Houttuynia cordata, sometimes called fish mint, is a plant long used in traditional East Asian medicine, and its extract is rich in flavonoids like quercetin and quercitrin.
In vitro studies show it suppresses production of inflammatory signaling molecules and carries genuine antioxidant activity, and a fermented version of the extract has been shown to protect human keratinocytes from UVA and oxidative stress related damage. It also has documented antibacterial activity, which alongside its calming profile supports its popularity in reactive and blemish prone skin formulas.
Nearly all of the available evidence is cell culture or animal based, so specific claims like pore reducing or soothing effects made for finished products are largely extrapolated from that laboratory research.
Houttuynia Cordata Extract References
Anti inflammatory effects of a Houttuynia cordata supercritical extract, 2010
Protective Effects of Fermented Houttuynia cordata Against UVA and H2O2 Induced Oxidative Stress in Human Skin Keratinocytes, 2022
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