing levers: potassium helps your kidneys excrete sodium and relaxes blood vessel walls. A dose-response meta-analysis of randomized trials (Proceedings of the Nutrition Society, 2020) found higher potassium intake lowered blood pressure in a graded way, with reductions around 4 to 6 mmHg systolic at higher intakes, and effects were largest in people with hypertension eating high-sodium diets. But the evidence base is mostly about potassium intake, not pills, and the major guidelines steer people toward food sources: potatoes, bananas, beans, yogurt, leafy greens, oranges, and avocados, which also happen to be DASH-diet staples. Supplements come with a real caution list. Over-the-counter potassium pills are limited to 99 mg per dose in the US (a safety cap, because concentrated potassium can injure the gut lining), so food delivers far more than any legal pill. And potassium supplements become dangerous with impaired kidneys or alongside ACE inhibitors, ARBs, or potassium-sparing diuretics like spironolactone, because potassium can climb to heart-rhythm-threatening levels. If you take any of those medications, do not add potassium supplements or potassium-based salt substitutes without your clinician checking levels first. The clean play for most people: eat potassium-rich food daily and cut sodium; that pairing does the heavy lifting.