Comedogenicity refers to the tendency of an ingredient to clog pores. Unfortunately, regulations on cosmetic labeling are relatively loose and companies can label their products "non-comedogenic" whether it is true or not. Acne sufferers in particular tend to get caught up in marketing traps by purchasing products with false labels like "oil-free" and "deep pore cleansing" and end up making their condition worse. Just like choosing food at the grocery store, the only way to really know what a product is about is by reading the ingredients list. Next time you go to buy your skincare and cosmetic products, take this list with you and make sure you are not buying any pore-clogging products.