Potassium Citrate

Potassium citrate is primarily a pH adjuster/buffering agent used at low concentrations, and it is generally well-tolerated in leave-on and rinse-off products when formulations are kept near skin-physiologic pH. Irritation is uncommon but can occur in highly compromised barriers (e.g., active eczema) if it contributes to stinging in an already disrupted skin environment or if overall formula pH/ionic strength is poorly balanced. Given its low intrinsic reactivity but nonzero stinging potential in sensitive populations, it fits best as very gentle rather than inert. Safety Notes: Potassium citrate is most commonly used as a buffering/pH-adjusting salt in leave-on and rinse-off products, where it often appears at trace-to-low levels (~0.01–0.3%) as part of a citrate buffer system alongside citric acid and/or sodium citrate. In higher-alkalinity or strongly buffered consumer products (e.g., some cleansers, shaving products, depilatories, and select high-buffer or salt-rich specialty formulations), total use can reach the low single digits, with observed upper-end OTC formulations around ~3–5% when significant buffering/ionic strength is needed. It is not subject to a specific EU/FDA max concentration limit as a cosmetic ingredient, so practical limits are typically driven by pH targets, ionic strength, sensorial effects, and compatibility/stability rather than regulation.