Polygonum cuspidatum root extract
AKA “Japanese Knotweed”
Extract
Ingredient Facts
Polygonum cuspidatum root extract
AKA: Japanese Knotweed
Extract · Antioxidant · EWG: 4
Plant-Derived
Antioxidant
Soothing
Skin Conditioner
Extract
Clean
Japanese Knotweed root extract is a natural antioxidant that helps protect skin from environmental damage and supports a healthy, radiant complexion.
Family
Polygonaceae (Buckwheat family)
Plant Part
Root
Lifeform
Perennial
Climate
Seasonally dry tropical
CAS #
-
Form
Liquid
See origin →
Functions
Antioxidant
Fights free radicals — the unstable molecules from UV, pollution, and stress that break down collagen and cause premature aging.
Skin Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Soothing
Calms redness, irritation, and inflammation. Your skin's chill pill — great for sensitive, reactive, or post-procedure skin.
Neutralizes Free Radicals
Traditional Use
Used in Traditional Chinese Medicine as Hu Zhang for clearing heat and promoting skin health. Japanese knotweed root has been traditionally valued for its antioxidant properties and skin purification benefits.
Skin Types
●all-skin-types
Best For
Antioxidant
Melanin-Rich Skin
Suitable
Pregnancy & Breastfeeding Safe
Yes
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Verified Feb 2026
Data: Kew POWO · CosIng · EWG · CIR