"Without getting too complicated, think of exfoliating as actively removing the topmost layer of dead skin," says board-certified dermatologist Flora Kim, M.D., FAAD. "While cell turnover relates to the life or maturation of a skin cell from birth to death, the cell moves up and up until it is peeled off." Essentially: Exfoliating sheds the dead skin cells, but the turnover replaces them with younger and more zippy ones.
That's why scrubs are more likely to glow instantly, as they instantly dissolve the surface layer of excess dead skin. While ingredients that promote cell turnover (such as retinoids) optimize the life cycle of the skin cells and push fresh baby cells upwards – when this happens, these old cells peel off, but it takes a little longer. And because cells respond more slowly to wound healing as they age, accelerating cell turnover can give your skin the boost it needs to reduce hyperpigmentation and fine lines, and stimulate collagen production.
You should know, however, that exfoliation and cell turnover are not mutually exclusive: many exfoliants (like AHAs and BHAs) promote cell turnover and remove dead skin cells at the same time. and consequently cell turnover leads to dead skin as younger cells are pushed to the surface. Some peels, while dissolving dead skin cells on top, do not exactly promote cell turnover for living cells below – so the nuance is important to note.
Take enzymes, for example: "Enzymes are great for sensitive skin because they break down the proteins found in dead skin cells but don't cause cell death or turnover like acids," said Rory Melynda Barnes, MD, certified surgeon and clinical director , told us about enzymes against acids.
In other words, cell turnover can exfoliate, but exfoliating doesn't always mean you're promoting new skin cells to the top.