I am in Australia for some reason the links dont work well but I found this one with someone asking a similar question,
Thanks for a wonderful book and forum. I was diagnosed with early stage estrogen positive breast cancer and one of my doctors told me not to take the knotweed because: “As resveratrol exhibits estrogen-like properties and activates transcription by estrogen receptor and androgen receptor that leads to stimulation of cancer cell proliferation, patients with hormone-sensitive cancers should avoid resveratrol. ” However, my integrative lyme doctor said the effect was so minute that she finds it hard to believe that with all its positive effects that I was asked to discontinue taking knotweed. Please, what is your opinion on the above?
The effect is minute but you can substitute stephania instead to make him/her happy. You should not be taking pure resveratrol in any event but knotweed standardized for resveratrol content; such a mix contains a lot of things besides resveratrol.