If you apply beauty products to your skin on a regular basis you may have heard the word ceramide pop up once or twice. This has become a vital ingredient in skin care creams that helps moisturize, soften and generally revitalize your skin. But ceramide is actually a molecule that already permanently resides in your skin cells, performing all of the jobs that these beauty products try to boost.

A ceramide is a lipid molecule, which are naturally occurring molecules such as sterols and fats. Lipid’s have one of three functions -- they make up part of the structure of a cell’s membrane, storing energy or signaling actions in cells. Ceramide is a structural and signaling molecule. It is made up of a fatty acid called sphingosine and is located within the membrane of cells, in great concentrations. These cells can be found on the surface layer of your skin. The ceramide lipids limit the loss of water from your skin and acts as a barrier against harmful substances penetrating your skin.

Ceramide is produced in one of three ways. One such way is that enzymes make ceramide out of many similar molecules. Another method is for sphingolipids to be broken down by enzymes to create ceramide. Lastly, sphingomyelin from the cell membrane goes through hydrolysis, activated by an enzyme called sphingomyelinase. Hydrolysis means that a molecule is broken down with water -- this process generates ceramide.

Ceramide is a proapoptotic molecule, meaning it is apoptosis inducing. Apoptosis is a form of programmed cell death, which is the death of a cell caused by a program within that cell. This process is a fundamental function in the development of tissue. Ceramide also induces the multiplication, growth and migration of cells.

Ceramides have become a common ingredient in skin care products. Age wears down the effectiveness of ceramides, meaning dryer and rougher skin, as well as wrinkles. Ceramide skin products contain natural or synthetic ceramides that aim to increase hydration in the skin and strengthen its moisture barrier. This is claimed to leave skin smooth and youthful.