# Orally Administered Edible Snail Extract Powder Enhances Skin Hydration via Hyaluronic Acid Synthesis and Barrier Gene Modulation in SKH‐1 Hairless Mice

## TL;DR

Orally administered snail extract powder improves skin hydration and strengthens the skin barrier in mice by boosting hyaluronic acid and related genes.

## Contribution

Demonstrates for the first time that oral snail extract powder enhances skin hydration and barrier function in hairless mice.

## Key findings

- Oral SEP increased skin hydration and reduced transepidermal water loss in mice.
- SEP upregulated genes like Has1–3 and Flg while downregulating Hyal1 and Acer1.
- Higher hyaluronic acid levels and protein expression confirmed the mechanism of action.

## Abstract

SKH‐1 hairless mice were used as the in vivo model in this study to evaluate the efficacy of oral snail extract powder (SEP) on skin hydration and barrier enhancement. The skin serves as a primary barrier against external stimuli and plays a critical role in maintaining water homeostasis. Optimal skin hydration is essential for preserving barrier integrity and preventing dermatological conditions such as xerosis and atopic dermatitis. Although edible snail has demonstrated moisturizing effects when applied topically, its efficacy following oral administration has not been sufficiently characterized. In this study, we evaluated the moisturizing efficacy and safety of orally administered edible snail extract powder in SKH‐1 hairless mice. Animals were divided into a control group and three treatment groups receiving 20, 40, or 80 mg/kg B.W. of SEP daily for 13 weeks. Skin hydration and transepidermal water loss (TEWL) were measured periodically throughout the experiment. To investigate the underlying mechanisms, we analyzed the mRNA expression of genes related to hydration and barrier function, quantified skin hyaluronic acid (HA) levels via ELISA, and performed immunohistochemical staining. Oral SEP administration increased skin hydration and decreased TEWL, suggesting improved barrier function. Gene expression analyses revealed upregulation of Has1–3, Col1a1, Col3a1, Tgf‐β1, Flg, and Cers2, along with downregulation of Hyal1 and Acer1. These effects were supported by higher hyaluronic acid content and confirmed by altered protein expression of HAS2, HYAL1, and TGF‐β1. No significant changes were observed in body weight, food intake, or organ weights, and no adverse effects were observed at tested doses, supporting the safety of oral SEP administration. Overall, these findings suggest that orally administered SEP improves skin hydration and strengthens barrier integrity by regulating both molecular and tissue‐level pathways, highlighting its potential as a functional food ingredient for skin health.

Immunohistochemical staining of dorsal skin tissues for HAS2, HYAL1, and TGF‐β1. Oral administration of SEP increased the expression of HAS2 and TGF‐β1 in a dose‐dependent manner, while reducing HYAL1 expression. These findings indicate that SEP promotes hyaluronic acid synthesis and extracellular matrix remodeling. The results support the moisturizing and barrier‐enhancing effects of SEP at the protein level.