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

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

30

Phase

  • 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

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
Intervention / Treatment
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

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

University of Split, School of Medicine

Collaborators

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)

March 1, 2026

Primary Completion (Estimated)

June 1, 2026

Study Completion (Estimated)

April 25, 2027

Study Registration Dates

First Submitted

December 2, 2025

First Submitted That Met QC Criteria

December 2, 2025

First Posted (Actual)

December 16, 2025

Study Record Updates

Last Update Posted (Actual)

February 13, 2026

Last Update Submitted That Met QC Criteria

February 12, 2026

Last Verified

November 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID 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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