Potassium Chloride

Potassium chloride is an inorganic electrolyte used in cosmetics mainly as a viscosity/tonicity adjuster, typically at low concentrations where it is generally well tolerated and not a common cause of true allergic contact dermatitis. However, like other salts it can sting and increase dryness on compromised barriers (eczema, post-procedure skin) due to osmotic effects, so I do not score it as fully inert for highly reactive patients. Safety Notes: In consumer skincare, potassium chloride is most often used at very low levels (trace to ~0.1%) as an electrolyte/tonicity adjuster or to support viscosity in surfactant systems, so the lowest observed commercial use is around 0.001% where it functions as a minor ionic strength modifier. Higher levels are seen primarily in rinse-off cleansers, bath/shower products, and some salt/electrolyte-focused body products where it can be used as part of the salt system to thicken or adjust osmolarity, reaching about 1–5% in OTC products; leave-on products rarely exceed ~0.5–1% due to potential sting/irritation and tack/salt feel at higher ionic strength.

Suitability