A salt substitute is an unusual thing to find on a wellness shelf: a product with randomised controlled trials behind it and a World Health Organization suggestion to use it. The versions in question swap out part of the sodium chloride in table salt for potassium chloride — the 25–40% potassium blends the trials tested — and they are now sold in ordinary supermarkets as “lower-sodium,” “reduced-sodium” or “light” salt.
The reason they matter is arithmetic. Nearly everyone eats more sodium than guidance recommends, and the WHO’s sodium-reduction fact sheet puts the global mean intake for adults at 4,278 mg a day — roughly 11 g of salt — as of 2021. That is more than double the agency’s ceiling of under 2,000 mg of sodium a day, which is under 5 g of salt, or about a teaspoon.
What the guidance actually says
The WHO recommends that adults keep sodium below 2,000 mg a day and that children aged 2–15 scale that down according to their energy needs. It estimates that 1.7 million deaths a year were associated with consuming too much sodium in 2023, and it frames reduction as one of the cheapest public-health buys available: at least US$12 returned for every US$1 spent on scaling up interventions. A 2013 World Health Assembly target called for a 30% relative cut in population salt intake by 2025; the timeline was later extended to 2030.
Inside that guidance sits a specific line about the product itself: if choosing to use table salt, the WHO suggests replacing regular salt with lower-sodium substitutes that contain potassium. It also holds that all salt consumed should be iodized, which is a separate and non-negotiable point — the substitutes worth buying are iodized too.
The United States numbers differ from the global ones but point the same direction. The CDC reports that Americans take in more than 3,300 mg of sodium a day on average, against a federal recommendation of under 2,300 mg for teens and adults; a single teaspoon of table salt carries about 2,400 mg. The FDA puts average intake near 3,400 mg a day, notes that 90% of Americans exceed the recommendation, and adds a detail that matters later in this story: more than 70% of US sodium arrives in processed, packaged and prepared foods, not from salt added at the stove. MedlinePlus carries the same consumer line — most adults should stay under about 2.3 g of sodium (roughly a teaspoon of salt) — and flags who tends to be more salt-sensitive, including people with high blood pressure, diabetes or kidney problems.
What the trials show
The fullest summary to date is a systematic review and network meta-analysis published in BMC Medicine on 23 January 2026. It pooled 34 randomised controlled trials covering 37,063 adults in 15 countries, with a mean age of 62.3. Moderate-potassium, low-sodium substitutes — between 25% and 40% potassium chloride — probably reduce all-cause mortality, cardiovascular mortality, non-fatal cardiovascular events and systolic blood pressure compared with regular salt. In absolute terms the review reported 7 to 17 fewer deaths per 1,000 people, and systolic pressure 4.39 to 4.64 mmHg lower. The authors graded that body of evidence moderate-to-high certainty.
By far the largest contributor is the Salt Substitute and Stroke Study, run across 600 villages in northern China. Its prespecified analysis in people who had already had a stroke, published in JAMA Cardiology in April 2025, followed 15,249 such patients for a median of 61.2 months on a substitute of 75% sodium chloride and 25% potassium chloride. Systolic pressure ran 2.05 mmHg lower (95% CI −3.03 to −1.08). Recurrent stroke was lower (rate ratio 0.86, 95% CI 0.77–0.95), with a 30% relative reduction in haemorrhagic stroke, and deaths were lower too (0.88, 0.82–0.96), including a 21% relative drop in stroke deaths. Hyperkalaemia — the raised blood potassium that is the theoretical worry with these products — did not differ significantly between groups (1.01, 0.74–1.38).
A further sub-study in the Journal of Clinical Hypertension narrowed the lens again, following 4,211 participants from 120 villages in Shanxi province for an average of 4.66 years. There, the cardiovascular benefit was statistically significant among people already taking antihypertensive medication (rate ratio 0.81, 0.68–0.95) and not significant among those who were not (0.91, 0.62–1.32).
Where the evidence thins
The 2026 review is unusually candid about its own limits, and they are the most useful part of it. The mortality and cardiovascular benefit is “predominantly driven by one large Chinese trial” — SSaSS, with 20,995 participants. When the authors removed that trial from the analysis, the all-cause mortality result lost statistical significance. Among the non-Chinese studies, none contributed any mortality data at all. Their own conclusion: the evidence base “has very limited generalisability beyond Chinese populations with high discretionary salt use,” and large trials in other populations are needed.
Safety carries a second asterisk. The review found no increase in adverse events or withdrawals, and called the substitutes acceptable and comparable to regular salt — but only in people without kidney impairment, and it states directly that clinicians should rule out kidney disease and hyperkalaemia risk before recommending them. Potassium that the kidneys cannot clear efficiently is the specific hazard, which is why the products are a conversation to have with a clinician for anyone with reduced kidney function or on medicines that raise potassium.
A projection is not a result
Some of the newest material is modelling rather than measurement. In July 2026, The Lancet Regional Health – Western Pacific published a microsimulation for Chinese stroke survivors that used SSaSS and other inputs to estimate the lifetime consequences of fully adopting potassium-enriched salt across 24.1 million people. It projected 3.7% fewer recurrent strokes, 15.0% fewer stroke deaths, an extra 0.74 years of life expectancy, 10.79 million additional quality-adjusted life years and US$417.28 million in lower direct healthcare costs — a cost-saving intervention by the model’s reckoning.
Every one of those figures is an output of assumptions, not an observed outcome. That kind of study is genuinely useful for policy and budget arguments; it is not evidence that any individual will add three-quarters of a year of life. Read it as an illustration of what a population-level shift could plausibly produce, and nothing more.
The shaker is the small lever
For all the attention a substitute on the table gets, the FDA’s data put most of the problem elsewhere. More than 70% of sodium in the US food supply is added before the food reaches a kitchen, so a blended salt at home works on the smallest slice of the total. That is why the WHO’s sodium “best buys” are aimed at industry and institutions — reformulating products and setting sodium targets, front-of-pack labelling, lower-sodium options in hospitals, schools and workplaces — rather than at individual shoppers. It is the same structural point that runs through the ultra-processed food debate, where the largest recent synthesis also found that the category, not the condiment, is where most of the exposure sits.
None of that makes home cooking irrelevant. The FDA notes that people usually do not notice sodium reductions of about 10%, and that palates adjust as the reductions accumulate — the same gradual logic that makes sweetened drinks a sensible place to start, as our piece on signs you are drinking too much soda sets out.
What this is not
This is not medical advice, and it is not a recommendation to go and buy a particular product. Anyone with kidney disease, anyone taking potassium-sparing diuretics or blood-pressure medicines such as ACE inhibitors or ARBs, and anyone managing hypertension should talk to a healthcare professional before changing the salt they cook with — that is precisely the group the trials’ safety caveat points at, and it is a question for a clinician and a blood test, not a label.
What the evidence honestly supports is narrower than the packaging implies and stronger than most of what sits beside it on the shelf. Potassium-enriched salt is a real intervention with real trials, a plausible effect on stroke and blood pressure, one very large Chinese study carrying most of the mortality signal, and no mortality data at all from anywhere else. Read it as information about a claim, not as a prescription.