Answer:

Japanese knotweed, an herb which you may see listed as Polygonum cuspidatum or Fallopia japonica on your supplement label, is a common source of resveratrol. In fact, every resveratrol product we tested in our review contained Japanese knotweed, although some contained additional sources. This may be because red wine extract, red grape skin extract and other sources of resveratrol tend to be more expensive and contain smaller amounts of resveratrol than Japanese knotweed. For more about sources of resveratrol, what to look for on a resveratrol supplement label, plus our tests of products, see the Resveratrol Supplements Review >>

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6 Comments

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ConsumerLab.com
October 10, 2014

To address some of your comments and questions, we've added more information about Japanese knotweed to the Resveratrol Review: https://www.consumerlab.com/reviews/%20/Resveratrol_Red_Wine/#whatitis

Thomas205
October 6, 2014

Hopefully Japanese knotweed is cultivated in countries other than Japan.

Barb204
October 6, 2014

I have Japanese Knotweed growing on my property in Oregon. I wonder if it is edible off the bush.

Joanna203
October 6, 2014

I think it's important to add that Japanese knotweed is an invasive species in North America! Wikipedia says: "It is listed by the World Conservation Union as one of the world's worst invasive species." and "The invasive root system and strong growth can damage concrete foundations, buildings, flood defences, roads, paving, retaining walls and architectural sites. It can also reduce the capacity of channels in flood defences to carry water". I'll stick with red wine too!

Marie197
October 6, 2014

Actually drinking red wine (small amounts of course) is a lot more fun.

Nancy201
October 6, 2014

...and taste better and less processed. Grapes, unpeeled of course, and washed, are probably the best.

kendra226
October 12, 2014

Hmm, how is red wine, especially commercial wine, less processed than an herb that is simply dried and powdered?

Monique195
October 5, 2014

I had no idea that Japanese Knotweed contains Resesvatrol : but with the environment to be desired in Japan after what happened 2 years ago. I am not ready to use Japanese herbs…..

Timothy200
October 6, 2014

Japanese Knotweed is a dangerous invasive plant in riparian areas in the western U.S.

Julie213
October 8, 2014

Although I too am concerned about Japanese Knotweed, apparently we can grow it here. Remember Dandelines are invasive too, but if we ate them, we would be glad they were around. They are so good for your health....mint is invassive but it is good for your health.
Do you think everything good for your health is invasive so we have enough....I don't know but it would explain why it is so virile!

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