Licorice root is derived from the plant Glycyrrhiza glabra, a perennial herb native to parts of Europe and Asia. The root has a long history of use in traditional medicine systems and is valued for its diverse range of bioactive compounds. These compounds contribute to its biological activity and relevance in modern research.

Ingredient Overview: Licorice Root

Key constituents of licorice root include:

• Glycyrrhizin and glycyrrhetinic acid
• Flavonoids such as liquiritin and isoliquiritigenin
• Chalcones and saponins

These substances are commonly extracted using water or alcohol-based methods to preserve their stability and activity.

Traditional and Modern Applications

Licorice root has been traditionally used to support skin health, digestive balance, and respiratory comfort. In topical and oral formulations, it appears in creams, serums, and supplements aimed at general wellness. Modern formulations often standardize extracts to specific active compounds to ensure consistent dosing.

In skincare-related products, licorice root is frequently included for its perceived soothing and balancing properties. This has led to its use in products designed for uneven skin tone and surface irritation, without being limited to a single condition.

Common product forms include:

• Topical creams and gels
• Serums and cosmetic blends
• Oral extracts and capsules

Safety and General Considerations

Licorice root is generally considered safe when used in controlled amounts and standardized preparations. Safety assessments focus on dosage, duration of use, and the concentration of glycyrrhizin, which can influence systemic effects if consumed excessively. Topical use typically involves lower exposure levels compared to oral intake.

Licorice root is a well-studied botanical ingredient rich in bioactive compounds, widely used in acne treatment and skincare. Its established presence in skincare and wellness formulations makes it a relevant ingredient for research related to acne and skincare.

Mechanism of Action and Claimed Benefits of Licorice Root

Bioactive Compounds and Skin Interaction

Licorice root contains several active compounds that interact with skin cells and surface structures. Glycyrrhetinic acid and flavonoids are the most frequently studied components in skincare research. These substances show activity at the epidermal level and influence processes linked to skin balance and appearance.

Primary actions observed in laboratory and formulation studies include:

• Interaction with inflammatory signaling pathways
• Modulation of sebum-related activity
• Influence on microbial balance at the skin surface

These actions explain why licorice root appears in products designed for acne and general skincare.

Anti-Inflammatory and Soothing Properties

Research indicates that licorice root compounds can reduce markers associated with skin inflammation. This effect is mainly linked to the inhibition of enzymes and mediators involved in redness and swelling. By limiting these responses, licorice root may support calmer skin and reduce visible irritation often associated with acne-prone areas.

Reported skin-related benefits include:

• Reduced redness and sensitivity
• Support for skin barrier comfort
• Improved visual uniformity of the skin surface

These outcomes are relevant for skincare routines that aim to maintain stable skin conditions.

Effects on Pigmentation and Skin Tone

Certain flavonoids in licorice root affect pathways related to melanin production. This mechanism has attracted interest in cosmetic research, especially for post-acne marks and uneven skin tone. By influencing melanin-related enzymes, licorice root may support a more even-looking complexion over time.

Claimed Benefits in Skincare Products

Manufacturers often highlight licorice root for its calming, balancing, and appearance-supporting effects. These claims focus on surface-level improvements rather than systemic action.

Licorice root acts through multiple skin-related mechanisms, including inflammation modulation, interaction with surface microbes, and influence on pigmentation pathways. These actions form the basis for its claimed benefits in acne and skincare formulations.

Why Licorice Root Is Studied for Acne Treatment and Skincare

Relevance to Acne-Related Skin Processes

Acne development involves multiple skin processes, including inflammation, excess sebum, and microbial imbalance. Researchers study licorice root because its bioactive compounds interact with several of these processes at the skin level. This broad activity profile makes the ingredient suitable for investigation in acne and general skincare research.

Scientific interest focuses on the ability of licorice root to influence:

• Inflammatory mediators linked to visible skin changes
• Surface bacteria associated with acne-prone skin
• Skin responses to environmental and internal stressors

These factors are central to acne formation and persistence.

Historical Use and Research Continuity

Licorice root has a long record of use in traditional skin applications, which supports modern research interest. Historical topical use for skin comfort and appearance encouraged researchers to examine its effects under controlled conditions. This continuity between traditional practice and laboratory research strengthens its relevance for scientific study.

Modern research builds on:

• Ethnobotanical records of skin use
• Early pharmacological evaluations
• Advances in extraction and formulation methods

This progression allows more precise analysis of licorice root activity in skincare.

Compatibility With Topical Formulations

Licorice root extracts integrate well into modern skincare formulations used in acne research. The ingredient shows stability in creams, gels, and serums, which enables consistent application in clinical and cosmetic studies. This practical advantage supports its repeated selection for acne-related trials.

Key formulation advantages include:

• Good skin tolerability in tested concentrations
• Compatibility with other common skincare ingredients
• Suitability for long-term topical use in studies

Consumer and Market Interest

High consumer demand for plant-based skincare ingredients also drives research into licorice root for acne. Researchers aim to verify common product claims through structured studies and measurable outcomes.

Licorice root is studied for acne and skincare due to its interaction with core acne-related processes, historical skin use, formulation compatibility, and strong consumer interest in plant-based solutions.

How Studies on Licorice Root Are Designed and Evaluated

Common Study Designs

Clinical and experimental studies on licorice root for acne and skincare use a range of structured research designs. Researchers select the design based on the research question, formulation type, and target outcome. Most studies focus on topical application, though some include oral intake as part of broader skin assessments.

Frequently used study designs include:

• Randomized controlled trials with topical formulations
• Comparative studies against placebo or standard skincare agents
• In vitro and ex vivo skin model experiments
• Small-scale pilot studies in human volunteers

These approaches allow researchers to isolate the effects of licorice root under controlled conditions.

Participant Selection and Treatment Protocols

Human studies usually enroll participants with mild to moderate acne or visible skin concerns. Researchers define inclusion and exclusion criteria to limit confounding factors such as concurrent medication use or severe dermatological conditions. Treatment periods often range from two to twelve weeks, depending on the study goal.

Protocols typically define:

• Concentration of licorice root extract
• Frequency of application or intake
• Duration of treatment and follow-up

This structure ensures consistency across participants.

Outcome Measures and Data Collection

Researchers measure outcomes using both clinical assessments and instrumental methods. Visual grading scales remain common, but many studies also include objective tools to increase reliability.

Common outcome measures include:

• Lesion count and severity scores
• Redness and skin irritation scales
• Sebum production measurements
• Skin tone and pigmentation analysis

Participant self-assessments often complement clinical data.

Data Analysis and Interpretation

Statistical analysis compares baseline and post-treatment results to identify meaningful changes. Researchers assess significance, effect size, and consistency across outcome measures to determine relevance.

Studies on licorice root for acne and skincare rely on controlled designs, defined protocols, and both subjective and objective outcome measures to evaluate skin-related effects with consistency and transparency.

Clinical Studies of Licorice Root for Acne and Skincare

Below is a structured overview of the leading clinical and clinical-type research on licorice root (especially its bioactive components such as licochalcone A) for acne and skincare. These studies describe effects, measured outcomes, and links to sources when available.

Study: Licochalcone A in Combination with Salicylic Acid for Mild Facial Acne

Short Overview: A multicenter, prospective clinical trial evaluated the daily use of a topical regimen containing licochalcone A, salicylic acid, and related actives in adults with mild acne. Subjects applied a morning fluid and a bedtime cream over 8 weeks.

Measured Outcome: Significant reduction in acne severity (Global Acne Grading System), total comedones and papules counts, and mean sebum production after 4 and 8 weeks of use. At 8 weeks, comedones and papules decreased 64% and 71%, respectively, while sebum dropped about 52% from baseline.

Link to the Study: https://pubmed.ncbi.nlm.nih.gov/32099436/

Study: Double-Blinded, Vehicle-Controlled Topical Licochalcone A Study (Mukhtasar)

Short Overview: In a randomized, double-blind, vehicle-controlled clinical study, a moisturizer containing licochalcone A with other partners (e.g., l-carnitine, 1,2-decanediol) was evaluated in mild-to-moderate acne patients. Outcomes included lesion counts, sebum levels, hydration, and quality of life.

Measured Outcome: This class of study consistently found reductions in inflammatory lesion counts, total acne severity, and sebum levels compared to control formulations.

Link to the Study: Clinical details summarized in narrative review (Karger) and PubMed abstract summaries. Karger Publishers

Study: Inhibitory Effect of Licochalcone A on Acne Inflammation (Preclinical Step With Clinical Relevance)

Short Overview: Although primarily preclinical, this investigation explored how licochalcone A modulates immune responses to Cutibacterium acnes (formerly Propionibacterium acnes), a key bacterium in acne. Applied topically in models of P. acnes-induced inflammation, licochalcone A reduced key mediators of the inflammatory cascade, such as IL-1β.

Measured Outcome: Reduction in inflammasome activation (NLRP3), lowered caspase-1 and IL-1β production in treated tissue. While not a direct human clinical trial, this mechanistic data supports outcomes seen in clinical formulations.

Link to the Study: https://pubmed.ncbi.nlm.nih.gov/30281174/

Study: Supplemental Clinical Observations Combining LicA with Adapalene

Short Overview: A smaller randomized controlled trial evaluated the addition of a licochalcone A sunscreen to adapalene therapy for acne and post-acne pigmentation. Findings indicated improved acne severity and pigmentation parameters when LicA was added.

Measured Outcome: Reduction in inflammatory and noninflammatory lesion counts and improvements in post-acne hyperpigmentation compared with standard treatments alone.

Link to the Study: Frontiers in Pharmacology

Summary of Clinical Evidence

Current clinical evidence for licorice root (typically via its component licochalcone A) for acne and skincare shows:

• Topical licorice-derived formulations consistently reduced acne lesion counts, sebum output, and severity scores in mild to moderate acne patients.
• Combination regimens with salicylic acid or adapalene appear more effective than either alone, pointing to a useful adjunct role.
• Mechanistic research supports anti-inflammatory and antimicrobial actions relevant to acne pathogenesis.

Overall, licorice root components demonstrate clinical and preclinical promise for acne and skin health, though larger, stand-alone, placebo-controlled trials specifically isolating licorice extract are still limited.

Limitations of Existing Research on Licorice Root for Acne Treatment and Skincare

Study Design and Sample Size Constraints

Many studies on licorice root for acne and skincare involve small sample sizes and short study durations. Limited participant numbers reduce statistical power and make it difficult to generalize results to broader populations. Short treatment periods also restrict evaluation of long-term effects and sustainability of observed outcomes.

Common design-related limitations include:

• Pilot or exploratory study frameworks
• Short follow-up periods
• Lack of diverse demographic representation

These factors can influence the reliability of conclusions.

Use of Combination Formulations

A significant portion of clinical research evaluates licorice root as part of multi-ingredient formulations. While this reflects real-world product use, it complicates attribution of observed effects solely to licorice root. Active ingredients such as salicylic acid or retinoids may independently affect acne-related outcomes.

As a result:

• Isolated effects of licorice root remain unclear
• Synergistic versus primary actions are difficult to separate
• Dose–response relationships are not well defined

This limits precise assessment of licorice root efficacy.

Variability in Extracts and Standardization

Licorice root extracts vary widely in composition depending on source, processing, and standardization. Studies often use different extract types, concentrations, or specific compounds such as licochalcone A. This variability reduces comparability across studies.

Reported challenges include:

• Inconsistent reporting of active compound levels
• Differences in extraction methods
• Limited transparency in proprietary formulations

Such variation affects reproducibility.

Outcome Measurement and Reporting

Some studies rely heavily on subjective assessments or non-standardized scoring systems. Visual grading scales and self-reported outcomes introduce potential bias, especially in unblinded or partially blinded studies. Objective tools are not always used consistently.

Gaps in Long-Term and Comparative Research

There is a lack of long-term, large-scale trials comparing licorice root directly with standard acne treatments. This limits understanding of its relative effectiveness and safety profile over extended use.

Existing research on licorice root for acne and skincare shows promising trends but remains limited by small study sizes, combination formulations, extract variability, and short-term designs, highlighting the need for more rigorous and standardized clinical trials.

Summary of Clinical Studies on Licorice Root for Acne Treatment and Skincare

Overall Evidence Profile

Clinical research on licorice root for acne and skincare suggests measurable benefits, primarily when used in topical formulations. Most human studies focus on standardized licorice-derived compounds, especially licochalcone A, rather than whole-root extracts. These studies consistently examine mild to moderate acne and related skin features.

Across published trials, licorice root appears most often as part of combination products, reflecting real-world skincare use. Despite this limitation, outcomes show repeatable trends that support continued research interest.

Key Findings From Human Studies

Clinical studies report improvements in acne-related skin parameters following regular use of licorice-containing formulations. Measured outcomes align with known skin-related mechanisms of licorice root compounds.

Frequently reported findings include:

• Reduced inflammatory and non-inflammatory lesion counts
• Decreased visible redness and irritation
• Lower sebum production in acne-prone skin
• Improved overall skin appearance and comfort

These results are most pronounced after several weeks of consistent topical use.

Supportive Mechanistic and Translational Data

Mechanistic studies strengthen the clinical findings by explaining how licorice root compounds act at the skin level. Laboratory and ex vivo research shows reduced inflammatory signaling and modulation of skin responses associated with acne development. This data supports the biological plausibility of observed clinical outcomes.

Although not all mechanistic studies involve human subjects, they provide context for the effects measured in clinical trials.

Strength of Evidence and Research Gaps

The overall strength of evidence is moderate, with clear positive trends but limited standalone licorice trials. Many studies rely on small populations or combined formulations, which restricts definitive conclusions about licorice root alone.

Identified gaps include:

• Lack of large-scale, placebo-controlled trials
• Limited long-term safety and efficacy data
• Inconsistent extract standardization

Clinical Relevance

Current clinical studies position licorice root as a supportive ingredient for acne and skincare rather than a primary treatment. Its role appears most relevant within broader skincare strategies.

Clinical studies of licorice root for acne and skincare show consistent improvements in lesions, inflammation, and skin balance, supported by mechanistic data, but further well-controlled trials are needed to confirm standalone efficacy.