Licorice Extract: Unlocking The Scientific Breakthrough Of Oral “Super-Photon” Licochalcone A For Whitening

"Fair skin conceals a hundred flaws; dark skin ruins everything."

As one of the core global markets for oral beauty products, China's market size is expected to reach 25.57 billion RMB in 2025, advancing toward becoming the world's largest market with a 3.8% compound annual growth rate.
Within China's oral beauty segment, the whitening category is experiencing explosive growth. For example, on JD.com in the first quarter of 2025 (Figure 1), over 3,500 new SKUs were launched in the whitening segment-accounting for about 90% of all new oral beauty products during the same period, far exceeding other sub-categories such as anti-aging, hydration, and anti-hair-loss [1].

Severe Homogenization of Whitening Ingredients-New Actives Are Urgently Needed

The mainstream oral whitening ingredients currently on the market include glutathione, ergothioneine, and white tomato extract. The first two primarily focus their claims on antioxidation and free-radical scavenging, while the latter highlights its photoprotective benefits (Table 1).

However, brands of all sizes are facing concept fatigue. Whitening products are becoming increasingly similar in terms of ingredient selection, leading consumers to lose interest in these repetitive value propositions. The market is in urgent need of new oral whitening actives to inject fresh momentum into the stagnating oral beauty category.

The answer to this demand may lie in the cosmetics sector.

With the rise of the "cosmetics–food homology" trend, the skincare sector has generated many popular ingredient concepts for the oral beauty category. Ergothioneine originated from Helena Rubinstein's iconic Black Bandage cream (Figure 2), which Later Lift converted into its "Ice Crystal Skin" oral product (Figure 3). The concept of astaxanthin came from PROYA's Double Anti line (Figure 4), followed by Me Today's Glow Shot (Figure 5).

The next potential star ingredient, glabridin, stems from Guyu's Aurora Licorice series (Figure 6). This whitening line, centered on glabridin, helped Guyu achieve 5 billion RMB in GMV. As China's leading skincare brand built around glabridin, Guyu has shown explosive growth far surpassing domestic brands such as PROYA and Kans.

However, in the domestic oral beauty sector, glabridin remains largely untapped-creating a significant new opportunity for oral beauty brands.

Figures 2 & 3: Helena Rubinstein Black Bandage and Later Lift Ice Crystal Skin (containing ergothioneine)

Figures 4 & 5: PROYA Double Anti and Me Today Glow Shot (containing astaxanthin)

Figure 6: Guyu Aurora Licorice Series (formulated with glabridin)

Mechanisms of Licorice in Skin Whitening

Licorice has a long history of both culinary and medicinal use in China and is classified as a dual-use food–medicine ingredient. In the classic traditional Chinese beauty formula "San Bai Gan Cao Tang", licorice is combined with Atractylodes, White Peony, and Poria to target skin concerns such as hyperpigmentation, melasma, roughness, and dryness. Licorice is also included in well-known traditional whitening prescriptions such as "Yu Rong San" and "Yu Nü Tao Hua Fen."

Modern research shows that licorice contains bioactive components such as glycyrrhizin, glycyrrhetinic acid, and glabridin, which positively influence melanocytes exposed to photodamage, oxidative stress, and inflammatory stimuli-reducing the likelihood of excessive melanin production. In addition, licorice can lower melanin levels by inhibiting tyrosinase, the key enzyme involved in melanogenesis.

"Oral Super Photonic" - Glabridin

Multiple species of licorice exist, and three are permitted for use in China: Glycyrrhiza uralensis, Glycyrrhiza inflata, and Glycyrrhiza glabra. Glabridin, a unique bioactive compound found exclusively in Glycyrrhiza glabra, requires several years of growth to accumulate and is naturally present at extremely low levels.
From 1,000 kg of G. glabra plants, only approximately 0.1 kg of glabridin can be extracted-a 1:10,000 extraction ratio that underscores its rarity.

At the same time, glabridin exhibits remarkably potent whitening efficacy, earning its reputation as an "oral super photonic" ingredient. It has already gained significant traction in the skincare sector and is widely adopted by major beauty brands.

A Powerful Tyrosinase Inhibitor**

Beyond its antioxidant and anti-inflammatory properties, glabridin's most exceptional functionality lies in its strong inhibitory effect on tyrosinase. Among all known natural plant-derived actives, it has few rivals, and its inhibitory strength is significantly higher than commonly used tyrosinase inhibitors such as kojic acid and arbutin.

According to published research [2], glabridin acts like a molecular gate-lock, blocking access to the catalytic center of tyrosinase. By preventing tyrosine from entering the active site and undergoing subsequent transformation, glabridin effectively interrupts melanin synthesis at its source.

Figure 8:
A: In the absence of glabridin, tyrosine (dark blue) can enter the catalytic center (light blue) and is gradually converted into melanin.
B: In the presence of glabridin (light green), the entrance to the catalytic center is blocked, preventing tyrosine from entering.

According to the testing data from a third-party institution [4], the tyrosinase inhibitory activity of Licochalcone A and LicoSnow licorice extract is significantly superior to that of similar products. The experiment used the half-maximal inhibitory concentration (IC50) of tyrosinase as the evaluation criterion. This indicator represents the concentration of the raw material required to inhibit 50% of tyrosinase activity. A lower IC50 value indicates that the raw material exhibits significant inhibitory effects at a lower concentration, demonstrating stronger tyrosinase inhibition.

To ensure fairness, the experiment was divided into two comparison groups:

Group 1: High-purity raw materials (purity >98%), including Licochalcone A, glutathione, ergothioneine, and kojic acid (a positive control for tyrosinase inhibition), a total of four materials.

Group 2: Plant extracts, including LicoSnow licorice extract (containing 4% Licochalcone A), melon concentrate powder (containing SOD), and white tomato concentrate powder (containing dihydro-/tetrahydro-lycopene), a total of three materials.

The IC50 values of each raw material are shown in Table 2.

Based on the IC50 values, the comparative tyrosinase inhibitory activity of the two groups is illustrated in Figures 9 and 10. In Group 1, the tyrosinase inhibitory activity of Licochalcone A is 1.4 times that of glutathione, 3 times that of kojic acid, and 141 times that of ergothioneine. In Group 2, the tyrosinase inhibitory activity of LicoSnow licorice extract is 11 times that of melon concentrate powder and 6,930 times that of white tomato concentrate powder.

Clinical Validation of Oral Whitening with Licorice

Although the whitening effect of Licochalcone A has long been recognized by the scientific community and is increasingly valued in the skincare industry, no published human clinical studies on its oral whitening effect have been reported. LicoSnow licorice extract (containing 4% Licochalcone A) precisely fills this gap.

Huasheng Ingredients, in collaboration with a well-known third-party testing institution, conducted a 1-month human trial involving 34 participants (women aged 25–50 years) [5]. Participants orally consumed 100 mg of LicoSnow licorice extract per day (containing 4 mg Licochalcone A). Whitening effects were evaluated through instrument-based measurements and questionnaires. The experimental results are as follows:

Reduction in facial pigmentation (16%↓):
After 28 days of consumption, the area of facial pigmentation decreased from 19.87% to 16.65%, a reduction of 16.21% (p = 0.004), showing a significant difference before and after supplementation. A comparison of participants' facial pigmentation is shown in Figure 11.

Figure 11: Changes in facial pigmentation; left: before consumption, right: after consumption

Increase in skin radiance (21%↑):
After 28 days, facial skin radiance increased from 4.0% to 4.84%, a 21.00% improvement (p = 0.014), showing a significant difference before and after supplementation. A comparison of participants' skin radiance is shown in Figure 12.

Figure 12: Changes in facial skin radiance; left: before consumption, right: after consumption

Reduction in post-UV pigmentation (15%↓):
Artificial UV irradiation was applied to the participants' backs to create tanning areas. Two days after irradiation, pigmentation distribution was measured to evaluate post-UV pigmentation. Measurements were taken at the start of supplementation (D-2 irradiation, D0 measurement) and at the end (D28 irradiation, D30 measurement). After 28 days, melanin values in the tanned areas decreased from 99 to 84, a reduction of 15.15% (p < 0.001), showing a significant difference before and after supplementation.

Reduction in skin redness (28%↓):
After 28 days, the redness value (a* value, higher values indicate redder skin) of the back decreased from 10.70 to 7.69, a reduction of 28.13% (p < 0.001), showing a significant difference before and after supplementation.

Overall skin improvement (≈90% of participants agreed):
After 28 days, nearly 90% of participants reported overall skin improvement, such as more even and brighter skin tone, enhanced radiance, and reduced susceptibility to tanning or redness.

Good safety profile:
No adverse reactions were observed during the trial period.

References:
[1] Boguang Research Institute. 2025 China Oral Beauty Market Research Report.
[2] Chen J, Yu X, Huang Y. Inhibitory mechanisms of glabridin on tyrosinase. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 2016 Nov 5;168:111-117.
[3] Test report issued by Shenzhen 863 Testing Center.
[4] Human trial report issued by Huace Testing.