Everyone who loves beauty wants to have good skin. However, the weather will give us new challenges every time. The two devils, dry and sultry, will become pairs in any time. So what caused our skin to dry? Ausmetics tells you with 21 years of research experience.
Epidermal cell lipid metabolism
There was a significant change in the ultrastructure of the stratum corneum between normal and dry skin, and there were significant differences in the number and arrangement of lipids. Preliminary analysis of the lipid components of normal and dry skin stratum corneum showed a significant decrease in ceramide levels in severely dry skin compared to normal skin. However, the relative levels between different ceramide species remain unchanged, as shown in Table 1-1.
Changes in the ratio of the three major lipid components (fatty acids, sterols, ceramides) were observed in the dry skin, causing phase separation of the stratum corneum surface lipids. Excess fatty acid levels may further exacerbate structural defects in intercellular lipids.
Epidermal cell protein expression abnormality
- Increased expression of immature keratinized envelope. The immature keratinized envelope rises more than healthy skin and becomes weak and hydrophobic. The ability to covalently bind to ceramide is reduced, affecting the tightness and integrity of the skin barrier structure.
- Increased expression of immature keratinocytes. Affect the stratum corneum barrier function.
- Reduced desmozyme activity. The undegradable desmosomes remain in the exfoliated stratum corneum, causing the aging keratinocytes to not completely detach. This thickens the stratum corneum and makes the skin surface uneven. Excessively thick stratum corneum will accelerate the loss of moisture in the skin, making the water content of the epidermis lower, which will aggravate the symptoms of dry skin.
Epidermal cell immune response and drying
After the epidermal decline is acute or chronic, the skin’s spontaneous repair mechanism will accelerate the production of keratinocytes. Epidermal cell replacement time is shortened and mediates the production and release of cytokines. This causes hyperkeratosis of the skin and mild inflammation, which is also a typical feature of dry skin symptoms.
How do we choose moisturizing cosmetics?
Dry skin means that the skin barrier is disordered, lipid loss, protein reduction, and local inflammatory factors are released. Dry skin caused by barrier damage is not the same as the drying mechanism caused by the reduction of sebum secretion. The effect of simply supplementing lipids is often not expected.
- Moisturizing cosmetics developed for barrier damage not only need to supplement the stratum corneum moisturizing factors, such as ceramides, natural moisturizing factors.
- Take into account the effects of anti-oxidation, anti-inflammatory and anti-cell division, thereby reducing keratinocyte differentiation.
- Barrier skin dryness is often accompanied by skin itching, should be considered to add antipruritic actives.