Steapyrium Chloride

Steapyrium Chloride appears to be a quaternary ammonium (“quat”) cationic surfactant/conditioning agent, a class known to cause irritant contact dermatitis and stinging—especially on compromised skin—at typical leave-on or cleansing-use levels. Clinical patch-testing and real‑world use of similar quats show notable irritation potential due to their membrane-disruptive, surfactant nature, with higher risk when combined with other actives or barrier impairment (e.g., eczema). Given the uncertainty around this specific INCI but the well-established irritancy profile of the class, a cautious notable score is warranted for patient safety. Safety Notes: No credible evidence supports “Steapyrium Chloride” as an established INCI cosmetic ingredient, and it does not appear in standard cosmetic ingredient inventories used on consumer product labels (e.g., EU CosIng/INCI listings) or in recognizable commercial skincare formulations. Because it is not observed in real-world OTC consumer skincare products under this name, the practical market concentration range is effectively 0% across both leave-on and rinse-off categories; if encountered, it is likely a misspelling or non-INCI naming of a different quaternary ammonium compound.