An Anonymous Longevity Enthusiast Unmasks Himself

@agingdoc1 has revealed himself as David Barzilai.


David BarzilaiDavid Barzilai

A prolific anonymous poster who became popular in the longevity community has revealed his identity, and other longevity luminaries have chimed in.

The anonym

Anonymity is seldom practiced in the longevity community. Everyone knows everyone, and on social media, most people use their real names rather than cloak themselves behind handles. Of course, for every rule, there’s an exception.

Over a few years, an account on X (formerly Twitter), @agingdoc1, gained popularity in the community while remaining completely anonymous. The mysterious owner proudly displayed their degrees, which included MD and PhD, but not their name. The account posted plenty of  links to studies, old and new, related to aging (sometimes quite loosely), mostly without any commentary. However, when the anonym did choose to comment on a paper, it was usually succinct and insightful.

At some point, most of my Twitter notifications (admittedly, I’m not very active there) were coming from @agingdoc1. I tried to deduce the poster’s location and sleeping hours from their tweeting patterns but failed. Notifications just seemed to keep coming at all times.

There are several great accounts that post geroscience-related papers, but @agingdoc1 became my and many others’ personal favorite. There was something trustworthy about this minimal amount of personal touch on the otherwise impartial background. Even when studies were not top-quality, it did not reflect on the poster, as you assumed they were aware of it, too. If @agingdoc1 posted it, it somehow belonged in the mix. Importantly, @agingdoc1 never clashed with anyone or bashed anyone, never pushed their own opinion, and never promoted stuff. All in all, it was a very agreeable anonymous account.


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Somewhat unsurprisingly, it turned out that behind that handle, an equally agreeable human being had been hiding. A couple of weeks ago, the user @agingdoc1 revealed his true identity. His name is David Barzilai, he’s based in Boston, and he’s not connected to the star geroscientist Nir Barzilai. David came out of the shadows with a bang, announcing the launch of a podcast and of a longevity consulting service, so there was a lot for us to talk about when I asked him for a Zoom chat, and he kindly agreed.

Deep passion for everything longevity

First, David is not strictly a geroscientist in the sense of having a basic science lab, but he’s very enthusiastic about this scientific field. He says that his Ph.D. in health services (clinical) research and a strong background in evidence-based medicine offer him a unique perspective for evaluating and contributing to the field. However, he has degrees in abundance, and even calls himself “a degree hoarder.” He’s a practicing dermatologist, although he’s not doing it full time so that he can devote enough attention to his family and his passion, which includes longevity and making a personal impact in other ways.

I’ve always been very interested in my health since I understood that life naturally is finite. That sort of existential dread may have been part of what fueled a lifelong, extraordinarily deep passion. But I also had other things that led me to go into medicine. I’m fascinated by biology. I have a B.S. in cell and developmental biology. My B.A. in health and society is extremely diverse and includes things like community medicine, public health, medical anthropology, philosophy of medicine, medical sociology, history of medicine, and philosophy of health. That’s my background. To summarize, I have two bachelors, two masters, and two doctorates.

In addition to the two bachelor’s degrees and an M.D., David holds an M.Sc. in psychology, an MBA, a Ph.D. in health services research, and a couple of certificates, one of which, abbreviated as DipABLM, means “Diplomat of the American Board of Lifestyle Medicine.” This sparked my interest, and we made a brief detour into what lifestyle medicine is and how it differs from longevity medicine.

It’s a special exam that physicians can take regardless of specialty. As to how it differs from longevity medicine, lifestyle medicine relates to improving one’s health with a high emphasis on prevention through things in your lifestyle. This includes diet, sleep, your exercise, but also your relationships, your stress, your meaning, your circadian rhythm – a truly holistic approach.

Apparently, where longevity medicine turns to rapamycin, lifestyle medicine might choose keeping a healthy weight, staying physically active, pursuing a cleaner diet, getting better sleep, and generally “living healthy.”

The Twitter years

Several years ago, David decided to make the world better by sharing his excursions into longevity research literature.


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I started off on Twitter because I was doing all these super-duper deep dives, healthy longevity pursuits for myself, my family, my friends, and I thought to myself, since I invest all that time in those literature searches, wouldn’t it be great to just put it out there for everyone’s benefit? And even if I disagree with some of what I find, this can be a foundation for a mutual discovery conversation. I would not have the time to discuss what I post at length, but I could be part of a larger ecosystem that self-corrects by inviting scientists and science communicators and, hopefully, changing minds and aligning individuals in the process, while also being a resource for geroscientists and longevity enthusiasts.

For me, it’s the adventure. It’s exploring the boundaries of this extremely deep hobby, passion, and, at some level, maybe obsession with learning everything that improves one’s healthspan, happiness, and even growing as a person, finding your one’s calling and life’s meaning. My Twitter activity was born from the healthspan aspect of it. I thought it would let people identify both good studies that are interesting and also bad studies. I’m not commenting much on the articles, except when I really feel it does good.

David is obviously aware of the existence of other accounts that post studies, but according to him, “none of them is as broad”. He lets himself go “off-topic” from time to time. This, he says, reflects his personality, interests, and attempt to make an impact in the lives of his readership. He’s also trying to “foster communication that’s free from all hype, nonsense, self-promotion, influence, etc.” “This can’t be perfect,” he admits, “anyone has their biases, including me. But maybe I can create a safe haven that’s friendly to everybody, where people can actually discuss topics.”

His success on Twitter came as a surprise even to himself.

My first followers were very small in number, but they had a lot of followers themselves. So somehow, even though I was mostly posting publications, I’d make a comment or two that probably made them think, ‘Oh, this guy seems to know what he’s talking about. He’s not just posting things, he’s not just a bot, he’s actually bringing an interesting perspective that I hadn’t considered’.

“I came up with something I thought would be novel in this crowded space,” he says about his ‘hybrid’ approach. “I broke every rule because most people either do listservs or they give their opinions. I don’t give opinions, but then I do a little bit,” he laughs. “I want a place where people can feel safe, no matter what they believe, and maybe they’re more likely to show up there, and maybe their own mind will be changed because they found a place where they can actually speak their mind.”

Like many people in the longevity space, David has a broad and inquisitive mind that often digresses into wider philosophical musings:

It’s also what democracy needs. Individuals to be able to discuss difficult problems, to really link minds and have the right focus, which is the focus on science, data, and treating each other with dignity, kindness, and respect, even while disagreeing. It’s OK to be critical about an analytical point but not saying that your opponent is a bad person or that they are motivated by greed. It’s OK to discuss matters of motivation, but we need to ask ourselves, in a given situation, what is most helpful for true progress? I believe most people are good at heart, and even if, in some situations, they are not, what good does it do to shame and mock people? It’s just not constructive. It ultimately is far more constructive to engage with people in a collegial manner, regardless of whether or not we agree with them, or even how we feel about their character in some instances.

But why stay anonymous for so long? Apparently, it’s not that simple to explain, and much thought went into this:

I thought to myself, who knows, maybe someone on Twitter, for instance, my patients, would recognize me. And I didn’t want them to think that if I’m talking about caloric restriction on Twitter, that’s also my advice to them, that’s what I think they should do. I’m not practicing longevity medicine on them, I’m wearing another hat when I’m on Twitter – this was very important to me.

There were other factors David had to consider. “All my decisions are multifactorial,” he says. “I’m constantly thinking about multiple variables, trying to optimize my behavior. So, that’s my gestalt of it. I decided to remain anonymous because I didn’t have to disclose my identity, and it seemed marginally better than the opposite option.”

“Project 49”

If remaining anonymous was the best thing to do for so long, why did he decide to emerge from the shadows? In part, it was acting on impulse. Usually, seeing the first digit of your age change is what might jolt you out of complacency and cause you to make resolutions you probably won’t keep. But being the thorough and forward-planning person he was, David felt an itch to shake things up when he turned 49.

On that birthday, I said to myself that I wanted to do more. I felt it was selfish for me to sit on my skill set, which is extremely deep, although you can’t tell that from my Twitter posts because of how rarely I comment on them. So, I thought, hey, if I coach and consult in this area, that would be so much fun and a phenomenal opportunity. And even though it came at some cost in terms of privacy, I owed it to myself and others.

This triggered my interest. I have interviewed many people from the budding realm of longevity medicine, but the concept of longevity consulting was new to me.

Basically, David wants to talk to people about longevity, lending them his expansive knowledge in the field, but also his skills as a life coach. It’s a concierge service where David offers Zoom appointments, starting with 10-minute-long introductory chats. These are strictly audio for his primary coaching service. “I’m not keen on video,” he says, “so I priced it so that very few would want to do it, but I would do a great job if somebody wanted video.”

Who would be his clients? Anyone, he says, starting with scientists and biohackers. Scientists might want to dip into his “deep command of literature,” running by him their thoughts and hypotheses. Biohackers might want to consult him on the intricacies of rapamycin regimens or on other potentially geroprotective drugs that can be taken off-label, such as canagliflozin.

A potential client might think: I’m reading this and that about a molecule or a treatment. They might want to bounce by me some things that they read and hear my thoughts, knowing I’m not going to say, ‘you must do this.’ I basically provide some expertise and an intelligent peer to discuss that. After all, this is a passion project for me. I want to emphasize that this coaching and consulting is not delivery of medicine, so no diagnosis or treatment such as medication is rendered. Rather, I support my clients in a collegial relationship with content expertise and as a sounding board on evidence and practices.

According to David, this will never become a big business, it’s just not scalable. And it’s not like David, with his MBA degree, doesn’t know how to turn this into a big business. He’s just not there for the money. It’s more about making a difference, not necessarily on a large scale, and applying his deep knowledge of the field he loves. He doesn’t intend to devote too much time to his practice. “I just thought it would be fun to do this for a few hours a week and exercise this part of me,” he says. Does he have a system? Not really.

Most other specialists have standardized algorithms for the highly defined populations they see. I do have my mental checklist and a strong framework, but all good coaches and consultants listen to the client, they want to know their objectives, personalizing the relationship around those values and needs. So, I try to get a sense of that and build the conversation accordingly. The sky is the limit. We could literally spend the whole time talking about their relationship with their kids or considering switching jobs – or about the finest minutiae of rapamycin in different protocols that have been tried in the literature, as long as we’re both having fun and it’s two intelligent people having an open discussion and deciding together how to spend our time.

In David’s view, various aspects of well-being and happiness come together to create a better and longer life:

On that same webpage, people can also choose the life coach track and I can go back and forth in between. Just to make it clear, I enjoy life coaching. I want every single person to walk out extremely happy.

While David says those who “gravitate towards him” tend to be M.D.s and Ph.D.s, novices are also welcome:

People can come to me with zero knowledge, and what I want to do is responsibly start with the basics for those individuals. With such people, I would start very heavily on low-hanging fruit, such as nutrition. I would try to understand what aspect of their healthspan is most important to them and what tradeoffs they are ready for. It’s just like when constructing a well-balanced portfolio. Everyone’s goals, their time horizon, their abilities are very individualized, just like everyone’s financial situation is different.

I enjoy working with individuals who are not experts in longevity, and just want guidance because it feels like I’m nurturing them, taking care of them, listening, discovering them. I’m very glad to be able to help them take those first steps and move their life in the right direction.

In fact, the average person that I encounter just wants to have a healthy, happy, well-balanced regular life. And that’s what I want for them. Health is a resource, one of many, just like economics and communities. They’re all aspects and facets to a well-balanced life that combines happiness, purpose, and meaning.

It’s also important for David to stay agile and responsive to new data. “I don’t sell products or invest in things that I peddle,” he says. “I want to be able to quickly change my opinions and recommendations whenever the evidence changes.”

A podcast is born

David did not want to abandon Twitter because it was “a way to reach everyone” but decided to spice things up. He launched the Agingdoc Podcast, immediately aiming at two big names in geroscience: Matt Kaeberlein and Aubrey de Grey.  Currently, it contains the first part of David’s interview with de Grey and two parts of his interview with Kaeberlein.

Just like with his Twitter persona, David thinks he’s found a winning combination of qualities for his newborn podcast:

I tried to go deeper into the science, issues, and controversies than introductory podcasts, while having a constructive conversation in a very friendly, mutually respecting way. It’s two intellectuals talking about how we think about this or that. I’m also trying to be very friendly and let the guest articulate their vision. This also relates to an extension of my role on Twitter. What makes it unique, in my view, is that I’m trying to have a place where it’s about intellect, respect, good data, and us being all on the same team. We all want to get healthy. We all want longevity.

If the description sounds a lot like Peter Attia’s podcast The Drive, it might not be a coincidence since David mentions The Drive as “the gold standard.” Others of David’s favorites are Translating Aging by BioAge Labs, Live Longer World by Aastha Jain Simes, and the podcast by VitaDAO, a decentralized geroscience organization and Lifespan.io’s long-time ally. One of David’s first appearances after the “uncloaking” was on the popular Eleanor Sheekey’s podcast.

Dr. Kaeberlein was one of the first people in the longevity community to learn about David’s identity:

I first got to know @agingdoc1 as David Barzilai when he asked me if I would be willing to publicly confirm his credentials as an M.D. Ph.D. while keeping his identity private, which I agreed to do. He shared proof of his educational background with me, and I posted on Twitter that I’d confirmed his educational background at his request. During the course of our first conversation, I quickly perceived that David is a genuinely good and honest person who cares deeply for his patients and also has a passion for geroscience. After that, David and I kept in touch by email, and a few months later, he told me he was planning on ‘coming out’ and that he would be starting his own podcast. I happily agreed to be one of the first people he interviewed.

As is apparent from his posts and podcast, David has a breadth and depth of knowledge in the field that is quite impressive. He’s also a critical thinker, which is something I personally value highly, although he’s too nice to express critical opinions publicly very often. This is actually something we’ve talked about quite a bit, and I think still have somewhat different opinions on. I’ve encouraged David to be less hesitant to call out flawed science as such, instead of just presenting it without comment.  He argues that he can do more good as a consistently positive voice. Maybe he’s right. Either way, David Barzilai aka agingdoc1 is a good man, a friend, and a valuable member of our community.

Dr. de Grey, David’s second interlocutor, did not know him before appearing on his podcast, but he’s happy to welcome him to the party: “From the interview, I can say that I’m very pleased that someone who has been following the field for so many years has decided to become a full-fledged member of the community.”

With his eloquence, clout, and passion for science communication, would David consider becoming even more public, sort of an ambassador for the field? He stresses that, although he wants to make a difference, first and foremost, he’s committed to his own and his family’s health, longevity, and happiness. “Do I see myself as a sort of public figure? Sure, to the degree to which I can leverage my earned credibility to deliver hype-free, responsible education.”

Optimism and pessimism

Since David struck me as a thoroughly optimistic person, I wondered whether his optimism, combined with his deep knowledge of the field, extends to the current state of affairs in geroscience.

There are reasons for pessimism and reasons for optimism, and they coexist. I simultaneously marvel about how much insight we have compared to what we used to but also, at the same time, how little we understand. In relative terms, we know so much more compared to what we knew before, we understand things so much better than before. We already have to decentralize the knowledge we’ve acquired because it’s just unfathomable. But the fact that it’s unfathomable for the human mind doesn’t mean it’s not possible with technology.

But there’s room for pessimism, too, from the standpoint of how much progress we’ve made in terms of maximum life extension. We’re slowly learning to stop all the more common things, and then we still all die at about the same time, as everything just peters out. I think this is the hard part: this simultaneous petering out of various systems. This is going to be the hardest thing for us to crack. The maximum we’ve achieved in model organisms is around 60% maximum lifespan extension with caloric restriction, and that’s in a mouse – a model that might be less optimized for aging than we are.

So, we haven’t really come up with anything that’s much better. Rapamycin is doing better than anything else, and it still doesn’t extend lifespan in those model organisms as much as caloric restriction does in some rodent strains. And nobody’s talking about calorically restricting humans or expecting humans to respond the same way.

That didn’t sound optimistic, but then David explained further:

There’s also a part of me that admires how far we’ve come in our fundamental understanding and in our basic tools. Some of these tools, I believe, are game changers – not just will they be game changers, they already are. I see publications coming out now, I see accelerating progress. Those tools are changing the game not directly, but by accelerating the rate of progress, and I mean things like single-cell sequencing, CRISPR, so many more and, importantly, those new much, much more sophisticated AI models.

So, according to David, while we still haven’t solved aging, we have acquired tools so powerful that they might soon drive an exponential increase in our knowledge and abilities.

I thought this was a great capstone for our interview, but David wasn’t done just yet. Spotting something in my tone of voice, he asked if I was feeling okay emotionally. A bit surprised, I said I wasn’t because I had a fight with my best friend the day before. I ended up receiving a bit of advice that was simple but effective. I don’t know whether following it prolonged my lifespan, but it felt good, so it might have.

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About the author
Arkadi Mazin

Arkadi Mazin

Arkadi is a seasoned journalist and op-ed author with a passion for learning and exploration. His interests span from politics to science and philosophy. Having studied economics and international relations, he is particularly interested in the social aspects of longevity and life extension. He strongly believes that life extension is an achievable and noble goal that has yet to take its rightful place on the very top of our civilization’s agenda – a situation he is eager to change.