Correlation Between External and Internal Skin Aging Markers by Skin Depth

The skin is a complex, multilayered organ with diverse structures. Skin aging is a gradual process that begins internally, initially invisible to the eye, and eventually manifests as visible signs such as wrinkles and sagging.

To investigate the effects of characteristic changes in different skin layers on visible signs of aging, such as wrinkles and sagging.

A total of 65 Korean women aged 20-65 years participated in this study. Skin characteristics were categorized into visible external and invisible internal markers. External markers included wrinkles and sagging, whereas internal markers included hydration, elasticity, density, thickness, and dermal-subcutaneous interface length. Internal markers were measured in greater detail at various skin depths. Spearman's correlation was used to analyze relationships between all skin parameters, including age.

Visible signs of aging such as wrinkles and sagging increased with age. The elasticity indicators in each skin layer tended to decrease. No correlation was observed between moisture levels and age. The results of the correlation analysis between external and internal markers varied according to skin layer. Negative correlations were observed between skin sagging and epidermal moisture content in the epidermis and between wrinkles and elasticity indicators (Ue and Ur) in the deeper dermis layer.

External markers are most strongly correlated with chronological age. However, visible aging is significantly influenced by changes in internal markers across different skin layers. Sagging is affected by moisture content within the epidermal layer, and wrinkles are affected by elasticity within the dermal layer.