Topical Peptide Effects on Facial Skin Barrier Function

The goal of this clinical trial is to evaluate whether a topical face cream containing the peptide Acetyl Hexapeptide-37 improves skin hydration and strengthens the skin barrier compared to a placebo cream in healthy adult participants. The study uses a split-face design, in which one side of the face is treated with the peptide cream and the other side with a placebo (a cream without the active ingredient). The main questions it aims to answer are: * Does the peptide cream improve skin hydration and reduce transepidermal water loss compared to placebo? * Does the peptide cream affect skin erythema or cause irritation? * How do participants rate the comfort and tolerability of the peptide cream? Researchers will compare the treated and placebo sides of the face to assess differences in skin barrier function and tolerability. Participants will: * Attend a baseline visit for assessment of facial skin parameters, including hydration, transepidermal water loss, and erythema * Apply the peptide cream to one side of the face and the placebo cream to the other side once daily for 4 weeks * Attend weekly follow-up visits for non-invasive skin measurements * Record any skin sensations (e.g., stinging, tightness) or adverse effects throughout the study