Ceramides are lipid molecules that make up about a third of your skin's barrier (along with cholesterol and fatty acids in roughly equal amounts). They keep your skin's outer layer tightly sealed and hydrated by staying in a solid, crystalline state at body temperature. Most skin conditions with compromised barriers show lower total ceramide levels, and adding ceramides to products may help restore function.

This was a literature review and analysis of existing research on ceramide structure and function in skin, not a new experiment. The authors examined how ceramides work chemically and what happens to them in various skin conditions.

Funding not disclosed in abstract