Potassium Phosphate
Also known as Monopotassium Phosphate, Potassium Dihydrogen Phosphate, MKP, KH2PO4
“CIR Expert Panel says: safe as used in cosmetics.”
The CIR Expert Panel assessed Phosphoric Acid and its salts (31 ingredients, including Potassium Phosphate) and concluded they are safe in present cosmetic practices when formulated to be non-irritating. Potassium Phosphate (monobasic, KH2PO4, CAS 7778-77-0) functions primarily as a pH buffering agent and is distinct from the dibasic (K2HPO4) and tribasic (K3PO4) potassium phosphate variants, all of which are assessed in the same group report. The evidence base is limited to this group CIR assessment; independent ingredient-specific toxicology studies in cosmetic contexts are sparse.
Effective pH buffer in cosmetic formulations
Stabilizes emulsion systems
Mineral salt with established safety record in food and pharmaceutical applications
- · Must be formulated to be non-irritating; concentrated phosphate solutions can cause irritation at high pH
CIR Quick Reference Table (September 2022) — POTASSIUM PHOSPHATE row: Finding=SQ, Citation=IJT 40(S1):34-85;2021
“Potassium Phosphate | SQ | The CIR Expert Panel concluded that the following 31 ingredients are safe in the present practices of use and concentration in cosmetics as described in this safety assessment, when formulated to be non-irritating...Potassium Phosphate... | IJT 40(S1):34-85;2021”— QuickReferenceTable_AllConclusionTypes.pdf, p. 453