Joseph Baur earned his Ph.D. from the University of Texas Southwestern Medical Center in Dallas, Texas, where he studied mechanisms that limit the lifespan of cultured human cells under Drs. Jerry Shay and Woody Wright. He then moved to Harvard Medical School where he trained as a postdoctoral fellow with Dr. David Sinclair. There he developed a strong interest in the regulation of aging and metabolism by sirtuins, a conserved class of enzymes that require nicotinamide adenine dinucleotide (NAD) as a co-substrate. His lab currently studies metabolic and signaling pathways by which nutrient intake can influence longevity, with a particular emphasis on NAD and mTOR.