Charles Brenner

Charles Brenner holds the inaugural Alfred E. Mann Family Foundation Chair in the Department of Diabetes and Cancer Metabolism at City of Hope's Beckman Research Institute, a position he has held since 2020, after more than a decade as the Roy J. Carver Chair in Biochemistry at the University of Iowa [3]. He also holds a professorship in metabolic regulation at the University of Helsinki [3].

Brenner's foundational scientific contribution is his 2004 discovery of the enzymatic pathway by which nicotinamide riboside (NR) is converted into NAD+ inside cells, work that established NR's activity as a vitamin precursor of NAD+ and underpins the entire commercial NR supplement category [1]. Since 2017 Brenner has served as Chief Scientific Advisor to Niagen Bioscience, the company formerly known as ChromaDex, which sells NR under the brand names Niagen and TruNiagen, a direct and disclosed commercial relationship tied to the same molecule he discovered the mechanism for [1].

Brenner is simultaneously one of the more prominent scientific critics of David Sinclair's public claims about NAD+ precursors and longevity. He authored a peer-reviewed critical review, published in the journal Nutrients, that scrutinized claims made in Sinclair's 2019 book Lifespan, and has publicly challenged Sinclair's framing of sirtuin biology and NAD+ decline in interviews and written commentary [4]. Coverage from the science-commentary site ipscell.com in 2025 specifically framed this as an ongoing, direct disagreement between the two scientists over how confidently the current evidence supports Sinclair's stronger public claims about reversing aging [2].

This places Brenner in an unusual dual position: he is both a commercially interested party in the NR supplement market, through his Niagen Bioscience advisory role, and a public critic of a competing NAD+-precursor narrative associated with Sinclair's NMN-focused ventures, MetroBiotech and Elysium Health. Brenner's own scientific criticism of Sinclair centers specifically on Sinclair's characterization of sirtuin mechanisms and the strength of evidence for NAD+ decline as a driver of aging, rather than a wholesale rejection of NAD+ precursor supplementation itself, a molecule category from which Brenner's own advisory role benefits commercially [4]. Readers evaluating either scientist's public claims about NAD+ precursors should weigh both men's commercial affiliations, Sinclair's to MetroBiotech and Elysium, and Brenner's to Niagen Bioscience, when assessing the neutrality of either side's framing.

Brenner has received formal recognition for his NAD+ pathway work, including the American Society for Nutrition's 2020 National Scientific Achievement Award, and has continued an active research program studying NAD+ metabolism, its role in genome stability, and its relevance to cancer metabolism, publishing extensively on these topics independent of his industry advisory role [1][3]. He has also co-founded additional companies over his career, including Prohealthspan LLC and, more recently, Alphina Therapeutics and Juvenis, extending his commercial involvement beyond Niagen Bioscience alone [3].

The plain takeaway: Brenner's foundational NR biochemistry is solid, well-cited, peer-reviewed science that predates and does not depend on his later commercial role, but his simultaneous position as Niagen Bioscience's Chief Scientific Advisor and as a public critic of a competing NAD+-precursor company's science means his criticism of Sinclair, while substantively grounded, is not coming from a financially disinterested party either.