Pores are small openings in the skin that release sweat and oil, but they can become clogged—especially in people with oily skin. According to dermatologist Dr. Geeta Yadav, this usually happens when excess oil mixes with dead skin cells that haven’t shed properly. Makeup, dirt, and pore-clogging (comedogenic) ingredients can worsen the issue.
These ingredients aren’t the only cause of acne, but they increase the risk, says dermatologist Dr. Rachel Nazarian. For those with oily skin or acne-causing bacteria, using comedogenic products can lead to frequent breakouts.