Topical Lactobacillus Crispatus for Skin Barrier Dysfunction in Obesity

Evaluation of the Safety and Efficacy of Topical Application of Lactobacillus Crispatuson the Forearm for Treating Obesity-Induced Skin Barrier Dysfunction: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

This clinical trial aims to evaluate the safety and efficacy of topical application of Lactobacillus crispatuson the forearm for treating obesity-induced skin barrier impairment in individuals aged 18-45 with BMI ≥25. The study focuses on the following questions:

Can topical application of Lactobacillus crispatusreduce skin barrier damage, as measured by transepidermal water loss (TEWL), in obese participants?

Does modulation of the skin microbiota with Lactobacillus crispatusimprove skin barrier function, hydration, and reduce local inflammation?

Is the topical intervention safe and well-tolerated, with minimal adverse effects?

Preliminary data from obese volunteers and mouse models revealed significantly elevated TEWL and reduced Lactobacillusabundance in the skin microbiome of obese individuals, supporting the investigation of probiotic restoration.

Researchers will compare outcomes across two groups:

Intervention Group (Obese) : Daily topical application of active Lactobacillus crispatussolution (1×10⁷ CFU in 3 mL) to a 3-cm diameter area on both forearms.

Placebo Control Group (Obese) : Daily topical application of inactivated Lactobacillus crispatussolution (identical appearance and volume).

Participant Procedures:

Apply the assigned topical solution daily to the forearm for 4 weeks.

Undergo non-invasive skin testing, including TEWL measurements and skin hydration assessments, at baseline and study completion (Week 4).

Provide skin swab samples at baseline and Week 4 for microbiome analysis (16S rRNA sequencing) and inflammation marker detection (e.g., IL-1β, TNF-α via ELISA).

Complete weekly check-ins to report adverse effects (e.g., skin irritation, erythema) and adherence, with follow-ups at Weeks 1, 2, and 3.

Maintain a daily electronic or paper diary to record application time, dose, and any skin reactions.

Study Overview

• Status: Completed
• Conditions: Microbial Colonization; Skin Barrier to Water Loss
• Intervention / Treatment: Biological: Topical L. crispatus Treatment Group; Biological: Topical Inactivated Lactobacillus crispatus Application Group

• Study Type: Interventional
• Enrollment (Actual): 98
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Guangdong
    • Shenzhen, Guangdong, China
      • ShenZhen People's Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• 1. Meets 2020 WHO BMI classification:
• a. Normal weight (18.5-24.9 kg/m²)
• b. Overweight (25-29.9 kg/m²)
• c. Obesity (≥30 kg/m²)
• 2. Presence of skin barrier impairment (e.g., dryness, erythema, desquamation, or itching)
• 3. Age 18-40 years
• 4. Generally good health (no active systemic diseases)
• 5. Able and willing to provide written informed consent
• 6. No use of oral/topical medications or probiotics within 6 months prior
• 7. No active skin disease or traumatic skin lesions

Exclusion Criteria:

• 1. Known allergy or hypersensitivity to probiotics, placebo, or investigational product
• 2. Active skin disease (e.g., psoriasis, eczema, infection) requiring treatment
• 3. Severe medical conditions:
• a. Cardiopulmonary disease (NYHA class III/IV)
• b. Uncontrolled diabetes (HbA1c >9%)
• c. Autoimmune disorders
• 4. Pregnant or breastfeeding women
• 5. Any condition that may interfere with protocol compliance (per investigator judgement), including:
• a. Inability to understand study procedures
• b. History of poor clinical trial adherence
• 6. Concurrent participation in other interventional trials

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Topical L. crispatus Treatment Group	Biological: Topical L. crispatus Treatment Group; Once daily, 3mL of Lactobacillus crispatus solution was applied to the bilateral forearms at a diameter of 3cm 10cm from the carpal wrinkles
Sham Comparator: Topical Inactivated Lactobacillus crispatus Application Group	Biological: Topical Inactivated Lactobacillus crispatus Application Group; Once daily, 3mL of inactive Lactobacillus crispatus solution was applied to the bilateral forearms at a diameter of 3cm 10cm from the carpal wrinkles

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean change in transepidermal water loss (TEWL, g/h/m²) on the volar forearm from baseline to 1 month after intervention, measured by Tewameter	TEWL will be assessed on the volar aspect of the forearm using a Tewameter device under standardized environmental conditions (controlled temperature and humidity). At each time point, TEWL will be measured at three predefined skin sites on the volar forearm, and the average value will be used. The primary outcome will be the mean change in TEWL (g/h/m²) from baseline (Day 0) to 1 month after intervention. Lower TEWL values indicate improved skin barrier function.	Baseline through 1 month after intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in skin hydration measured by Corneometer	Skin hydration will be assessed using a Corneometer device. Outcomes will be expressed as mean skin capacitance values (arbitrary units) at baseline and post-intervention.	Baseline through 1 month after intervention
Change in clinical skin health score	Skin dryness, scaling, erythema, itching, and allergy-related symptoms will be evaluated using a standardized Skin Dryness Scoring System. Data will be reported as mean score change from baseline.	Baseline through 1 month after intervention
Change in body weight and BMI	Participants' body weight (kg) and BMI (kg/m²) will be recorded at baseline and post-intervention. Data will be reported as mean change.	Baseline through 1 month after intervention

Collaborators and Investigators

• Sponsor: Shenzhen People's Hospital

Study record dates

Study Major Dates

• Study Start (Actual): December 15, 2025
• Primary Completion (Actual): December 15, 2025
• Study Completion (Actual): December 15, 2025

Study Registration Dates

• First Submitted: November 25, 2025
• First Submitted That Met QC Criteria: November 25, 2025
• First Posted (Estimated): December 5, 2025

Study Record Updates

• Last Update Posted (Actual): December 24, 2025
• Last Update Submitted That Met QC Criteria: December 22, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Disease Attributes; Infections; Pathological Conditions, Signs and Symptoms; Communicable Diseases
• Other Study ID Numbers: LL-KY-2025229-02

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No