Potassium
Supplements · Minerals · Supplement, Typed Supps
An electrolyte most people genuinely do not get enough of.
Stage by stage
- Intake (Tablet or powder): Absorbed efficiently throughout the small intestine.
- Small intestine (Efficient absorption): Absorbed efficiently throughout the small intestine.
- Cells (Nerve and muscle signalling): Moves in and out of cells, critical for nerve signalling and muscle contraction, including the heart.
- Kidneys (Tightly regulated): Balanced closely by the kidneys, which excrete any excess.
What the evidence supports
- Lowering blood pressure, especially against a high-sodium diet — strong evidence. Higher potassium intake consistently reduces blood pressure in meta-analyses, and is endorsed by WHO and dietary guidelines.
- Reducing stroke risk — moderate evidence. Supported by observational data and some trial evidence, largely tied to the blood-pressure effect.
- Preventing or relieving muscle cramps — limited evidence. Commonly assumed, but the evidence is weak in people who are not actually deficient.
- Getting the benefit from supplements rather than food — limited evidence. Most evidence comes from dietary potassium; over-the-counter supplements are capped low (99 mg per tablet in many markets) for safety, so food remains the main route.
Typical dose
99 mg per tablet in the US, where supplement doses are capped; food is the realistic route
Upper limit: No UL for healthy adults from food. Supplemental potassium is capped precisely because concentrated doses are risky
Timing
Supplement doses are capped lower than prescription doses for safety.
Time to effect
- Hours: Blood levels shift.
- Ongoing: Broader effects with consistent intake.
Medication interactions
- ACE inhibitors (e.g. ramipril, lisinopril): Reduce urinary potassium loss, so added potassium can push levels dangerously high (hyperkalaemia). (high)
- Angiotensin receptor blockers (ARBs): Like ACE inhibitors, they raise potassium retention and hyperkalaemia risk. (high)
- Potassium-sparing diuretics (e.g. spironolactone, amiloride): Directly reduce potassium excretion; combining with supplements risks hyperkalaemia. (high)
- NSAIDs: Can reduce potassium excretion, adding to hyperkalaemia risk, especially with reduced kidney function. (moderate)
Common myth
“You can’t get too much potassium from food.” In reality: True from food alone, but concentrated supplements can raise blood potassium to dangerous levels for some people.
Food sources
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