We’ll start with the big one: Your skin barrier function can weaken from cold, arid air, which contributes to increased transepidermal water loss (or when water literally evaporates from your skin). That’s exactly why you may face increased dryness at the moment—your skin is losing a ton of water to the outside.
To keep that water locked in, experts recommend layering on emollient-rich creams (star ingredients include shea butter, ceramides, and certain oils) to seal the outer layer of skin and keep moisture inside. But according to research, you should ingest these skin barrier-supporting ingredients, too—namely, ceramides.*