David Sinclair, Sirtuins, and NAD+

GRADE 3·MIXED(3 of 5)Evidence grade 3 of 5, Mixed. Read how the Atlas grades evidence.

Sinclair's peer-reviewed sirtuin and NAD+ research is well documented, but several of his headline public claims (resveratrol, some reprogramming interpretations) have been directly disputed in the peer-reviewed literature and by named scientific critics, so the entry blends solid primary science with contested claims.

Reference only. Not medical advice.

David Andrew Sinclair (born 1969 in Sydney, Australia) earned a biochemistry degree and a PhD in molecular genetics from the University of New South Wales before joining Leonard Guarente's laboratory at MIT as a postdoctoral researcher in the mid-1990s. There he contributed to research showing that the yeast gene SIR2, a sirtuin, could extend replicative lifespan by reducing the buildup of toxic extrachromosomal ribosomal DNA circles, and that the metabolic cofactor NAD was essential to sirtuin enzymatic activity. In 1999 Sinclair moved to Harvard Medical School, where in 2004 a five million dollar gift from philanthropist Paul Glenn established the Glenn Laboratories for the Biological Mechanisms of Aging, which Sinclair has directed since. His research program focused on the human sirtuin SIRT1 and compounds that might activate it, most prominently resveratrol, a polyphenol found in red wine and grape skins. A 2003 Nature paper and a widely covered 2006 study reported that resveratrol activated SIR2-family enzymes and extended survival in mice fed a high-fat diet. Sinclair co-founded Sirtris Pharmaceuticals in 2004 to commercialize sirtuin activators, and the company was acquired by GlaxoSmithKline in 2008 for 720 million dollars. However, starting around 2005, independent laboratories reported that the fluorescence-based assay used to measure sirtuin activation was flawed, producing an artifact that made resveratrol appear to activate SIR2 directly when it did not, and that resveratrol's benefits in the original studies applied mainly to unhealthy, overfed mice rather than to maximum lifespan in healthy animals. GSK discontinued its sirtuin drug program without an approved therapy by 2013. Sinclair continued to promote NAD+ precursor molecules, particularly NMN, co-founding companies including Metro International Biotech and Life Biosciences, and published the best-selling book Lifespan: Why We Age and Why We Don't Have To in 2019, which brought sirtuin and NAD+ science to a mass audience alongside his own supplement regimen. Biochemist Charles Brenner, a leading NAD+ researcher, has been Sinclair's most prominent scientific critic, publishing papers questioning the sirtuin-activation assay and a public newsletter and social media presence critiquing what he characterizes as overstated claims in Sinclair's book and media appearances. In January 2023, Sinclair published a Cell paper proposing that loss of epigenetic information drives aging and that partial reprogramming with Yamanaka factors could reverse it in mice; researchers James Timmons and Brenner published a formal reply arguing the treatment produced cell death effects that undermined the paper's interpretation. In 2024, a supplement for dogs marketed by Sinclair's company Animal Bioscience with claims of reversing aging, based on undisclosed ingredients, prompted the Wall Street Journal to report a cascade of resignations from the Academy for Health and Lifespan Research, a longevity advocacy group Sinclair had co-founded and led. Sinclair remains an influential and highly cited aging researcher whose sirtuin and NAD+ work helped popularize the modern longevity field, but his career is also a frequently cited case study in the tension between commercial promotion and scientific caution in translational aging research.

David Andrew Sinclair (born 1969 in Sydney, Australia) earned a biochemistry degree and a PhD in molecular genetics from the University of New South Wales before joining Leonard Guarente's.