The goal of this clinical trial is to assess the effects of household detergents and hand disinfectants on human skin barrier integrity among healthy adult volunteers.

The main questions it aims to answer are:

• How does exposure to household detergents and hand disinfectants impact skin barrier function?
• Are there differences in skin barrier disruption between various types of cleaning agents and disinfectants?

Participants will:

Undergo patch testing with controlled amounts of household detergents and hand disinfectants on a small area of their skin.

Be monitored for adverse reactions during and after exposure. Have their skin barrier integrity assessed using electrical impedance spectroscopy at multiple time points post-exposure.

If there is a comparison group:

Researchers will compare the effects of different types of cleaning agents, hand disinfectants, and their ingredients on skin barrier integrity to determine variations in their impact.

1. Core Message:

   Understanding the effects of detergent and disinfectant exposure on skin barrier integrity is crucial for public health, particularly given their widespread use.

2. Supporting Information:

   Studies suggest an association between cleaning agents and skin barrier disruption. Skin barrier function can be assessed using various methods, including electrical impedance spectroscopy (EIS).

3. Key Points:

   Scientific Question: Investigate how household detergent, hand disinfectant, and their ingredients exposure affect skin barrier function.

   Proposed Intervention: Conduct controlled human skin exposure experiments with properly diluted household detergents, hand disinfectants, and their ingredients.

   Scientific Basis: Previous research indicates potential risks associated with cleaning agent exposure and validates EIS as a suitable assessment tool.

4. Objectives:

   Hypothesis: Household detergent and hand disinfectant exposure damage skin barrier integrity.

   Primary Objective: Demonstrate the effect of cleaning agent exposure on skin barrier function.

5. Study Population and Procedures:

   Inclusion criteria: Healthy adult volunteers aged 18-65. Exclusion criteria: Individuals with chronic skin conditions, allergies, or recent systemic therapy.

   Recruitment through ongoing processes and physician referrals. Informed consent emphasizing voluntary participation and the right to withdraw.

6. Statistics and Methodology:

   Sample size: 50 participants. Intervention: Participants will be exposed to controlled amounts of household detergents, hand disinfectants, and their ingredients.

   Assessment methods: EIS for skin barrier integrity evaluation. Statistical methods: Analysis using appropriate tests to detect significant differences.

7. Regulatory Aspects and Safety:

   Compliance with ethical guidelines and local regulations. Immediate reporting of adverse events and regular safety monitoring.

8. Quality Control and Data Protection:

   Measures include personnel training, SOPs, and data security protocols. Data is handled with discretion and stored securely.

9. Monitoring and Registration:

   Regular monitoring by research institutions (SIAF and UZH). This study will be registered with the Swiss National Clinical Trial Portal (SNCTP via BASEC) and ClinicalTrials.gov.

10. Funding / Publication / Declaration of Interest:

Funding from Swiss National Foundation (Prof. Cezmi Akdis) and SciBase. Commitment to transparency, open science, and conflict-free reporting. Multicentre collaboration between SIAF and Department of Dermatology, UZH.

Inclusion Criteria:

• The study population will consist of healthy adult volunteers; 1. age between18 and 65 years, 2. Generally healthy and able to provide written informed consent. The choice of healthy adult volunteers without pre-existing skin conditions on site or allergies against tested products is justified.

Exclusion Criteria:

1. Severe dermatitis, eczema, psoriasis, or other chronic skin conditions.
2. History of hypersensitivity or allergies to tested product ingredients.
3. Current or recent systemic therapy for a skin condition in the past six months.
4. Pregnant or breastfeeding individuals.
5. Use of investigational drugs or participation in another trial in the last 30 days.
6. History of skin cancer or malignancies in the study area.
7. Significant sunburn, open wounds, or active skin infections in the study area.
8. Any medical condition that, per the investigator, might compromise safety or confound results.
9. Inability to follow study instructions or attend required clinic visits.
10. Gender Balance: To ensure gender balance, efforts will be made to recruit an equal number of male and female participants.