**Pores.** We all have tiny openings in our skin that release sweat and oil, but for some people, these pores can be more problematic than for others. In other words, some of us experience clogged pores more often. Pores become clogged when oil either doesn’t flow through them or can’t pass through properly, explains board-certified dermatologist Dr. Geeta Yadav. “This is typically caused by an overproduction of oil, which then gets trapped with dead skin cells that haven’t properly shed from the pore lining. Makeup, dirt, and/or comedogenic ingredients can also block pores and prevent oil from passing through,” she says.
**Comedogenicity** is essentially a term that refers to the tendency to clog pores. While these types of ingredients aren’t the only cause of acne and breakouts (there are several contributing factors), they certainly don’t help. “Pore-clogging ingredients increase the likelihood of breakouts,” says board-certified dermatologist Dr. Rachel Nazarian. “For someone with naturally oily skin or acne-causing bacteria, using these ingredients is like pouring gasoline on a fire. It’s a dangerous combination that can worsen acne and lead to persistent breakouts.”
So what exactly makes an ingredient comedogenic? The short answer: we don’t fully know. “Comedogenicity isn’t completely understood,” says Yadav. “In some cases, ingredients might interact poorly with sebum, making it thicker, while other ingredients are simply too dense for oil to pass through.” At this point, pore-clogging ingredients are usually occlusive, adds board-certified dermatologist Dr. Melanie Palm. They sit on the skin’s surface, forming a seal that ends up trapping oil—especially for those with already oily skin. Palm also notes that some pore-clogging ingredients add more oil to the skin, causing cells to stick together more tightly instead of shedding normally from the pore lining.
