Polygonum Cuspidatum Root Extract

An extract from the roots of the Japanese knotweed, a plant from East Asia that has spread around the world as an invasive plant. It contains various antioxidant, anti-inflammatory, and potentially anti-pigment (more tests are necessary) phytochemicals.
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Polygonum Cuspidatum Root Extract


Polygonum cuspidatum root extract is extracted from Japanese knotweed, a plant from East Asia that has spread into the world as an invasive plant.

The extract from the roots (which are thick and strong and able to grow through a concrete panel) is used in skincare for its various antioxidant, anti-inflammatory, and (alleged) anti-pigment properties.

Polygonum cuspidatum root extract contains various phytochemicals, among which the anthraquinones are the most abundant. Anthraquinones are chemically derived from anthracene and act as strong laxatives when ingested. When applied to the skin, however, the preliminary test tube research shows that they inhibit an enzyme called tyrosinase, the main player in the creation of the skin pigment melanin.

This could make Polygonum cuspidatum root extract a potential anti-pigment ingredient, but tests on human volunteers are necessary to see if it really works as expected. Until then, this ingredient can be enjoyed for its proven antioxidant and anti-inflammatory properties.


Zhang, H., Li, C., Kwok, S.-T., Zhang, Q.-W., & Chan, S.-W. (2013). A Review of the Pharmacological Effects of the Dried Root of Polygonum cuspidatum (Hu Zhang) and Its Constituents. Evidence-Based Complementary and Alternative Medicine, 2013, 1–13.