Effect of Licorice extract in the treatment of melasma

Melasma is a common acquired cutaneous hyperpigmentation involving sunexposed areas of face predominantly in women: several treatment modalities including topical depigmenting agents are being used in management of this condition with varying results. Hydroquinon is the gold standard in treatment of melasma. Liquorice extract contains natural ingredients such as glabridin and Liquiritin which collectively have multiple effects on skin including skin lightening effect. This study was conducted to compare the clinical efficacy of 4% Hydroquinon and 4% Licorice extract creams in the treatment of melasma.

This clinical trial study was carried out on 38 women who had melasma with bilateral symmetrical hyperpigmentation of malar areas. The hydroquinone and licorice extract creams were applied to the opposite sides of the face once a day at night for 8 weeks. Mmasi scores were separately measured for each side of the face at the base line and every 2 weeks thereafter. The data were analyzed using the SPSS software and Friedman and Wilcoxon signed rank tests.

27 of the patients used the drugs regularly until the end of the study.The mmasi score decreased from 10.59±6.10 to 2.59±2.17 in the treatment (licorice) group and from 0.81±6.34 to 1.63±1.55 in the control (hydroquinone) group after 8 wks. The data showed that a significant decrease in mmasi occurred on the side treated with liquorice after the 8 weeks (P<0.001), while the decrease in mmasi was significantly higher on the side treated with hydroquinone(P=0.002).

Although a significant decrease in mmasi from the baseline occurred on the side treated with 4% liqurice extract cream at the end of the study (P<0.001), 4% hydroquinone cream was significantly more effective in this respect than 4% licorice cream (P=0.002).