A resveratrol drug like that could potentially generate billions of dollars in sales for Glaxo. To succeed, the pharmaceutical giant would have to argue successfully that only its prescription formulation of resveratrol -- and not the similar substances sold on the Internet, in health food stores or TV infomercials -- provide real therapeutic benefit. Yet, Glaxo's huge investment in resveratrol drug research is potentially undermined, even jeopardized, by the Sirtris-turned-Glaxo executives who sold them on the idea but then turned around and started selling their own cheap resveratrol over the Internet. Glaxo's Alspach had no further comment. Glaxo's decision to acquire Sirtris for $720 million was a gamble because at that time, Sirtris had very little clinical data to support its theory that resveratrol drugs could extend life or treat and cure disease. In fact, no clinical trial in humans to date has substantiated the anti-aging or disease-modifying claims made about resveratrol In April, Glaxo terminated a clinical trial of its resveratrol drug SRT501 in multiple myeloma after some patients developed kidney damage. Other studies of Glaxo's resveratrol drugs have either been completed or are still enrolling patients. Dipp told Xconomy that her Healthy Lifespan Institute was selling the custom-made resveratrol formulation web site at cost and was not profiting from sales. Dipp was one the first employees at Sirtris and is now senior vice president of Glaxo's Center of Excellence for External Drug Discovery, responsible for helping Glaxo form drug development partnerships with smaller biotech firms. Westphal was the CEO of Sirtris both before and after Glaxo's acquisition. He now runs SR One, Glaxo's internal venture investing unit. Dipp and Westphal are also founding partners of Longwood Founders Fund, a Boston-based venture capital firm in which Glaxo is an investor. -- Reported by Adam Feuerstein in Boston. Follow Adam Feuerstein on Twitter.