15.3% of patients experienced mild to moderate local side effects (dryness, peeling, erythema, burning), but no one discontinued due to side effects, indicating the combination is irritant but tolerable
Zebrafish embryo developmental toxicity test showed teratogenicity index of HPR microcapsule was 1.9, lower than positive control SymRenew™ HPR (3.1), but this is animal high-dose exposure via water bath (systemic-like), relevance to topical cosmetic use needs caution.
Human patch test and hemolysis assay demonstrated that the nanoemulsion significantly reduced HPR irritation, indicating no irritation risk for HPR in this delivery system.