Polygonum cuspidatum extract also known as giant knotweed is an east asian species belonging to the polygonaceae family. The documented usage in traditional Chinese medicines dates back to the first century BC.

Polygonum cuspidatum root extract is a plant whose root is a good source of the potent polyphenolic antioxidant trans-resveratrol, which is considered the most bioavailable form of resveratrol，used to reduce platelet aggregation, the prevention, treatment of atherosclerosis and disease of heart head blood-vessel chemoprophylaxis agent.

Also known as Japanese knotweed, Mexican bamboo, and in Traditional Chinese Medicine as Hu Zhang, this plant not only helps thwart free radicals before they can damage skin, it also reduces signs of irritation.

Research has also shown this plant extract can inhibit the formation of advanced glycation end-products, or AGEs. These are collagen-damaging proteins and fats that form in skin as a reaction from exposure to sugars. Left unchecked, AGEs can contribute to wrinkles and loss of firmness.

Trans-resveratrol has been shown to fade hyperpigmentation when used in amounts of 1% or more; lower levels of Polygonum cuspidatum root in skin care remain viable for antioxidant, soothing, and other benefits.