Many brands consist of an unpurified extract of Japanese knotweed ("Polygonum cuspidatum"); these contain about 50 percent resveratrol by weight, as well as emodin, which, while considered safe in moderate quantities, can have a laxative effect in high amounts.
Many brands consist of an unpurified extract of Japanese knotweed ("Polygonum cuspidatum"), an introduced species in many countries. These contain about 50 percent resveratrol by weight, as well as emodin, which, while considered safe in moderate quantities, can have a laxative effect in high amounts.