We use essential cookies (authentication, your saved goals/stack) by default. With your permission we'll also enable privacy-respecting analytics (Vercel Web Analytics, anonymous load-time metrics) and error-replay diagnostics (Sentry — DOM snapshots only when an error fires) so we can fix bugs faster. Learn more about cookies

Glb4.0

Licorice Extract / Glabridin (topical) Research

Mostly mechanism / observationalHigh safety

4 peer-reviewed studies

What the evidence says

Mostly mechanism / observational

Most Licorice Extract / Glabridin (topical) studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.

Most evidence is from mixed-quality randomised trials published 1998–2021 with a typical study size of 56 participants.

Based on 4 studies · 2 RCTs · 76 total participants

Confidence

Low

By outcome

Skin tone & pigmentationGentle brightening of hyperpigmentation/melasma; modest and mostly from small or combination studies (cosmetic, not a health outcome) · 4-12 weeks
Mostly mechanism / observational3 studies
Safety profile
Too few graded studies1 study
Cold sores & HSV
Too few graded studies1 study

Steady research

1 study in the last 5 years

199820092021

1Systematic Review2021

Many in-vivo cutaneous trials of natural ingredients are limited by their study design, including with respect to subject selection and short duration.

Murphy MJ, Dow AA. · J Clin Aesthet Dermatol (2021)

PRISMA systematic review identifying only 7 clinical studies of topical natural depigmenting agents; licorice was among those with supporting efficacy/safety data
Explicitly flags the paucity of robust trials, plus limitations of design, subject selection, and short duration
Concludes further research is needed on long-term efficacy, safety, optimal concentration, and formulation — the key counter-evidence on certainty

2RCTn=20 · very small study2000

Twenty women with a clinical diagnosis of melasma were treated with liquiritin cream on one side of the face and with a vehicle cream on the other side twice daily for 4 weeks.

Amer M, Metwalli M. · Int J Dermatol (2000)

Split-face, vehicle-controlled study (n=20) of liquiritin (a licorice active) cream vs vehicle for idiopathic epidermal melasma, twice daily for 4 weeks
The foundational and most-cited human trial of a licorice active for melasma; pigment intensity and lesion size were tracked with sun protection advised
Very small and short — proof-of-concept for the brightening effect

View source

3RCTn=56 · small study2010

There were no statistic differences between groups in the improvement of melasma. Group A showed less skin adverse events.

Costa A, Moisés TA, Cordero T, Alves CR, Marmirori J. · An Bras Dermatol (2010)

Mono-blind comparative study (n=56) of a Belides + Emblica + Licorice 7% cream vs hydroquinone 2% over 60 days
Depigmentation 78.3% (licorice blend) vs 88.9% (hydroquinone) with no statistically significant difference and fewer adverse events in the botanical group
Licorice was tested only within a multi-ingredient blend — its specific contribution cannot be isolated

View source

4Preclinical1998

The results indicated that glabridin inhibits tyrosinase activity of these cells at concentrations of 0.1 to 1.0 microg/ml and had no detectable effect on their DNA synthesis.

Yokota T, Nishio H, Kubota Y, Mizoguchi M. · Pigment Cell Res (1998)

Foundational mechanism study: glabridin inhibited tyrosinase in cultured melanoma cells (0.1-1.0 µg/ml) without affecting DNA synthesis
Topical 0.5% glabridin inhibited UVB-induced pigmentation and erythema in guinea pig skin
Glabridin also showed anti-inflammatory effects in vitro (inhibiting superoxide and cyclooxygenase) — the dual brightening/soothing rationale (in-vitro/animal only)

View source

View in Research Library

Licorice Extract / Glabridin (topical) Research

Mostly mechanism / observational

Natural Cosmeceutical Ingredients for the Management of Hyperpigmentation in Hispanic and Latino Women.

Topical liquiritin improves melasma.

Association of emblica, licorice and belides as an alternative to hydroquinone in the clinical treatment of melasma.

The inhibitory effect of glabridin from licorice extracts on melanogenesis and inflammation.