Beauty Science
Deep Dive
The Rating System
Comedogenic ratings originated from rabbit ear testing conducted in the 1970s-80s, where ingredients were applied to rabbit ears and monitored for comedone formation. Ratings range from 0 (non-comedogenic) to 5 (highly comedogenic). Common examples: mineral oil (0-1), coconut oil (4), isopropyl myristate (5).
Limitations
The comedogenic rating system has significant limitations: it was developed using animal models that may not reflect human skin behavior, it tests individual ingredients rather than complete formulations, it doesn’t account for concentration or formulation context, and individual skin chemistry dramatically affects comedone formation.
Modern Application
Despite its limitations, the comedogenic scale remains widely referenced by consumers and brands. Modern non-comedogenic testing uses human subjects with real-world application patterns, providing more relevant data than the original rabbit ear studies.
OSF Perspective
OSF advises using comedogenic ratings as a general guide rather than absolute rule — individual skin chemistry, product formulation, and usage patterns all influence whether a product causes breakouts for any specific person.
Related Terms
BHA | AHA | Formulation | Skin Barrier | Patch Testing
Notable Brands
CeraVe (non-comedogenic range), La Roche-Posay (Effaclar), Paula's Choice, Clinique