Potassium Aspartate

Potassium aspartate is a potassium salt of the amino acid aspartic acid, used primarily as a humectant/skin-conditioning electrolyte in low concentrations, and it is generally well tolerated in patch-testing and routine cosmetic use. It is not an acid exfoliant at typical formulation pH and lacks the barrier-disruptive activity seen with stronger actives, so irritation risk is low. In severely compromised or highly reactive eczema skin, any ionic salt can occasionally sting, so I score it as very gentle rather than inert. Safety Notes: Potassium aspartate is most commonly used as an amino-acid-derived humectant/skin-conditioning electrolyte within amino-acid complexes or NMF-style blends, where it can appear at trace-to-low levels (~0.001–0.05%) in leave-on moisturizers, toners, and serums (and similarly in rinse-off cleansers). Higher-strength consumer products that emphasize “amino acid/electrolyte” hydration or use concentrated amino-acid complexes can reach ~0.5–2.0% potassium aspartate in leave-on formats, with practical upper limits driven by ionic strength, tack/skin feel, and pH/compatibility rather than specific regulatory caps.