In this week’s newsletter

✅ Introducing LEVITY Knowledge - our new deep-dive, educational section.
✅ The quest for something better than rapamycin.
✅ Inside Rapamycin Longevity Lab’s next move after securing crucial funding.
✅ “Bryan has interpreted the study wrong” - Krister Kauppi responds to the rapamycin controversy.

🤙🏼 Want to connect? Add me on LinkedIn. 🙏🏼 Not subscribed to the LEVITY podcast on Youtube yet? Do it here. 🎧 More of a listener? The LEVITY podcast is also available on Spotify, Apple Podcasts and other places.

Some housekeeping before we begin:

🦉 LEVITY now has a new section called Knowledge - a place for timeless, educational deep dives into the biology of aging and longevity. These pieces don’t go out via email but live on the web, and you can explore them anytime. They’re designed to explain the ideas, people, and mechanisms that shape this field - the kind of stuff that’s worth coming back to. The first post is up now: it’s about antagonistic pleiotropy.

🤫 Next week you can look forward to a new edition of Longevity Builders. I’m very excited about this one - it’s about a company that’s quietly building a new kind of drug platform, one that could open up targets the rest of the world has written off. You want a hint? Think closeness. But on a molecular level.

Longevity Builders is a LEVITY Premium feature, but this upcoming piece will be unlocked and free to read for a limited time. Premium members will be able to read it before anyone else though.

And while you’re waiting - remember Fauna Bio? If you missed the profile I did on them recently, it’s worth checking out.

🐣 No regular sections in the newsletter this week - it's been a busy time wrapping things up before the Easter break, and I’ve been swamped with other work.

But that just means more room to focus on a concise update on mTOR inhibitors - always a hot topic in the longevity community. You'll find it below.

Wishing you a Happy Easter, and see you next week!

Bryan Johnson gave up on rapamycin. Krister Kauppi’s just getting started

In the world of longevity science, the mTOR inhibitor rapamycin has become something of a gold standard - one of the few compounds consistently shown to extend lifespan in multiple species. Originally discovered in the soil of Easter Island (Rapa Nui) and first developed as an immunosuppressant, rapamycin works by inhibiting a protein complex called mTOR (mechanistic Target of Rapamycin), which plays a central role in regulating cell growth and metabolism. By dialing down mTOR activity, researchers believe we can slow down many of the processes associated with aging.

Yet even among its advocates, there’s a growing consensus that rapamycin alone won’t be enough.

To address this gap, Krister Kauppi*, founder of the Rapamycin Longevity Lab, has partnered with Ora Biomedical (co-founded by Matt Kaeberlein) to launch a large-scale screening project that might reshape our understanding of mTOR inhibition.

* Longtime subscribers of LEVITY might remember Krister from earlier features - like this one.

In collaboration with Ora Biomedical, Kauppi and his team have now secured funding to begin high-throughput screening of 301 mTOR inhibitors using Ora's advanced WormBot-AI platform (see video below). It’s the first part of a larger plan to screen over 600 compounds and identify next-generation interventions that could one day outperform rapamycin - both in efficacy and side effect profile.

For Krister Kauppi, this is also about laying the groundwork for advanced combinational therapies - interventions that don’t just slow aging, but potentially solve it. His long-term vision: move from simple one-compound approaches toward powerful, synergistic treatments that can radically extend healthspan and lifespan.

But the field isn’t without controversy. Some voices in the community question whether mTOR inhibition is still the right path forward. High-profile biohackers like Bryan Johnson have moved away from rapamycin, citing side effects and inconclusive results. Krister responds to these concerns in his typically understated and evidence-driven style - drawing on both preclinical studies and new human data. The full Q&A follows below.

First of all, give us the background to this project.

”The reason why my lab Rapamycin Longevity Lab together with Ora Biomedical started this research project was because we need to get the basic longevity data in place and publicly available. We as a field need to get the basics in place and by this we will enable the research to progress from simple compound studies to much more advanced and impactful longevity research. This is aligned with what Rapamycin Longevity Lab is aiming for which is to develop advanced combinational longevity therapies where we use a promising mTOR inhibitor as a base. Our ultimate mission is not just to slow aging but to also solve it. My current assumption is that some type of advanced combinational therapy is most likely the solution which will show the best longevity effect when it comes to radical life extension.”

You’ve recently secured the initial funding, what happens next?

”The first step is now to get the basics in place and after that we will start developing combinational therapies based on this basic data to see how far we can push things. And within three months, we’ll have unique data to present thanks to the first subproject that has now been funded. And a good thing is making this data publicly available. Other researchers and labs can also start using this data to push things forward. If we want to achieve radical life extension then multiple parties need to work at solving this problem. By sharing especially basic data we help each other to take more advanced steps in our research forward.”

There are some in the longevity community that feels strongly that mTOR inhibition is not the way forward because the overall effect on aging is too small.

”Yes, I fully agree with this. A single compound like the mTOR inhibitor rapamycin will not result in any big longevity effect. Some speculate it may give 5-15 years extra by slowing down the aging rate but this is far from enough if we want to live radically long and well. To achieve this goal we need much more advanced and impactful interventions as I mentioned. This is also what Rapamycin Longevity Lab is aiming for.”

Bryan Johnson claims rapamycin made him age faster - what's your response to that?

”I don’t think Bryan Johnson has claimed that rapamycin has made him age faster because he has not presented any biomarkers or anything like that which has shown this. The only thing he has done is to refer to a study where 16 epigenetic clocks were used to evaluate 51 longevity interventions. In that great study rapamycin did not show any significant negative or positive effect on epigenetic clocks. One important reason for this was most likely because the effective dose of rapamycin was very low. The dose in that study was 1.4 mg/weekly and 2.9 mg/weekly but the average dose regime in the longevity field is around 6 mg/weekly. So I will not draw any conclusions from this study that rapamycin is not working and definitely not that it accelerates aging. I have talked to the researcher, Raghav Seghal, who is behind this study and he is aligned with this. So Bryan has interpreted the study wrong and this can happen to all of us from time to time.”

Hey, you’ve made it all the way here! Thank you so much for reading! 🫶🏼