Meet Charles Brenner, the Longevity Skeptic. Brenner, a leading biochemist at City of Hope National Medical Center in L.A., has been attending the largest longevity conferences with one main purpose: to point out that some of the other speakers are full of it.Brenner is "throwing cold water" on several scientists in the field of aging, accusing them of hyping various fountains of youth, despite limited evidence for these therapies. In this podcast episode, Brenner sat down with Leaps.org to discuss these battles. In addition to bringing his candor to the conferences, he's applying it in academic journals, publishing a paper a few months ago in which he disputed claims by Eric Verdin of the Buck Institute that certain ketones and nucleotides, if taken regularly in pill form, can affect aging. In his September paper, "A Science-Based Review of the World's Best-Selling Book on Aging," he pans the author of this bestseller, David Sinclair, a Harvard biologist, for talking up the potential for humans to live far past 100. These aspirations may sound nice, but they're not backed by science, Brenner says.He's had high-profile debates online with Sinclair and Aubrey de Grey, a prominent biomedical gerontologist. Meanwhile, in his own lab work, Brenner is credited with discovering a vitamin precursor that seems to enable repair of cellular damage that happens as we get older - a major discovery that he's helped turn into a supplement, commercialized with a company called ChromaDex.Whether it's possible to extend human lifespan is a pressing question as investments in longevity startups are projected to increase from $40 billion to $600 billion over the next three years. Brenner is an intriguing figure in these discussions. Although he’s been introduced in public appearances as a longevity skeptic, he calls himself an optimist. Links:Charles Brenner, City of HopeCharles Brenner LabCharles Brenner on TwitterCharles Brenner's debate with Aubrey de GreyBrenner's paper, "A Science-Based Review of the World's Best-Selling Book on Aging"Peter Attia's recent blog on NR supplementsBrad Stanfield's reaction to David Sinclair vs Leaps.org is a not-for-profit initiative that publishes award-winning journalism, popularizes scientific progress on social media, and hosts events about bioethics and the future of humanity. Visit the platform at www.leaps.org. Podcast host Matt Fuchs is editor-in-chief of Leaps.org.