Cutibacterium acnes, a crunchy Cheeto-shaped bug that lives on human skin, loves the oily pocket around hair follicles. No face is quite as greasy as that of adolescents, flooded with hormones that grow hair, deepen voices, and ramp up production of sebum, a secretion that makes the skin a moist and protective barrier.
Too little sebum means dry, flaky skin, like patches of eczema. Too much sebum means acne, the skin disease caused by C. acnes. Bumps and zits and blackheads sprout on most teenagers and, increasingly, on the faces of young adults, even into their 20s and 30s. And, in people with extra-oily skin, the body’s natural defenses can’t seem to get rid of the bacteria.