COSMETIC SKIN-TYPES – A MYTH OR CHAOS?

COSMETIC SKIN-TYPES – A MYTH OR CHAOS?
Cosmetic Skin-Types
We have to ask ourselves; are cosmetic skin types a combination of myths or chaos?  New insights lead to better understanding.

skin types titleSkincare products usually are marketed according to our skin types. In all the regular retail markets, where we usually obtain cosmetic products, they are typically grouped into three categories: dry, normal and oily [1, 2]. But the self-assessment of us as consumers of what to purchase is often flawed. Additionally, there is confusion by terms such as “dry” and “moisture deficient skin” (dehydrated) to widen the aspects of dry skin [3].

Eventually, we are incorrectly buying products for sensitive or combination skin. Here I want to take a closer look at the myth of skin types, which new insights are published and what this all can mean for skincare.

Skin-Type And The Oiliness Of The Skin
If we talk about skin types, we usually are referring to the cosmetic skin types [4] in contrast to professionally diagnosed skin types. For the purposes of this article, I will not be referring to skin types like “lipid dry“ and “permanent diffused redness“, as this is a topic for another time.

There are other skin types, which must be to be differentiated. The most important one is the Fitzpatrick (or phototype) skin type, which is used to classify the skin’s sensitivity (burn time) toward UV (solar) radiation [5].

Cosmetic skin types are dry, normal and oily, and are classified based on the sebum content on the skin. In dermatology, this is referred to as casual sebum level. Sebum is generated in the sebocytes which are located near the hair shaft in the pilosebaceous unit. From there sebum flows to the skin and spreads on the surface.

Composition of sebumFigure 1: Composition of sebum [6] shows, that the main ingredients are triglycerides and wax esters. All numbers are average, sebum composition underlies substantial individual variations.

The lipids on the skin surface are by all means not only sebum. Also epidermal lipids, the barrier lipids are found there.

They are composed of ceramides, long-chain free fatty acids and cholesterol [7]. Skin surface lipids therefore are a mixture of sebum and epidermal lipids [8].

How they interact with each other I cover later in this text.