To obtain licorice extract, the roots of the plant are dried, peeled and then ground into a powder. The effectiveness of this ingredient on dark spots is due to the presence of glabridine, a powerful depigmenting agent known for its lightening virtues. Find out in detail how it works on the melanogenesis process.
Licorice root extract, an active ingredient for hyperpigmented skin.
- How does Hyperpigmentation appear?
- Melanogenesis, briefly explained
- How does licorice root extract work on skin hyperpigmentation?
How does Hyperpigmentation appear?
Pigmentation spots often impact the uniformity of the complexion. Some people may like them and even want to show them off, while others may want to camouflage them and look for solutions to diminish them.
Hyperpigmentation is defined as a disturbance in the pigmentation process (melanogenesis). Melanin, the pigment that gives the skin its natural color, is overproduced in certain areas, which leads to the appearance of brown, red or pink spots. These spots vary in size and affect all skin tones. They can be classified into three categories:
Melasma or pregnancy mask, linked to hormonal disturbances;
Lentigo or sun spots, due to excessive and repeated sun exposure;
Post-inflammatory hyperpigmentation which results from an overproduction of melanin after an inflammation (wounds, burns, blemishes, acne outbreaks).
The use of certain perfumes and the use of certain medications such as birth control pills can also cause hyperpigmentation. It also happens that the quantity of melanin produced by the body is not sufficient. In this case, it is a case of hypopigmentation which causes the appearance of white spots.
Melanogenesis, briefly explained.
Melanogenesis is the complex biological process that colors the skin, hair and eyes. This function is performed by melanocytes, which synthesize pigments, melanins, and distribute them to the epidermal keratinocytes.
There are two chemically distinct types of melanins in epidermal cells:
Eumelanins, brown to black pigments;
Pheomelanins, red to yellow pigments with a high concentration of sulfur.
How does licorice root extract work on skin hyperpigmentation?
The glabridine contained in more than 95% of the licorice root extract intervenes at several levels to regulate the phenomenon of skin hyperpigmentation:
It limits the activity of tyrosine.
As a reminder, tyrosine is the main enzyme that stimulates the formation of melanin. It is involved at different stages of the melanogenesis process, such as during the very first stage, which consists of the conversion of tyrosine into dopamine. It has been proven that, in equal concentrations, licorice root extract is more effective than kojic acid in inhibiting the action of tyrosine.
It significantly reduces the amount of endothelin-1
released by keratinocytes after UV exposure.
Endothelin-1 is a mediator involved in the pigmentation process. It is produced by keratinocytes following UV exposure. It stimulates the proliferation and migration of melanocytes.
It inhibits the activity of phospholipase A2 (PLA2).
LA2 is an enzyme released by epidermal keratinocytes after UV exposure or during inflammation. It stimulates tyrosine activity and therefore melanogenesis.
Note: At Typology, we use “Glycyrrhiza Glabra Root Extract”. Rich in more than 95% glabridine, it decreases the production of melanin, hence its anti-spot properties and its presence in our serum anti-marks . Nevertheless, from licorice, it is also possible to extract glycyrrhetinic acid (INCI name: Glycyrrhetinic Acid). This compound has contradictory properties compared to “Glycyrrhiza glabra root extract”. Indeed, it is qualified as pro-melanin, i.e. it stimulates melanogenesis at the origin of tanning. It is therefore often found in self-tanning products.
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DELEVPOYE C. & al., Biogenesis of melanosomes - the chessboard of pigmentation. Médecine/Sciences (2011).
SARKAR R. & al. Cosmeceuticals for hyperpigmentation: what is available ? Journal of Cutaneous and Aesthetic Surgery (2013).