Glycyrrhetinic Acid and Acute Irritant Dermatitis

February 12, 2026 updated by: University of Split, School of Medicine

Effects of Glycyrrhetinic Acid on Human Skin in an Acute Irritant Contact Dermatitis Model

Irritant dermatitis is one of the most common inflammatory skin disorders, caused by exposure to external substances that induce inflammation and immune activation. Standard management includes avoidance of irritants, restoration of the skin barrier using emollients, and the application of anti-inflammatory drugs such as topical corticosteroids. However, due to the risks associated with long-term corticosteroid use, there is an interest in developing emollient formulations enriched with bioactive compounds possessing anti-inflammatory properties. Among those promising compounds is glycyrrhetinic acid.

18β-Glycyrrhetinic acid, a bioactive component of licorice root extract, exhibits potent anti-inflammatory and antioxidant effects. Topical application has demonstrated beneficial outcomes in conditions such as atopic dermatitis, acne, pruritus, and UVB-induced skin damage. Its proposed mechanisms of action include inhibition of key inflammatory enzymes (COX, 5-LOX, iNOS) and promotion of skin regeneration through stimulation of aquaporin-3 expression and enhancement of epidermal turnover.

Topical application of formulations containing 18β-glycyrrhetinic acid will improve skin parameter disturbances caused by irritation induced with sodium lauryl sulfate.

This study aims to evaluate the effects of 18β-glycyrrhetinic acid on human skin parameters in an acute irritant dermatitis model induced by sodium lauryl sulfate, providing further insight into its potential role as an anti-inflammatory and barrier-restoring agent.

Funding:

Funded by the European Union - NextGenerationEU. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
30

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Croatia
      • Split, Croatia, 21000
        • University of Split School of Medicine
        • Principal Investigator:
          • Dario Leskur, asst. prof., MPharm, PhD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Healthy adult participants aged 18 years or older, of any sex.
  • Intact, healthy skin at the test sites.
  • No use of systemic or topical corticosteroids, immunomodulators, or antihistamines within the previous three months.
  • No use of topical emollients on the test sites within the previous seven days.

Exclusion Criteria:

  • Pregnant women, women suspected of being pregnant, and breastfeeding women.
  • Non-compliance with the study protocol.
  • Voluntary withdrawal or personal decision not to continue participation.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Other: No Treatment and Intact skin
No topical product will be applied. Intact skin.
Other: No Treatment
Designated test area with no topical application after irritation (on the irritated forearm) and on corresponding intact skin (on the non-irritated forearm). Serves as a baseline reference for spontaneous recovery and physiological skin variability.
Placebo Comparator: Placebo and Intact skin
Topical placebo formulation identical in appearance and vehicle composition to the active preparation but without glycyrrhetinic acid. Used to control for vehicle effects on skin parameters. Intact skin.
Other: Placebo

Topical formulation identical in composition to the active preparations but without glycyrrhetinic acid.

Used to evaluate the effect of the formulation vehicle on skin parameters. Applied daily to designated test sites on both irritated and intact forearm areas for the duration of the study.
Experimental: Glycyrrhetinic Acid (lower dose) and Intact skin
Topical formulation containing a lower concentration of 18β-glycyrrhetinic acid. Designed to evaluate the dose-dependent effect of the active compound on intact skin parameters. Intact skin.
Other: Lower Dose Glycyrrhetinic Acid

Topical formulation containing a lower concentration of 18β-glycyrrhetinic acid.

Designed to assess the effects of the active compound at a lower dose on skin barrier recovery and skin parameters following SLS-induced irritation.

Applied daily to designated test sites on both irritated and intact forearm areas for the duration of the study.
Experimental: Glycyrrhetinic Acid (higher dose) and Intact skin
Topical formulation containing a higher concentration of 18β-glycyrrhetinic acid. Used to assess whether a higher dose enhances anti-inflammatory and barrier-restoring effects compared with the lower dose and placebo.
Other: Higher Dose Glycyrrhetinic Acid

Topical formulation containing a higher concentration of 18β-glycyrrhetinic acid.

Designed to assess the effects of the active compound at a lower dose on skin barrier recovery and skin parameters following SLS-induced irritation.

Applied daily to designated test sites on both irritated and intact forearm areas for the duration of the study.
Other: No Treatment and Irritation
No topical product will be applied. SLS induced skin irritation.
Other: No Treatment
Designated test area with no topical application after irritation (on the irritated forearm) and on corresponding intact skin (on the non-irritated forearm). Serves as a baseline reference for spontaneous recovery and physiological skin variability.
Procedure: SLS induced irritation

Skin irritation will be induced on 4 defined test sites on one forearm (randomly selected forearm) using 60 uL of 1% w/v sodium lauryl sulfate (SLS) aqueous solution under occlusion for a defined period to create a controlled model of acute irritant dermatitis.

The contralateral forearm will remain untreated and serve as intact skin for comparison.

Following the induction phase, all test products (placebo and active formulations) will be applied to both irritated and intact sites according to the treatment allocation.
Placebo Comparator: Placebo and Irritation
Topical placebo formulation identical in appearance and vehicle composition to the active preparation but without glycyrrhetinic acid. Used to control for vehicle effects on skin parameters. SLS induced skin irritation.
Other: Placebo

Topical formulation identical in composition to the active preparations but without glycyrrhetinic acid.

Used to evaluate the effect of the formulation vehicle on skin parameters. Applied daily to designated test sites on both irritated and intact forearm areas for the duration of the study.

Procedure: SLS induced irritation

Skin irritation will be induced on 4 defined test sites on one forearm (randomly selected forearm) using 60 uL of 1% w/v sodium lauryl sulfate (SLS) aqueous solution under occlusion for a defined period to create a controlled model of acute irritant dermatitis.

The contralateral forearm will remain untreated and serve as intact skin for comparison.

Following the induction phase, all test products (placebo and active formulations) will be applied to both irritated and intact sites according to the treatment allocation.
Experimental: Glycyrrhetinic Acid (lower dose) and Irritation
Topical formulation containing a lower concentration of 18β-glycyrrhetinic acid. Designed to evaluate the dose-dependent effect of the active compound on skin recovery and barrier function after irritation. SLS induced skin irritation.
Other: Lower Dose Glycyrrhetinic Acid

Topical formulation containing a lower concentration of 18β-glycyrrhetinic acid.

Designed to assess the effects of the active compound at a lower dose on skin barrier recovery and skin parameters following SLS-induced irritation.

Applied daily to designated test sites on both irritated and intact forearm areas for the duration of the study.

Procedure: SLS induced irritation

Skin irritation will be induced on 4 defined test sites on one forearm (randomly selected forearm) using 60 uL of 1% w/v sodium lauryl sulfate (SLS) aqueous solution under occlusion for a defined period to create a controlled model of acute irritant dermatitis.

The contralateral forearm will remain untreated and serve as intact skin for comparison.

Following the induction phase, all test products (placebo and active formulations) will be applied to both irritated and intact sites according to the treatment allocation.
Experimental: Glycyrrhetinic Acid (higher dose) and Irritation
Topical formulation containing a higher concentration of 18β-glycyrrhetinic acid. Used to assess whether a higher dose enhances anti-inflammatory and barrier-restoring effects compared with the lower dose and placebo. SLS induced skin irritation
Other: Higher Dose Glycyrrhetinic Acid

Topical formulation containing a higher concentration of 18β-glycyrrhetinic acid.

Designed to assess the effects of the active compound at a lower dose on skin barrier recovery and skin parameters following SLS-induced irritation.

Applied daily to designated test sites on both irritated and intact forearm areas for the duration of the study.

Procedure: SLS induced irritation

Skin irritation will be induced on 4 defined test sites on one forearm (randomly selected forearm) using 60 uL of 1% w/v sodium lauryl sulfate (SLS) aqueous solution under occlusion for a defined period to create a controlled model of acute irritant dermatitis.

The contralateral forearm will remain untreated and serve as intact skin for comparison.

Following the induction phase, all test products (placebo and active formulations) will be applied to both irritated and intact sites according to the treatment allocation.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Transepidermal water loss
Time Frame: Baseline, Irritation Assessment, 3rd, 6th, 8th and 10th day of the treatment
Tewameter will be used to assess skin barrier function as a measurement of the water loss (g/m2/h).
Baseline, Irritation Assessment, 3rd, 6th, 8th and 10th day of the treatment
Hydration
Time Frame: Baseline, Irritation Assessment, 3rd, 6th, 8th and 10th day of the treatment
Corneometer will be used to estimate skin dryness. It is a relative measurement and uses arbitrary units (AU).
Baseline, Irritation Assessment, 3rd, 6th, 8th and 10th day of the treatment
Erythema
Time Frame: Baseline, Irritation Assessment, 3rd, 6th, 8th and 10th day of the treatment
Mexameter will be used to assess erythema. It is a relative measurement and uses arbitrary units (AU).
Baseline, Irritation Assessment, 3rd, 6th, 8th and 10th day of the treatment
Skin elasticity
Time Frame: Baseline, Irritation Assessment, 3rd, 6th, 8th and 10th day of the treatment
Cutometer will be used to assess skin elasticity.
Baseline, Irritation Assessment, 3rd, 6th, 8th and 10th day of the treatment

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Split, School of Medicine

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
European Union

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 25, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 2, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 2, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
December 16, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 13, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 12, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
November 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2181-198-03-04-25-0072
  • IP-UNIST-35 (Other Grant/Funding Number: Funded by the European Union - NextGenerationEU)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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