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Completed

NCT Number: NCT07184905

Oral Bifidobacterium Longum for Skin Barrier Dysfunction in Obesity

This clinical trial aims to evaluate the safety and efficacy of oral Bifidobacterium longum supplementation for treating obesity-induced skin barrier impairment in individuals aged 18-40 with BMI ≥30, compared to healthy controls. The study focuses on the following questions:

Can oral Bifidobacterium supplementation reduce skin barrier damage (measured by transepidermal water loss/TEWL) in obese participants? Does modulation of gut microbiota with Bifidobacterium longum impact skin barrier function and systemic inflammation?

Researchers will compare outcomes across two groups:

* Intervention Group (Obese): Oral Bifidobacterium longum capsules * Placebo Control Group (Obese): Oral inactive Bifidobacterium longum (heat-killed)

Participant Procedures:

Take daily oral capsules (Bifidobacterium longum or inactive strain) for 4 weeks Undergo non-invasive skin testing (TEWL measurements) at baseline and study completion Provide blood, stool, and skin swab samples for inflammation and microbiome analyses Complete weekly check-ins to report adverse effects (e.g., gastrointestinal discomfort, skin irritation)

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Key information

Conditions

Skin Barrier to Water Loss Communicable Diseases Disease Attributes Infections Microbial Colonization Pathologic Processes Pathological Conditions, Signs and Symptoms

Age range

18 year–40 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Shenzhen People's Hospital

Shenzhen, Guangdong, 518020, China

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Oral administration of inactive Bifidobacterium longum group

Biological

1×10^11 CFU of inactive Bifidobacterium longum was given orally once daily for one month

Oral Bifidobacterium longum group

Biological

1×10^11 CFU of Bifidobacterium longum was given orally once daily for one month

Primary outcomes

  1. Mean change in transepidermal water loss (TEWL, g/h/m²) on the volar forearm from baseline to 1 month after intervention, measured by Tewameter

    Time frame: Baseline through 1 month after intervention

    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.

Secondary outcomes

  1. Change in gut Bifidobacterium longum abundance and metabolites in fecal samples

    Time frame: Baseline through 1 month after intervention

    Stool samples will be collected at baseline and after intervention. Microbial abundance will be assessed by 16S rRNA sequencing, and metabolites will be profiled using targeted metabolomics. Data will be reported as relative abundance (%) and metabolite concentrations (µM).

  2. Change in serum inflammatory cytokine levels

    Time frame: Baseline through 1 month after intervention

    Serum samples will be collected before and after Bifidobacterium longum treatment. Cytokine levels (e.g., IL-6, TNF-α, IL-22) will be measured by ELISA, reported as pg/mL.

  3. Change in skin hydration measured by Corneometer

    Time frame: Baseline through 1 month after intervention

    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.

  4. Change in clinical skin health score

    Time frame: Baseline through 1 month after intervention

    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.

  5. Change in body weight and BMI

    Time frame: Baseline through 1 month after intervention

    Participants' body weight (kg) and BMI (kg/m²) will be recorded at baseline and post-intervention. Data will be reported as mean change.

Sponsors and collaborators

Lead sponsor

Shenzhen People's Hospital

Other

Registry information

Official study title

Effect of Oral Bifidobacterium Longum on Skin Barrier Dysfunction in Obesity: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Sep 22, 2025
Registry last updated
Dec 3, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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