Potassium-containing low-sodium salt substitutes consistently reduced systolic blood pressure by 4.6-8.9 mmHg and diastolic pressure by 1.4-4.0 mmHg across eleven systematic reviews. Later analyses also suggested reduced all-cause mortality (12-13% lower risk) and cardiovascular deaths (13-28% reduction), though these clinical outcomes were heavily influenced by a single large Chinese trial. Serum potassium levels changed minimally, and serious adverse events showed no clear excess risk in study populations that largely excluded high-risk individuals. This umbrella review represents an important synthesis for cardiovascular prevention, given that even modest blood pressure reductions can translate to meaningful population-level health benefits. The consistency of blood pressure effects across multiple reviews strengthens confidence in these findings, though methodological quality varied considerably among the included studies. Critical limitations include geographic concentration in Eastern Asia, unclear salt formulation reporting, and insufficient safety data for people with kidney disease or other conditions affecting potassium handling. As this is a preprint awaiting peer review, these conclusions require validation. The findings suggest promise for a simple dietary intervention, but broader geographic trials and clearer safety profiles are essential before widespread implementation.