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.

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.