Star Scientist’s Claim of ‘Reverse Aging’ Draws Hail of Criticism

Harvard geneticist David Sinclair, who has said his “biological age” is roughly a decade younger than his actual one, has put forward his largely unlined face as a spokesman for the longevity movement.

The 54-year-old has built his brand on the idea that aging is a treatable disease. The notion has proven so seductive that legions of acolytes follow his online postings about his research and the cocktails of supplements he consumes to stave off the inevitable.

His social-media accounts are a platform for assertions that his work is pushing nearer to a fountain of youth. He claimed last year that a gene therapy invented in his Harvard lab and being developed by a company he co-founded, Life Biosciences, had reversed aging and restored vision in monkeys. “Next up: age reversal in humans,” he wrote on X and Instagram.

On Feb. 29, in the eyes of many other scientists working to unlock the mysteries of aging, he went too far.

Another company he co-founded, Animal Biosciences, quoted him in a press release saying that a supplement it had developed had reversed aging in dogs. Scientists who study aging can’t even agree on what it means to “reverse” aging, much less how to measure it.

The response was swift and harsh. The Academy for Health and Lifespan Research, a group of about 60 scientists that Sinclair co-founded and led, was hit with a cascade of resignations by members outraged by his claims. One scientist who quit referred to Sinclair on X as a “snake oil salesman.”

Days later, in a tense video meeting, the academy’s five other board members pressed Sinclair to resign as president. He contended that the press release contained an inaccurate quote, according to people who were in the meeting, but he later stepped down.

Sinclair’s work is published regularly in top-tier scientific journals and has brought attention to an emerging field vying for credibility and funding. He has parlayed his research into hundreds of millions of dollars of investment in various companies, more than 50 patents and prominence as a longevity influencer.

Along the way, his claims—especially in his social-media posts, interviews and his book—have drawn criticism from scientists who have accused him of hyping his research and extolling unproven products, including some from companies in which he had a financial interest.

“My lab’s ideas and findings are typically ahead of the curve, which is why some peers might feel the research is overstated at the time,” Sinclair said to The Wall Street Journal in an email. “I stand behind my track record as a trusted scientist in one of the most competitive professions of all.” He said he doesn’t engage with social-media critics, including those calling him a snake oil salesman, and that many such comments are “nothing more than mischaracterizations.”

Dr. Nir Barzilai, the new president of the Academy for Health and Lifespan Research and the director of the Institute for Aging Research at Albert Einstein College of Medicine, said Sinclair’s comment about the dog research and his commercial interest in Animal Biosciences crossed a line. “The data is not good, you’re calling it the wrong thing, and then you’re selling it,” he said. “The selling is a step too far.”

Sinclair said he adheres to Harvard’s conflict of interest policies. His dog-supplement company, Animal Biosciences, issued a reworded press release backing away from the claim of reversing aging.

The search for eternal youth has fueled a longevity industry that attracted roughly $43 billion in global investment in the past decade, according to research and media company Longevity.Technology. Companies including Altos Labs and Alphabet’s Calico Life Sciences are studying potential mechanisms and treatments for aspects of aging.

Companies are exploring techniques such as rejuvenating cells, with an aim to reverse diseases and restore cell functions that can diminish with age. Dr. Shinya Yamanaka and John B. Gurdon won a Nobel Prize in 2012 for their pioneering work in cell reprogramming.

The pushback against how Sinclair portrays his work reflects a conviction that a field once considered fringe is gaining legitimacy. As money pours in and scientists start companies, they are assessing one another’s work as both expert colleagues and business rivals.

Some longevity researchers caution that rejuvenating some cells isn’t the same thing as reversing aging in people. “Reversal of aging is a term I stay away from. The evidence in humans isn’t there,” said Dr. Bruce Yankner, a professor of genetics and neurology at Harvard and co-director of the Paul F. Glenn Center for Biology of Aging Research.

Sinclair and other scientists have studied whether substances including resveratrol, a compound in red wine, and the diabetes drug metformin could extend life. Researchers have also explored the potential of supplements including fisetin, found in fruits and vegetables, to eliminate cells that are “senescent” or that have stopped dividing but don’t die. Sinclair has touted all three compounds as part of his own regimen.

Rafael de Cabo, a senior investigator and chief of the translational gerontology branch at the National Institute on Aging, co-wrote studies on resveratrol in mice with Sinclair. He said there isn’t enough evidence to support humans taking the supplement.

“In the absence of some clinical trials with the clinical application, it’s a gamble,” he said. “We do not know what the compound is going to do.”

Dr. Danielle Belardo, a cardiologist in Los Angeles, said she gets requests for off-label metformin from patients who have read Sinclair’s 2019 bestseller, “Lifespan: Why We Age—And Why We Don’t Have To.” She said she encourages patients to stop using supplements, including resveratrol, that Sinclair and other longevity influencers have said they take. “At best, it’s wasted money,” she said.

“I am careful to say that what I do may not be the best thing for others,” Sinclair said. He said evidence shows resveratrol has health benefits in animals and people.

Sinclair was born in Sydney, Australia, and earned a Ph.D. in molecular genetics at the University of New South Wales. At 26, he joined the lab of Massachusetts Institute of Technology professor Leonard Guarente, who was trying to understand the biological causes of aging.

“He has done a lot of good work over the years,” said Guarente, who describes himself as a mentor and adviser.

Sinclair’s public statements, he said, are what often cause controversy. “He cannot put a boundary on his enthusiasm, so it bubbles over and he says stuff,” he said. “I have talked with him many times about it, and he can’t contain himself.”

Sinclair moved in 1999 to Harvard, where he became a tenured professor. His lab there found that resveratrol appeared to prolong the lifespan of mice. Sinclair was one of the founders of a company called Sirtris Pharmaceuticals, which GlaxoSmithKline bought in 2008 for $720 million. Sirtris developed drugs that included a reformulated resveratrol.

GSK stopped a study testing the drug in cancer patients in 2010 over safety concerns. GSK announced in 2013 it was shutting Sirtris.

The National Institute on Aging’s Interventions Testing Program reported in 2011 and 2013 that resveratrol didn’t extend the lifespan of healthy mice. Resveratrol is still being studied in humans, and researchers have reported varying results.

Sinclair started more companies and built his public persona as a longevity influencer. His knack for synthesizing complicated research into bite-size takeaways has attracted health enthusiasts to his appearances on Joe Rogan’s and Peter Attia’s podcasts and his TED talks, including “Can a pill a day keep aging away?” and “A Cure for Ageing?”

His Instagram account mixes images of whiteboards, test tubes and petri dishes with glitzier fare. He posted a photo of Arianna Huffington visiting his lab, and thanked Jennifer Aniston for her support after an Instagram mention of the dog chews made by Animal Biosciences.

Tally Health, a company Sinclair co-founded, sells a test to measure biological age and longevity supplements, including one containing resveratrol. The company’s Chief Executive Officer Melanie Goldey acknowledged the controversy around resveratrol and told the Journal in April that company scientists are independently evaluating its efficacy to determine whether the company still “stands behind” the compound. The company still sells the supplement that includes resveratrol and said it is always reviewing the efficacy of all its ingredients.

In February, Sinclair and his brother, Nick Sinclair, who is Animal Biosciences’ CEO, emailed the Journal about research the company was planning to share about a dog supplement it had developed. “Results from clinical trial in dogs to reverse aging,” said the subject line of one email.

The study, which was conducted by the North Carolina State College of Veterinary Medicine, enrolled 70 dogs. It concluded that even dogs that received a placebo showed cognitive improvement, but those that got a full dose of the supplement showed the largest improvement. The study is undergoing peer review and could change, said Brandon Bieltz, a spokesman for the school.

The release that went out on Feb. 29 quoted Sinclair praising his colleagues for having “developed the first supplement proven to reverse aging in dogs.”

Matt Kaeberlein, a longevity researcher who co-directs a large study on aging in dogs, read the release and felt Sinclair’s claims about the dog supplement went too far. Kaeberlein, who worked in the same MIT lab as Sinclair in the 1990s, emailed more than a dozen peers, including some members of the Academy for Health and Lifespan Research, on March 1 that he planned to resign.

“Conning people into believing that this stuff will reverse aging in their pets is disgusting behavior,” he wrote in an email. Two days later, Kaeberlein publicized his resignation on X, calling Sinclair a “snake oil salesman.”

Sinclair said a public-relations company inadvertently distributed an early version of the Animal Biosciences release. “The actual quote that I had approved was ‘proven to reverse the effects of aging in dogs,’” he said. “I felt this was a reasonable statement.”

The agency, GCW, said it distributed a release the company provided. On March 5, it reissued the release with an amended quote from Sinclair, who said the supplement was “shown to reverse the effects of age related decline in dogs.”

On March 8, Sinclair sent a text to the academy’s internal WhatsApp group apologizing for sharing his view of what constitutes age reversal in a way that brought negative attention to the group.

The same day, the academy’s six board members, including Sinclair, sent an email to members attempting to quell the controversy. “No single member speaks for the Academy,” they wrote.

They promised to expand the academy’s bylaws to outline language people should use in public statements about work in which they have a financial stake.

Three more academy members submitted their resignations soon after. One said in his resignation letter that the response was inadequate from a group of widely published scientists who should know better.

“It slowly became the David Sinclair show,” said Andrew Dillin, a geneticist at the University of California, Berkeley, who resigned. “He’s representing me through the academy, and I don’t want to be associated with that.”

Tony Wyss-Coray, a professor of neurology at Stanford University who also resigned from the academy, said it should form a committee to investigate conflicts of interest. “The academy should be an absolutely clean, scientifically driven guidepost for the public,” he said.

Barzilai, the new president, said he is forming such a committee.

Arlan Richardson, an academy member and biochemist at the University of Oklahoma Health Sciences Center read Sinclair’s dog-supplement study and thought about his fluffy black-and-white Tibetan terrier, Zorro. Pet lovers would pay handsomely for dog chews they thought would extend an animal’s life, he recalls thinking, and that Sinclair was “preying on very vulnerable people.”

He submitted his resignation from the academy.

Barzilai and his fellow board members held a video call that weekend without Sinclair. They decided the academy needed to move forward without Sinclair as its head.

Soon after, they held a video meeting with Sinclair. The words in the original press release had been incorrect, he told them. One board member said it wasn’t the only time Sinclair had claimed to have reversed aging. The conversation was tense. Sinclair agreed to step down as president.

“He’s very hurt,” Barzilai said later.

Sinclair said to the Journal that he regrets using language suggesting age reversal in dogs, and pledged to be “more accurate with my words” in the future. He said he wasn’t asked to step down as president.

Board members of the American Federation for Aging Research, another group of longevity scientists where Sinclair is on the board, are discussing his future participation. Sinclair said he welcomes open conversations with the organizations in which he participates.

The administrator of the Facebook group “Dr David Sinclair Fans” sent a poll March 12 to its nearly 18,000 members asking if they wanted to rename the group “after questionable decision-making by Dr. David Sinclair and his business dealings.” Most of the 250 respondents wanted a new name. The group is now called “Age Reversal Protocols.”

On March 13, the academy’s five remaining board members sent an email announcing Sinclair had resigned as president. “We hope we can move past these events. The Academy is about science and scientists; all else is secondary,” they wrote.

Richardson rescinded his resignation from the academy after receiving the email.

Sinclair was scheduled to appear later that month at a longevity summit in Milan, Italy. He was slated to speak on two panels, including one with Barzilai called “The Peter Pan effect: forever young?”

Sinclair didn’t go. He said he was overcommitted. Another scientist stepped in for him.

Barzilai joked that Sinclair had been replaced as a speaker—“with someone younger.”

Write to Alex Janin at [email protected], Dominique Mosbergen at [email protected] and Amy Dockser Marcus at [email protected]