Ingredient Spotlight: Licorice Root Extract
The Glycyrrhiza species, commonly known as licorice, has been used as a topical and systemic herbal medicine for approximately 4,000 years. It presides as one of the oldest and most popular herb in Traditional Chinese Medicine, and has been used around the world for its therapeutic value. The FDA granted Licorice root with the GRAS (Generally Regarded as Safe) status back in 1983. Licorice root has a broad range of biological activity and medical indications include asthma, sore throat, cough, lung disorders, gastric ulcers, various forms of inflammation, and more.
There are two main Glycyrrhiza species used today. First is Glycyrrhiza glabra, which is found growing in the Mediterranean Sea, Middle East, and Russia. Second is Glycyrrhiza inflata, which is the traditional Chinese licorice root. These two species have different chemical constituents that give them therapeutic value.
Both species contain the organic chemical Glycyrrhizin, which is a water-soluble saponin. This is the chemical that gives licorice its sweet taste and has various pharmacological benefits. Both species also contain various polyphenols which act as antioxidants. G. glabra contains the hydrophobic component Glabridin. “Studies investigating the inhibitory effects of glabridin on melanogenesis and inflammation have shown that it inhibits tyrosinase activity of melanocytes.”1 This component is considered a safe skin lightening agent effective in cosmetics for hyperpigmented individuals. G. Inflata contains Licochalcones, in particular Lipochalcone A which is considered the primary active ingredient of this licorice species due to its therapeutic value which includes antioxidant, anti-irritancy, anti-inflammatory, and antibacterial to name a few.2
Topically, Licorice root extract has many values in aiding skin health. It is an optimal ingredient choice for those who have sensitive and pigmented skin due to its anti-inflammatory and skin lightening abilities. It has also been effective in treating atopic dermatitis (eczema), psoriasis, sensitive skin, rosacea, and melasma. Licorice extract, specifically from G. glabra, was effective in treating atopic dermatitis with topical application of a gel with 2% Licorice extract. The study showed the treatment group had a great reduction in erythema, edema, and itching as compared to the control group. The study concluded that licorice root extract was an effective therapy to improve the skin and lives of those suffering with eczema.4 G. glabra was also shown to be effective in the inhibition of p.acnes bacteria.2 This therapeutic value, along with its anti-inflammatory effects indicates Licorice root extract for clients suffering with acne.
Although research is limited, there is good evidence supporting licorice root to be wound healing. A study done on wounded rats concluded that Licorice extract was beneficial to skin healing on several accounts. “Licorice Extract caused a significant increase in the number of fibroblasts and capillary buds, collagen contents and tensile strength of the wounds. The wound surface area in the treatment group was also significantly less than the control group.” 3 The study indicated that licorice root enhanced the production of collagen and increased the re-epithelization rate of the wound. These findings show promising results for licorice roots ability to enhance wound healing in humans, which can also be relevant in preventing PIH in acne lesions.
Overall, licorice root extract is a safe cosmetic ingredient that has stood up to the test of time. It is anti-inflammatory, antibacterial, skin lightening, wound healing, antioxidant, and anti-irritating. Indications for its use in cosmetics would be atopic dermatitis (eczema), rosacea, hyperpigmentation, psoriasis, sensitive or sensitized skin, skin with impaired barrier function, and inflamed acne lesions.
Halder, R. M., and G. M. Richards. "Topical agents used in the management of hyperpigmentation." Skin Therapy Lett 9, no. 6 (2004): 1-3.
Baumann, Leslie S. Cosmeceuticals and cosmetic ingredients. McGraw Hill Professional, 2014.
Oloumi, Mohammad Mahdi, Amin Derakhshanfar, and A. Nikpour. "Healing potential of liquorice root extract on dermal wounds in rats." (2007): 147-154.
Saeedi, Muadhamm, K. Morteza‐Semnani, and M‐R. Ghoreishi. "The treatment of atopic dermatitis with licorice gel." Journal of Dermatological Treatment 14, no. 3 (2003): 153-157.