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.


 


Measurement Of Skin-Type Versus Subjective Perception
As with sebumetry [9] sebum levels can be reliably assessed, but we as users have a general problem with the subjective assessment of our skin types. Additionally, sebum levels are not constant.

Generally, they are higher in males than in females. They change with age, with the season (highest in summer), can be influenced by nutrition and vary even within one area – the face.
TU zones
In the past, there has been a considerable amount of documentation [10-13]. It has been tried to correlate different biophysical parameters of skin with facial areas and subjective skin types [14]. Youn et al. investigated a Korean collective and realized: that the forehead and nose are more oily than the chin and cheek, regardless of skin type.

Therefore they also define a U-zone, additional to the well established T-zone [15].

Figure 2: Investigations of Youn [15] clearly show that T-zone: forehead and nose are more oily than U-zone: cheek and chin. That applies to all subjectively assessed skin types.

Even though this is not sufficient to describe what is found in practical experience, skin types are broadened for combination skin [16]. Combination skin also is an established skin type, which unfortunately does not help the consumer to choose the right product.


Baumann Skin-Type Classification And Sensitive Skin
For many skin-type classifications, sebum content alone is not regarded as sufficient. Therefore other methods have been established. One of the more descriptive methods is the classification developed by dermatology professor Dr. Leslie Baumann. 


Baumann types
She differentiates between skin oiliness, skin discolouration (pigmented moles), wrinkle-prone skin and sensitivity. In total, this accounts for 16 skin types (figure 3). Additionally, she devotes a lot of consideration to sensitive skin. Sensitive skin cannot be detected via established biophysical methods [18].

Even though there are indications that TEWL (transepidermal water loss) is enhanced or increased sensitivity towards certain trigger molecules (i.e. Capsaicin) exist [19]. Nevertheless, this skin type is difficult to assess.

Dr Baumann, therefore, dedicates a lot of attention to the questionnaire on subjective perception [20] and eventually classifies skin diseases like acne or rosacea as sensitive skin [21]. This sounds logical, as according to her definition, the opposite of sensitivity is resistance.

Skin-Type And Skin Moisturization
Looking at the skin-type classifications it is obvious that the biophysical parameter of skin moisturization is not assessed. Although different zones of the facial skin have different moisturization levels, moisturization and sebum levels do not correlate [14]. On the contrary, there is growing evidence that skin moisturization – this is what most skincare products do – might not be beneficial.


Skin-Type And Reality
In contrast to ethnic skin types [22] and Fitzpatrick skin types, cosmetic skin types are not fixated. They can vary according to intrinsic or extrinsic factors. Additionally, the role which sebum plays on skin has been underestimated for a long time. Just now there are indications emerging on the many effects of sebum.

It is orchestrating how the epidermal lipids (also known as barrier lipids) are formed [23]. Furthermore, sebum also acts in a positive way on the barrier function of the skin in an immunological sense [24].

Sebum interactions
Figure 4: Multiple interactions of sebum with skin barrier functions [24]. Sebum not only forms a lipid layer on the skin, it’s degradation products also react with immunocompetent cells and form a favourable milieu for a healthy skin microbiome.

If the skin is colonized with Demodex Folliculorum (a mite) more sebum is secreted and skin pH is slightly elevated [25]. These putative changes can already be sufficient to influence the bacterial composition of the skin (microbiome). How and how strongly, that we do not know today. But the intentional supply of moisture and oil can make changes in the microbiome composition [26, 27]. There are changes when skin moisture is elevated on a usually oily area like the forehead or oiliness is elevated on an originally dry area like the cheek [26]. But also elevating moisturization levels on the cheek lead to changes [27]. Taken together these can be indications of how acne can be triggered.

formation pathway
Figure 5: Possible formation pathway of sensitive skin. Sensitive skin could originate either from oily or dry skin.

As acne is a multifactorial skin disorder, that often is correlated with increased sebum secretion. But investigation results in this respect are conflicting. Acne itself is an infectious disease that is triggered only by some members of the big family of Propionibacterium Acnes [28, 29].

Ways To Leave The Skin-Type Chaos
It is said that Helena Rubinstein "invented" the skin types at the beginning of 1900. And hence it looks like the cosmetic skin types are rather a marketing tool [30]. Therefore it is not surprising that subjective skin types and biophysical measurements do not correlate. Sensitive skin ideally can be assessed using a questionnaire. Sensitive skin can also be a result of wrong treatment, especially cleansing [31].

When choosing our skincare products we should pay attention, especially with acne or rosacea skin, not to use products with strong moisturizing action. Also, internet-based guidebooks can be misleading or wrong. Using skin cleansing products we should be careful not to choose such with strong sebum reducing action. Because sebum and all skin surface lipids are an integral component of the skin barrier[(32]. A good skincare product respects and supports it. Producers like Johnson & Johnson already know this and inform on their internet sites [33].

I do not think that we will still talk about cosmetic skin types within the course of the next ten years. The trend is moving towards the individualization of skincare [34]. And DNA tests are discussed to optimize this [35].

What’s Your Skin Type?

Medically Reviewed by Poonam Sachdev, MD on October 13, 2021 Written by Annie Stuart
Normal Skin Type
Combination Skin Type
Dry Skin Type
Oily Skin Type
You’ve heard the buzz about normal, oily, dry, combination, or sensitive skin types. But which one do you have?

It can change over time. For example, younger people are more likely than older folks to have a normal skin type.

What’s the difference? Your type depends on things such as:

How much water is in your skin, which affects its comfort and elasticity
How oily it is, which affects its softness
How sensitive it is
Normal Skin Type
Not too dry and not too oily, normal skin has:

No or few imperfections
No severe sensitivity
Barely visible pores
A radiant complexion 
Combination Skin Type
Your skin can be dry or normal in some areas and oily in others, such as the T-zone (nose, forehead, and chin). Many people have this type. It may need slightly different care in different areas.

Combination skin can have:

Pores that look larger than normal because they’re more open
Blackheads
Shiny skin

Dry Skin Type
You may have:

Almost invisible pores
Dull, rough complexion
Red patches
Less elastic skin
More visible lines
Your skin can crack, peel, or become itchy, irritated, or inflamed. If it’s very dry, it can become rough and scaly, especially on the backs of your hands, arms, and legs.

Dry skin may be caused or made worse by:

Your genes
Aging or hormonal changes
Weather such as wind, sun, or cold
Ultraviolet (UV) radiation from tanning beds
Indoor heating
Long, hot baths and showers
Ingredients in soaps, cosmetics, or cleansers
Medications


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Use these tips to help your dry skin:

Take shorter showers and baths, no more than once daily.
Use mild, gentle soaps or cleansers. Avoid deodorant soaps.
Don't scrub while bathing or drying.
Smooth on a rich moisturizer right after bathing. Ointments and creams may work better than lotions for dry skin but are often messier. Reapply as needed throughout the day.
Use a humidifier, and don't let indoor temperatures get too hot.
Wear gloves when using cleaning agents, solvents, or household detergents.
Oily Skin Type
You may have:

Enlarged pores
Dull or shiny, thick complexion
Blackheads, pimples, or other blemishes
RELATED:
Home Treatments for Psoriasis

Oiliness can change depending upon the time of year or the weather. Things that can cause or worsen it include:

Puberty or other hormonal imbalances
Stress
Heat or too much humidity
To take care of oily skin:

Wash it no more than twice a day and after you sweat a lot.
Use a gentle cleanser and don't scrub.
Don't pick, pop, or squeeze pimples. They'll take longer to heal.
Look for the word "noncomedogenic" on skin care products and cosmetics. This means it won’t clog pores.
Sensitive Skin Type
It can show up as:

Redness
 Itching 
Burning
Dryness
If your skin is sensitive, try to find out what your triggers are so you can avoid them. There are many possible reasons, but often it's in response to particular skin care products.


Why Does It Matter?
 

Skin Hydration for Different Skin Types
Before you buy skin care products, it’s a good idea to know your skin type and other things that contribute to the look and feel of your skin, like: 

  Your skin complexion. Does your skin burn easily, rarely, or never?
 Your skin care goals. Are you trying to prevent premature aging? Do you have a skin problem, such as acne or rosacea, or other concerns, such as dark circles under your eyes or fine lines?
 Your personal habits. Do you smoke? Do you spend a lot of time in the sun? Do you take a daily vitamin? Do you eat a well-balanced diet? All these factors may affect how you should care for your skin.
This information can help you sort through skin care products for those that suit you. If you need help, ask a dermatologist or an aesthetician at a skin care counter for recommendations.

The 6 Basics of Skin Care
No matter what type of skin you have, these tips will keep it looking its best.

Use a broad-spectrum sunscreen that blocks both UVA and UVB rays.
Avoid direct sunlight, and wear a hat and sunglasses.
Don't smoke.
Stay hydrated.
Wash your skin gently but thoroughly every day and never wear makeup to bed.
Moisturize.