There is a very simple measure for any new potential therapy for enhanced longevity: is it either (a) doing at least as well as calorie restriction in mice when it comes to health and longevity, or (b) achieving important results that calorie restriction cannot show in mice - such as outright rejuvenation. The popular supplement resveratrol fails miserably to achieve significant results in either of these goals after more than five years of experimentation and hundreds of millions of dollars in research funding. This means that it is a dead end, or so close to one as makes no real difference. The only value gained lies in incremental improvements in the understanding of metabolism - which could have been achieved while studying more effective paths to the same end goal.
Age is the most important risk factor for diseases affecting the Western world, and slowing age-related degeneration would greatly improve the quality of human life. In rodents, caloric restriction (CR) extends lifespan by up to 50%. However, attempts to mimic the effects of CR pharmacologically have been limited by our poor understanding of the mechanisms involved. SIRT1 is proposed to mediate key aspects of CR, and small molecule activators may therefore act as CR mimetics.
The polyphenol resveratrol activates SIRT1 in an in vitro assay, and produces changes that resemble CR in vivo, including improvements in insulin sensitivity, endurance, and overall survival in obese mice. However, resveratrol has numerous other targets that could contribute to its health benefits. Moreover, unlike bona fide CR, resveratrol has not been shown to extend lifespan in lean mice.
Whenever a new supplement, drug, or something else you can put in your mouth is announced to possibly affect longevity, there follows a breathless wave of hype and money-making. Go search for "resveratrol" to see the present pointless wasteland of thoughtless buyers and manipulative sellers. You'd think that no-one has a memory of longer than a year: every time this happens exactly the same way, and in the end it all comes to nothing.
Silver bullets don't exist, and the future of longevity science will not be found in paths that fail to show immediate, exciting benefit in mouse studies. When there are multiple ways to extend mouse life span by 50%, why would anyone be worked up about about something that fails to move the needle at all? It's way past time to move on from the resveratrols of the world and focus on research and development that can have a positive effect on the future of human longevity.