Ingredient dossier Nº 030 / The verified record
Licorice Root (Glycyrrhiza Glabra)
GLYCYRRHIZA GLABRA (LICORICE) ROOT EXTRACT
Effective concentration, the pH it needs, how the derivatives compare, stability in the bottle, and the open questions — every scientific claim on this page links to its source.
- antioxidant
- brightening (tyrosinase / melanin inhibition, via glabridin)
- soothing / anti-inflammatory (via licochalcone A)
- skin conditioning
Editorial verdict / Social intelligence
A gentle dual-purpose botanical — a supportive brightener (glabridin) and a genuinely soothing anti-redness ingredient (licochalcone A) — just not a hydroquinone-strength dark-spot eraser. 1
- Beauty benefit
- Licorice root is a gentle two-in-one: glabridin (from Glycyrrhiza glabra) gives it a mild skin-brightening reputation, while licochalcone A and glycyrrhizin make it one of the better-evidenced soothing, anti-redness botanicals — a quiet favourite in sensitive-skin and brightening formulas alike.
- Does it work
- Yes, but it helps to split the two jobs. The brightening side (glabridin) is real in mechanism — it's a tyrosinase inhibitor that lowers melanin via the MITF pathway — but most of that evidence is cell-culture and zebrafish, so it's gradual and supportive, not hydroquinone-level spot fading. The soothing side is actually the better-evidenced one: in human vehicle-controlled trials, topical licochalcone A significantly reduced redness and irritation. So licorice genuinely earns both reputations, with one honest caveat: they come from different molecules (and often different licorice species), and a label that just says 'licorice extract' rarely tells you which — or how much — you're getting. Vegan. See the science below →
Consensus strength
ModerateLicorice is well-liked for gentle brightening and for calming redness, and both have real support — glabridin inhibits tyrosinase/MITF (brightening) and licochalcone A has human vehicle-controlled trials for reducing erythema (soothing). The honest limits: the brightening evidence is largely in-vitro and gradual rather than hydroquinone-level, the two effects come from different compounds and often different species, and the active content is rarely disclosed.
01 / What it does
What it does
Licorice root is one of skincare's favourite 'gentle brighteners', but the honest version of the story is that 'licorice' is really two different stars, often from two different plant species. The first is glabridin, an isoflavan concentrated in Glycyrrhiza glabra (European licorice). Glabridin is a tyrosinase inhibitor: it slows the rate-limiting enzyme of melanin production, which is the mechanism behind licorice's 'skin-whitening' reputation, and newer work ties G. glabra's depigmenting effect to the CRTC1/MITF pigmentation pathway. The second star is licochalcone A, a chalcone from Glycyrrhiza inflata (and G. uralensis) — and this is the molecule with actual human, vehicle-controlled clinical trials, where topical licochalcone A significantly reduced redness in shave- and UV-induced irritation models. So licorice genuinely earns two reputations: a mild brightener (glabridin) and a soothing anti-redness ingredient (licochalcone A). The catch is that they're different compounds from different species, the brightening evidence is largely cell-culture and zebrafish rather than facial pigmentation trials, and a label that just says 'licorice extract' rarely tells you which actives — or how much — you're getting.
- Study Glabridin, an isoflavan isolated from the root of Glycyrrhiza glabra, reversibly and noncompetitively inhibits tyrosinase — the rate-limiting enzyme of melanin production — with an IC50 of 0.43 micromol/L, the mechanistic basis of licorice's skin-brightening reputation. 1
- Study An 80% ethanol extract of Glycyrrhiza glabra was the most potent inhibitor of mushroom tyrosinase, and its depigmenting (skin-whitening) activity, attributed largely to glabridin, was linked to inhibition of the CRTC1/MITF pigmentation pathway. 2
- Study In prospective randomized vehicle-controlled clinical trials, topical licochalcone A (a phenolic constituent of Glycyrrhiza inflata) caused a highly significant reduction in erythema versus vehicle in both post-shave and UV-induced redness models, demonstrating genuine anti-inflammatory/anti-irritant activity. 3
- Review Glabridin, a prenylated isoflavonoid of G. glabra roots, is associated with antioxidant, anti-inflammatory and skin-whitening activities and is a key chemical and biological marker of standardized licorice extracts used in cosmetics. 4
02 / Effective concentration
What percentage actually works
Effective range
No standardized cosmetic concentration — and the marker compound
There's no validated 'use this %' for licorice, because the active you care about depends on the species and extract: glabridin (brightening) comes mainly from G. glabra, licochalcone A (anti-redness) from G. inflata / G. uralensis, and the glycyrrhizin-derived soothers (e.g. dipotassium glycyrrhizate) are different again. A label reading 'licorice root extract' tells you neither which marker compound is present nor how much, so potency isn't comparable between products.
Glabridin is described as the key chemical and biological marker of standardized G. glabra extracts, which is exactly why standardisation matters — two licorice extracts can differ enormously in glabridin (or licochalcone A) content depending on species, plant part, and extraction. Processing changes it further: heat treatment and fermentation measurably alter licorice's antioxidant and anti-melanogenic activity. The meaningful question for a 'licorice' product is which standardized active it delivers, not the headline extract percentage.
- Review Glabridin is identified as a key chemical and biological marker of Glycyrrhiza glabra, and standardized licorice extracts (defined by their glabridin content) are what carry consistent cosmetic activity. 4
- Study Heat treatment (130 C) measurably changed the antioxidant and anti-melanogenic activity of licorice extract, showing that processing — not just the headline 'licorice' label — determines the finished extract's potency. 5
One honest caveat Glabridin's brightening evidence is largely in-vitro (tyrosinase kinetics, melanoma-cell and zebrafish models, MITF pathway); controlled human facial-pigmentation trials of licorice/glabridin are limited.
03 / pH requirement
The pH it needs
Target pH
No pH gate — it works by enzyme inhibition and antioxidant chemistry, not as a pH-activated acid
Licorice's actives are not pH-dependent acids. Glabridin brightens by directly inhibiting the tyrosinase enzyme (a noncompetitive, reversible interaction) and by acting on the MITF pigmentation pathway, while licochalcone A and the licorice flavonoids work through anti-inflammatory and antioxidant mechanisms. None of these require an acidic pH to function, so the formulation variables that matter are the species/marker compound used and protecting these flavonoids from oxidation — not pH.
- Study Glabridin inhibits tyrosinase noncompetitively and reversibly through a direct enzyme-binding mechanism, an antioxidant/enzyme-inhibition action rather than a pH-activated one. 1
04 / Derivative ladder
How the derivatives compare
Every derivative trades a measure of proven activity for stability or gentleness. Skin conversion is the question that matters — a more stable molecule only helps if your skin can turn it back into the active form.
Licorice Root (Glycyrrhiza Glabra) has no meaningfully used cosmetic derivative ladder — it is formulated as the free acid itself. That is the form the research below was run on, so there is no conversion step to discount.
05 / Stability & storage
Stability in the bottle
Licorice's actives are flavonoids and isoflavonoids (glabridin, licochalcone A) and, like most antioxidants, they're sensitive to light and oxidation, so well-designed, opaque or airless packaging helps preserve them. Bioactivity is also markedly shaped by processing: heat treatment of licorice extract changed its antioxidant and anti-melanogenic activity, and yeast fermentation altered the bioactive components of a licorice water extract and increased its polyphenol and flavonoid content and whitening activity. In other words, the same starting plant can yield very different finished extracts depending on species, plant part, and how it's processed — consistency comes from standardisation to a marker compound.
- Study Heat treatment at 130 C raised the radical-scavenging (antioxidant) activity of licorice extract, demonstrating that thermal processing changes the extract's measurable bioactivity. 5
- Study Yeast (Issatchenkia orientalis) fermentation altered licorice's bioactive components, increasing polyphenol and flavonoid content and producing stronger inhibition of melanin production than the non-fermented extract, so processing changes which actives — and how much activity — a licorice extract delivers. 6
In practice Buy it in an opaque, airless, or amber container, store it cool and out of the light, and treat a colour shift toward orange or brown as the signal to replace it — the molecule is telling you it has already oxidised.
06 / How to use it
How to actually use Licorice Root (Glycyrrhiza Glabra)
- When
- AM or PM — Serum/essence step after cleansing.
- Pairs well with
- niacinamide, vitamin C, alpha-arbutin, tranexamic acid.
- Apply apart from
- Nothing major — it layers comfortably with most actives.
- What to look for
- Standardized for glabridin (brightening) or licochalcone A (redness).
- Heads-up
- Gentle and vegan; gradual — works best inside a brightening or anti-redness routine, not alone.
Practical guidance for routine placement — not a substitute for a dermatologist’s advice for your skin.
07 / The database
Licorice Root (Glycyrrhiza Glabra): measured product rankings coming soon
Ranked by $ per gram of active — what the working ingredient actually costs you, not the sticker price. Rows we have reviewed in full link through; the rest are data points from the same crawl.
Buy ACWELL on Amazon $17.64 Top-ranked pick · affiliate link
No measured products yet — this active's price-per-gram rankings will appear here as products are added.
In the meantime, see how to use Licorice Root (Glycyrrhiza Glabra) and what to look for on a label , or compare it with every other brightening active.
Contains it, but doesn't disclose a percentage: ACWELL ACWELL Licorice pH Balancing Advance Serum ; ACWELL ACWELL Licorice pH 5.5 Balancing Cleansing Toner
08 / Safety
Is it safe?
Cosmetic Ingredient Review status
Licorice-root ingredients have a long history of use in foods and cosmetics and are generally well tolerated; consult the cosmetic-ingredient literature for assessments of specific licorice fractions and derivatives.
Topically, licorice's reputation is gentle-and-soothing, and that part is genuinely well supported: licochalcone A significantly reduced redness in vehicle-controlled human trials, and a licochalcone-A-containing moisturizer improved skin tolerability when added to an irritating acne retinoid regimen. That anti-inflammatory character is why licorice (and its derivative dipotassium glycyrrhizate) shows up in sensitive-skin and post-procedure formulas. Licorice extracts are plant-derived and therefore vegan-friendly. As with any botanical, individual sensitivity is possible, so patch-test if you're reactive. One clarification worth making: the blood-pressure / potassium concern people associate with licorice comes from EATING glycyrrhizin-rich licorice (a systemic effect), not from topical licorice cosmetics applied to the skin — the two should not be conflated.
- Study Topical licochalcone A produced a highly significant, vehicle-controlled reduction in skin erythema in human post-shave and UV-irritation models, supporting licorice's soothing, anti-irritant positioning. 3
- Study In a double-blind randomized controlled trial, a moisturizer containing licochalcone A, l-carnitine and 1,2-decanediol improved tolerability when used alongside adapalene gel for acne, consistent with licorice's gentle, irritation-relieving role. 7
09 / The limits of the evidence
What we don't know yet
Most of what you read about this ingredient is stated with more certainty than the evidence earns. Here is exactly where the record thins out — so you can weigh the claims above for yourself.
- 'Licorice' is really two different stars from different species: glabridin (brightening, mainly Glycyrrhiza glabra) and licochalcone A (anti-redness, Glycyrrhiza inflata / uralensis) — a product's species and marker compound determine what it actually does.
- Glabridin's brightening evidence is largely in-vitro (tyrosinase kinetics, melanoma-cell and zebrafish models, MITF pathway); controlled human facial-pigmentation trials of licorice/glabridin are limited.
- The strongest human (RCT) evidence is for licochalcone A reducing redness and irritation, not for glabridin fading pigment — the soothing and brightening claims rest on different molecules and shouldn't be transferred to one another.
- Glabridin and licochalcone A content varies widely by species, extract solvent and processing (heat treatment and fermentation change the activity), and labels rarely disclose it, so potency isn't comparable between products.
- Brightening is gradual and supportive — best paired with niacinamide, vitamin C, tranexamic acid or alpha-arbutin — not hydroquinone-level depigmentation.
- Clarification, not a flaw: the blood-pressure / glycyrrhizin concern relates to DIETARY licorice (a systemic effect), not to topical licorice cosmetics — the two are sometimes conflated and shouldn't be.
10 / What people say
What formulators and users say
What works
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Glabridin, an isoflavan, isolated from the root of Glycyrrhiza glabra Linn, has exhibited several pharmacological activities, including excellent inhibitory effects on tyrosinase. Study
- Common Genuinely soothing and anti-redness — and this is the side with real human trials (licochalcone A) 37
Topical LicA causes a highly significant reduction in erythema relative to the vehicle control in both the shave- and UV-induced erythema tests, demonstrating the anti-irritative properties of LicA. Study
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Glabridin, a prenylated isoflavonoid of G. glabra L. roots (European licorice, Fabaceae), has been associated with a wide range of biological properties such as antioxidant, anti-inflammatory, anti-atherogenic, regulation of energy metabolism, estrogenic, neuroprotective, anti-osteoporotic, and skin-whitening. review
What to know
- Common The brightening is gradual and mostly lab-based — not hydroquinone-level, and the strong human trials are for redness, not pigment 16
The results indicate that glabridin reversibly inhibits tyrosinase in a noncompetitive manner through a multiphase kinetic process with the IC50 of 0.43µmol/L. Study
- Common 'Licorice' content and species vary hugely and are rarely disclosed — processing changes the activity too 5
We verified the effect of heat treatment on the bioactivity of licorice by comparing antioxidant and anti-melanogenic activities of licorice extract before and after heating (130 °C). Study
What you'd only know from the reviews
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'Licorice' is really two different stars from two different species. Glabridin — the brightening isoflavan — comes mainly from Glycyrrhiza glabra (European licorice). Licochalcone A — the anti-redness chalcone with the human trials — comes from Glycyrrhiza inflata and G. uralensis. They're different molecules doing different jobs, so a product labelled simply 'licorice extract' could lean either way, and the two reputations shouldn't be transferred to each other. 48
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One common worry to set aside: the blood-pressure concern people associate with licorice comes from eating glycyrrhizin-rich licorice (a systemic effect), not from topical licorice cosmetics, which are applied to the skin's surface. Topically, licorice's character is the opposite — calming and anti-inflammatory — and because it's plant-derived, it's vegan-friendly. 3
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11 / Questions
Frequently asked
- What is licorice root extract and what does it actually do in skincare?
- It's an extract of Glycyrrhiza (licorice) root, and it earns two different reputations from two different actives. Glabridin (mainly from G. glabra) is a tyrosinase inhibitor — that's the 'brightening' side. Licochalcone A (from G. inflata/uralensis) is anti-inflammatory and is the molecule with real human trials showing reduced redness — that's the 'soothing/calming' side. So licorice is a gentle brightener and a redness-calmer, but those two jobs come from two different compounds. 14
- Does licorice fade dark spots or brighten skin?
- Mildly and gradually. Glabridin inhibits tyrosinase and licorice extracts lower melanin via the MITF pathway in cell and zebrafish studies, which is a real brightening mechanism — but it's mostly lab-level evidence, not hydroquinone-strength depigmentation, and human facial pigmentation trials of glabridin are limited. Think of licorice as a supportive brightener that pairs well with niacinamide, vitamin C, tranexamic acid or alpha-arbutin, rather than a standalone dark-spot eraser. 12
- Is licorice good for redness and sensitive skin?
- Yes, and this is arguably its best-evidenced benefit — but it comes from licochalcone A, not glabridin. In vehicle-controlled human trials, topical licochalcone A significantly reduced erythema in shave- and UV-irritation models, and a licochalcone-A moisturizer improved tolerability of an acne retinoid. That's why licorice appears in so many sensitive-skin and anti-redness products. Just note it's a different molecule (and often a different licorice species) from the brightening glabridin. 37
- Are all licorice extracts the same?
- No — and the difference is bigger than with most botanicals. The brightening active glabridin comes mainly from Glycyrrhiza glabra, while the anti-redness active licochalcone A comes from G. inflata and G. uralensis. On top of the species difference, processing matters: heat treatment and fermentation measurably change a licorice extract's antioxidant and anti-melanogenic activity. Since labels rarely disclose the species or the glabridin/licochalcone content, two 'licorice extract' products can do quite different things. 46
- Is topical licorice safe, and is it vegan?
- It's gentle and well tolerated — licorice has a long history of use and its licochalcone A is actively soothing, reducing redness and irritation in human studies, which is why it's common in sensitive-skin lines. It's plant-derived, so it's vegan-friendly. Patch-test if you're very reactive, as with any botanical. And to clear up a common worry: the blood-pressure concern linked to licorice is about EATING glycyrrhizin-rich licorice (a systemic effect), not about topical licorice skincare — don't conflate the two. 38
12 / References
Sources
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