There’s a reason beauty fans flock to ingredients that promote cellular renewal: Young, spry cells reflect more light and generally perform better. So imagine a buildup of zombie cells living rent-free in your skin—your complexion might appear dull, dry, and creepy. 

“Since senescent cells have reduced cellular renewal, it can lead to a reduction in collagen and elastin as well as a weaker skin barrier,” explains Garshick. “Together these changes can lead to dryness, fine lines, wrinkles, and dullness of the skin.” 

What’s more, “Senescent cells secrete pro-aging factors that can drive healthy neighboring cells to age faster and become senescent as well,” says Russak. Just like the living dead, these zombies corrupt the healthy cells around them, turning them into zombie cells, too. Spooky, no? 

And as more and more cells become senescent, the skin ages even faster. “The accumulation of senescent cells in the skin leads to reduced production of collagen, elastin, and hyaluronic acid, decreased epidermal thickness, compromised barrier function, and decreased elasticity and strength,” Russak adds.