If you take a blood pressure medicine such as lisinopril or losartan, ask your clinician or pharmacist before you switch to a potassium-based salt substitute. Lower-sodium salt substitutes replace some of the sodium chloride with potassium chloride, and these medicines nudge your body toward holding on to potassium. For most adults with healthy kidneys the swap is a good one: in a large trial it lowered rates of stroke and death. The risk sits with people whose kidneys cannot clear extra potassium or who already take something that raises it, and a recent blood test is the easiest way to know which group you are in.
The peptide hormone behind the warning
Lisinopril and similar drugs, known as ACE inhibitors, block the step that produces angiotensin II, an eight-amino-acid peptide hormone cut from a larger blood protein. The UniProt record for angiotensinogen describes angiotensin II as a potent blood vessel tightener that also signals the adrenal glands to release aldosterone, a hormone that shapes how the kidneys handle salt and water.
The Zestril (lisinopril) prescribing information spells out the consequence: less angiotensin II means less aldosterone, which may cause a small rise in blood potassium. Losartan belongs to a related class, angiotensin II receptor blockers, which work on the same hormone system by blocking angiotensin II’s receptor. On its own that rise is usually modest. Add a steady extra supply of potassium from a salt shaker, and in some people it can climb too high.
What the drug labels and the WHO say
The lisinopril label lists risk factors for high potassium as kidney impairment, diabetes, and use of potassium-sparing diuretics, potassium supplements or potassium-containing salt substitutes, and it advises periodic potassium checks. It tells clinicians to warn patients not to use those salt substitutes without consulting their physician. MedlinePlus gives the same advice for lisinopril and losartan.
In January 2025 the World Health Organization issued a guideline suggesting that adults who use table salt switch to lower-sodium, potassium-containing substitutes, a conditional recommendation. The guideline’s scope excludes people with kidney impairment or other conditions that might compromise potassium excretion, such as those taking potassium-sparing diuretics or potassium supplements, and it does not apply to children or pregnant women. It also notes that the trials it relied on excluded people with kidney disease or those using potassium-sparing medicines, so they say little about those groups.
What the big trial showed, and who it left out
The Salt Substitute and Stroke Study, published in the New England Journal of Medicine in 2021, randomly assigned 600 villages in rural China to regular salt or a substitute that was 75% sodium chloride and 25% potassium chloride. Among nearly 21,000 people who had a history of stroke or were 60 or older with high blood pressure, the substitute group had lower rates of stroke, major cardiovascular events and death over almost five years. Serious problems attributed to high potassium were not significantly more common.
A 2026 review in Current Opinion in Cardiology puts that reassurance in context: high potassium is uncommon in people with normal kidney function, but there is strong concern in people with moderate to advanced chronic kidney disease or on potassium-sparing diuretics, and combining a potassium-rich diet with drugs that block this hormone system can cause high potassium in people with kidney disease.
Before you switch
Bring the container or a photo of its label to your next appointment or pharmacy visit and ask three things: whether your recent blood work included potassium and kidney function, whether any of your other medicines raise potassium, and whether a potassium-based substitute is reasonable for you.
MedlinePlus notes that high potassium often causes no symptoms, which is why blood tests matter. When symptoms do occur they can include chest pain, trouble breathing, nausea or vomiting, palpitations, and a slow, weak or irregular pulse. MedlinePlus advises contacting your provider right away for vomiting, palpitations, weakness or difficulty breathing.
By The Everyday Brief · AI-assisted editorial. Drafted with AI research assistance; claims checked against the linked sources (fetched 2026-10-06 PT). Not medical advice.
Sources
- DailyMed: Zestril (lisinopril) prescribing information
- MedlinePlus (U.S. National Library of Medicine): Lisinopril
- MedlinePlus (U.S. National Library of Medicine): Losartan
- World Health Organization: Use of lower-sodium salt substitutes, WHO guideline (2025)
- Neal B, et al. Effect of salt substitution on cardiovascular events and death. New England Journal of Medicine, 2021.
- Patel P, Palmer BF, Lange RA. Sodium reduction and salt substitutes: impact on blood pressure and recurrent stroke. Current Opinion in Cardiology, 2026.
- MedlinePlus (U.S. National Library of Medicine): High potassium level
- UniProt: Angiotensinogen, including angiotensin II (P01019)