Ammonium Chloride

Ammonium chloride is primarily a pH adjuster/viscosity modifier and is typically used at low concentrations, but as an inorganic salt it can be stinging and irritating on compromised skin due to osmotic and pH-related effects. Patch testing and clinical experience show it can provoke irritation (more than true “gentle” excipients), particularly on eczematous, barrier-impaired, or freshly shaved/post-procedure skin. Given the sensitive-skin risk profile and the need for patch testing in reactive individuals, it warrants a moderate irritancy score. Safety Notes: In consumer skincare, ammonium chloride is most often used at very low levels (~0.05–1%) as a pH adjuster/buffer or viscosity modifier in cleansers, shampoos/body washes, and some creams/lotions, where it functions primarily as an inorganic salt rather than a headline active. The highest OTC consumer-available levels are observed in specialized rinse-off products (notably bath/foot soaks and certain cleansing systems where it acts as a strong electrolyte/processing aid), reaching roughly 10–15%; such high levels are uncommon in leave-on products due to irritation potential and sensory constraints.