Role of Ceramides

Ceramides are fat molecules in the skin that form a barrier to help protect the body and keep skin moisturized. 

Where Ceramides Are Located

The top layer of the skin is called the epidermis, and the top layer of the epidermis is called the stratum corneum (SC). Even though the SC is very thin—10-30 millimeters or one-tenth the thickness of a piece of paper—it is the main barrier of the skin.

It keeps chemicals that come in contact with the skin from absorbing into the body, and it keeps water inside the skin from leaching out.

The SC contains three types of lipids: ceramides, cholesterol, and free fatty acids. These lipids have different chemical compositions and different functions throughout the body. There are nine different types of ceramides in the SC, which are conveniently named ceramide 1 through ceramide 9, and they account for 40 percent to 50 percent of the lipids in this outermost layer.

How Ceramides Play a Role in Certain Skin Diseases

Scientists have learned that people who have eczema have significantly fewer ceramides in their SC. On the other hand, people who have psoriasis (another itchy, flaky rash that's sometimes confused with eczema) have the same number of ceramides as people who have normal skin. However, people who have psoriasis have less of ceramide 1, 3, 4, and a subset of 5 and 6, and they have more of ceramide 2 and another subset of 5.

Replacing Ceramides May Improve Eczema

Recent studies have shown that lipids can be replaced with topical preparations. Interestingly, all three types of lipids have to be replaced at a certain ratio in order to restore the barrier function of the skin. If the incorrect balance of lipids is applied, it actually takes longer for the skin to heal.

The healing effect of ceramides on eczema has been studied, but there are no studies yet that have looked at the possible healing effect of ceramides on psoriasis.

The Relationship Between Ceramides and Aging

Once you hit your early 30s, the level of ceramides in your skin begins to decrease. As a result, your skin barrier weakens, and this can lead to certain skin symptoms, such as irritation, dryness, and redness. Some skincare products that contain ceramides may help improve these symptoms, as well as reduce signs of aging in the skin, like wrinkles. 

Moisturizers with Ceramides Are Not All the Same

There are several moisturizers that claim to have ceramides as ingredients, but these are just regular moisturizers unless they can show that:

• The moisturizer also contains cholesterol and free fatty acids
• The ratio of these three ingredients is correct

Avoid Oral Supplements With Ceramides

There isn't enough research at the moment to support the claim that oral supplements with ceramides can help treat skin conditions, so it's best to stick with topical moisturizers.