Resveratrol is composed of two principal isomers: trans-resveratrol and cis-resveratrol. Only the trans-isomer has been associated with health benefits. The cis isomer actually acts to nullify the effects of trans-resveratrol. Unless the seller states on the label that the product consists entirely of the trans-resveratrol form it is highly likely that it contains either some or all of cis-resveratrol, which is, by an order of magnitude, the less costly form of resveratrol. I have been using the Swanson Ultra - Resveratrol 250 which states only the following:
(Polygonum cuspidatum root extract) 250mg. I would like to ensure I am purchasing the best variety.
This is new information to us. In all our documentation and in all the studies we've read, we've seen no mention or hint that cis-resveratrol inactivates, competes with or nullifies the action of trans-resveratrol. Here's what we do know: The trans is a bit more bioavailable because its open form is more accessible. Also, most all the tests that have been done on various resveratrol products would have shown a null result because there wasn’t any isolated trans-resveratrol used. We would be interested in reading this ebook you cite and comparing it to the published studies on record, as we suspect it's nothing more than a good bit of marketing trying to sell a specific resveratrol product.
(Note: as per industry regulations, we cannot and will not answer medical questions, make treatment or diagnosis recommendations or comment on disease inquiries. Such questions must be answered by your doctor or professional health care provider.)