Comedogenic

Comedogenicity refers to the tendency of a substance to promote the formation of comedones — clogged follicles that appear as blackheads (open) or whiteheads (closed). Comedogenicity ratings (0–5 scale) were originally derived from rabbit ear occlusion models and have limited direct applicability to human use at real-world concentrations. An ingredient rated comedogenic in isolation may not cause breakouts in a dilute rinse-off formula. Acne-prone skin types are most susceptible, but individual response is highly variable.

• Non-comedogenic A label claim indicating a product is formulated not to clog pores.
• Patch test Applying a small amount of a product to a discreet skin area for 24–48 hours to check for adverse reactions before full use.