# Biological Effects of a Fine Fiber Film Treated With a Lotion to Improve Dry Skin

## TL;DR

A lotion combined with a fine fiber film improves dry skin faster than lotion alone by affecting skin proteins related to hydration and barrier function.

## Contribution

The study reveals the biological mechanism by which a fine fiber film enhances lotion efficacy in treating dry skin.

## Key findings

- Skin dryness scores and conductance improved more with lotion and fine fiber film than lotion alone.
- Suprabasin protein levels increased in the granular layer and stratum corneum after treatment.
- FF film with lotion reduced annexin A2 and increased retroviral-like aspartic protease 1 in the skin.

## Abstract

Dry skin is a universal skin concern that is often accompanied by itching, but moisturizers have not completely solved this issue. We found that the combination of a moisturizer (lotion) and an ultra‐thin film of fine fiber (FF) that we developed improved dry skin early, but the biological mechanism within the skin remained unclear.

Eight (Study 1) and seven (Study 2) subjects used a lotion with and without the FF film on their lower legs. In addition to measurement of visual skin dryness scores and conductance, proteomic analysis of stratum corneum (SC) samples at baseline and 14 days after treatment in Study 1 and immunohistochemical staining of skin biopsy samples 3 or 5 days after treatment in Study 2 were performed.

Skin dryness scores and conductance improved more when the lotion was used with the FF film than with the lotion alone. The protein expression level of suprabasin, which is related to epidermal differentiation and barrier function, increased within a few days near the granular layer, as well as in the SC after 14 days. Proteomic analysis using SC samples showed that the FF film treatment with lotion decreased annexin A2, a dry skin marker, whereas it increased retroviral‐like aspartic protease 1, which is related to skin water content, more than lotion alone.

The present findings suggest that lotion with the FF film initiates restoration of epidermal homeostasis, leading to early improvement of dry skin.