https://sinclair.hms.harvard.edu/people/david-sinclair
Who considers him a quack? Why should I believe them?
A slew of retracted papers from his mentor's lab, and image duplications/fabricated western blots from David's lab:
https://forbetterscience.com/2020/05/14/never-ageing-anti-ag...
https://forbetterscience.com/2023/04/17/the-original-sins-of...
Several blog posts on the resveratrol controversy by Derek Lowe (required reading in pharma/biotech):
https://www.science.org/content/blog-post/resveratrol-srt501...
https://www.science.org/content/blog-post/does-resveratrol-r...
https://www.science.org/content/blog-post/resveratrol-humans...
https://www.science.org/content/blog-post/latest-sirtuin-con...
Also anecdotal, but I personally know several PIs who worked on sirtuins during their PhDs and they all say that David is full of shit.
Dr. Jeffrey Flier: https://twitter.com/jflier/status/1495909501211447305?s=21
Dr. Charles Brenner: https://twitter.com/CharlesMBrenner/status/14966040557993615...
Dr. Brad Stanfield: https://www.youtube.com/watch?v=JAFnD27ffqE