The purpose of this clinical trial is to assess the skin hydration and transepidermal water loss improvement, pruritus relief, and microbiome alteration effects of a Lactobacillus sp. product (Lactobarriome 5% cream) compared to a placebo cream to prove the skin improvement effects of Lactobarriome 5%, which is a nature-friendly material derived from intravaginal microflora that can replace chemical components commonly used as ingredients for existing cosmetics.

The impact of Lactobarriome 5% cream, formulated with LP51 culture filtrate, on dry skin was assessed through a 4-week double-blind clinical trial. Participants were selected based on predefined inclusion and exclusion criteria. Using a simple randomization method, participants were assigned to either the experimental group (receiving the test formulation) or the control group (receiving a placebo). The products were applied twice daily-morning and evening-to a 3 cm area on both the proximal and distal sides of the designated arm's crook. Clinical evaluations were conducted at baseline, as well as after 2 weeks and 4 weeks of product use. These assessments included visual inspections, subjective pruritus evaluations, skin hydration levels, and transepidermal water loss (TEWL) measurements, all performed by a skincare professional. Furthermore, magnified images were captured using a Folliscope, and skin samples were collected to analyze microbial changes post-treatment. Before application, the designated arm was washed with water and allowed to rest for 30 minutes under controlled conditions (22±2°C, 50±10% relative humidity).

Inclusion Criteria:

• Healthy participants, including men and women, aged 19-70
• Without acute or chronic diseases (excluding atopic dermatitis)
• Individuals suffering from dry skin and itchiness in the test area (crook of the arm)
• Those with objectively proven skin barrier damage demonstrated by a transepidermal water loss (TEWL) value of ≥12 g/h/m² and a skin hydration value below 35 (Corneometer measurement)
• Individuals who provided voluntary informed consent
• Those who agreed to comply with study visits and observations

Exclusion Criteria:

• Individuals with active skin diseases requiring treatment
• Those with an ESIF score >6
• Individuals with a history of antibiotic, steroid, immunosuppressant, antihistamine, or retinoid use, or phototherapy within the last 4 weeks
• Individuals who used skin disease-related supplements or moisturizers within 2 weeks
• Those participating in other clinical trials within the last 4 weeks
• Individuals with frequent exposure to UV light
• Pregnant or lactating women
• Those planning pregnancy during the trial period
• Any other factors deemed unsuitable by the investigator