Effects and Benefits of Licorice Extract on Skin
Licorice is a plant with significant medicinal value, utilized in both Western and traditional Chinese medicine. In Western medicine, it has been used since ancient Greece as an expectorant, cough suppressant, and sweetener. Ancient Chinese texts, such as the "Shen Nong Ben Cao Jing," describe licorice as a remedy for strengthening muscles and bones, boosting stamina, and treating wounds, classifying it as a top-tier herb and calling it the "king of herbs."
In traditional Chinese medicine, licorice is associated with the heart, lungs, spleen, and stomach. It is known for its benefits in boosting energy, clearing heat and toxins, relieving cough and phlegm, easing pain, and harmonizing other herbs. It’s typically used to address conditions like spleen and stomach deficiency, fatigue, palpitations, cough with excessive phlegm, abdominal and limb cramps, abscesses, and to mitigate the toxicity of other medications. The recommended dosage is 1.5 to 9 grams.
Research indicates that licorice can inhibit monoamine oxidase, block the enzyme responsible for diabetes, relieve spasms and pain, combat viral hepatitis, treat osteoporosis, and has anti-parasitic, anti-cancer, and anti-HIV properties.
Its benefits for the skin are primarily in skin brightening and sun protection.
Licorice extract’s skin-brightening effect mainly works by inhibiting the activity of tyrosinase and TRP-2 (a pigment-transforming enzyme), preventing the polymerization of 5,6-dihydroxyindole (DHI) to block melanin production and achieve a whitening effect.
The sunscreen properties of licorice extract come from its flavonoid compounds. Due to the conjugated molecular structure of these compounds, they absorb both ultraviolet and visible light effectively. When these molecules absorb high-energy UV rays, they transition from a ground state to an activated state and then return to the ground state, releasing harmless low-energy rays. Compared to synthetic sunscreens, licorice extract does not require added antioxidants in formulations, is less likely to irritate the skin, and has strong stability in absorption.
