In the book I also introduced what I call the “skeptic’s checklist,” a useful tool for evaluating claims about medical interventions and miracle supplements. The reason this is important is that while data from laboratory studies can reveal interesting properties and lines of research, what happens in a test tube is meaningless unless the effect can be documented in a clinical trial in humans. In order to obtain FDA clearance, for example, clinical trials need to document both safety and objectively measured effectiveness. But since herbal supplements do not fall under the FDA’s purview, there is wide leeway for frequently misleading often outrageous and claims. So without evidence from clinical trials (not the same thing as "clinically tested"), there is no way of knowing whether the product is doing any good or if it is in fact harmful.
There are a few clinical trials underway for resveratrol, and a very small number of published reports. Of the 12 papers that I found on a Medline search using “clinical trial” and “resveratrol,” 3 were not actual clinical trials but studies on blood or tissue in a lab. Another 3 used a wine extract with resveratrol along with the whole family of wine polyphenols, and the rest were what are called pharmacokinetics studies. These types of studies evaluate what is called “bioavailability” or the absorption and distribution of resveratrol after oral ingestion. Without exception they all found low but variable levels, even at high doses.
So it doesn’t appear that resveratrol alone explains the benefits of drinking wine. Synthetic derivatives, up to a thousand times more potent, are being developed so it may turn out that resveratrol opened the door to a new and powerful anti-aging products even if it isn’t the answer alone. For now, a skeptical approach seems the way to go.