Why We Can Only Slow Aging, Not Reverse It | Dr Peter Fedichev

The laws of thermodynamics are for closed systems, the body is not a closed system, it receives energy from the environment so there would be no limit to decreasing entropy and the second law doesnt apply.

Good point about dogs being easier to study since they age five times faster than humans. I wish they had also discussed mammals at the other extreme, such as Greenland sharks, which typically live longer than 400 years.

To be honest, at this point, we know that aging is modifiable, but we don't know whether we can reverse it. We should devote resources both to trying to slow aging and to reverse it via therapeutics. For the record, I believe that the information theory of aging is valid, and therefore, I believe that aging is at least somewhat reversible. Also, keep in mind that we don't need to turn 90-year olds into 20-year olds in order extend healthy lifespans via age reversal. We just need to be able to turn 90-year olds into 60-year olds... or maybe turn 80-year olds into 60-year olds (ideally... to turn 90 year olds into 50 year olds).

Among the animals Animals that live very long are... Move very slowly, metabolize very slowly, digest very slowly, and the heart beats very slowly... And they stay in one place for a long time, and most of them have a cold body temperature.

This is the first time I've heard of the naked mole rat and that it lives 30-40 years, which is astonishing (literally 10x longer) compared to other similar sized rodents. THAT would seem to be an animal worth studying!

Thank you for a great interview. One small but important nuance: Fedichev's work does not claim that 150 years is a fundamental limit on human lifespan. Rather, it suggests that around 150 years is the current "natural" lifespan limit in the absence of therapies that directly intervene in the aging process itself. In Fedichev's framework, such interventions are referred to as Level 3 therapies. The approximately 120-150 year lifespan limit described in the landmark 2021 Nature Communications paper is therefore not a fundamental law of nature. It is an estimate of the natural limit of human lifespan without therapies capable of modifying the underlying aging process. The paper explicitly states: > "The proximity of the critical point revealed in this work indicates that the apparent human lifespan limit is not likely to be improved by therapies aimed against specific chronic diseases or frailty syndrome. Thus, no dramatic improvement of the maximum lifespan and hence strong life extension is possible by preventing or curing diseases without interception of the aging process, the root cause of the underlying loss of resilience. We do not foresee any laws of nature prohibiting such an intervention. Therefore, further development of the aging model presented in this work may be a step toward experimental demonstration of a dramatic life-extending therapy." In other words, curing cancer, heart disease, Alzheimer's disease, and other age-related diseases one by one is unlikely to dramatically increase maximum human lifespan. Aging itself must be addressed. In subsequent work, Fedichev proposed a framework of longevity interventions: • Level 1 therapies improve health and function through repair and rejuvenation. • Level 2 therapies postpone age-related diseases, and may extend healthy lifespan beyond 100 years. • Level 3 therapies directly control the fundamental aging process, preventing the progressive loss of resilience and functional capacity that ultimately determines lifespan. The 120-150 year lifespan limit applies to humans in the absence of effective Level 3 therapies. This distinction matters. Physics, biology, and observations of mammals such as naked mole rats suggest that such interventions may be possible. No known law of nature prohibits them. Popular overview: [https://lifespan.io/playing-the-long-game-towards-radical-life-extension/](https://lifespan.io/playing-the-long-game-towards-radical-life-extension/) Scientific paper: [https://www.biorxiv.org/content/10.1101/2025.08.25.671954v3](https://www.biorxiv.org/content/10.1101/2025.08.25.671954v3) Nature Communications 2021 paper: [https://www.nature.com/articles/s41467-021-23014-1](https://www.nature.com/articles/s41467-021-23014-1) The original Nature Communications paper became one of the most downloaded life science papers of 2021 and was covered by Scientific American and Popular Mechanics. Its ideas are likely to influence future biology textbooks. Five years later, its central prediction remains unchanged: dramatic life extension may be possible, but it will require interventions that target aging itself, not merely its consequences. This is precisely what Gero, founded by Fedichev, is working to develop, alongside therapies for age-related diseases and Level 2 aging interventions.

thank for a great interview!

If you would like to support our channel please consider joining our Patreon https://patreon.com/ModernHealthspan *Qualia* (15% off: MODERN) Creatine+ https://tinyurl.com/mr3z35jd Senolytic https://bit.ly/4jlaibe *Renue By Science* (10% off: MHS) https://tinyurl.com/bdew4bfs NMN Powder • Lipo NR *BiOptimizers* (15% off: MHBIO) https://bit.ly/47VAa8f - Magnesium Breakthrough, Gluten Guardian *Seeking Health* (10% off: Richard10) https://crrnt.app/SEEK/-dm0MyrQ, Histamine Nutrients https://crrnt.app/SEEK/EpM7paAO *Stemregen* (15% off: MODERN) *US only* https://tinyurl.com/45z968yr *MitoQ* https://tinyurl.com/5n93fm3f MitoQ Pure https://tinyurl.com/3hxy9s7x *Wellness Extract* (10% off: MODERNWE) http://wellnessextract.com/RICHARDWE Geranylgeraniol • Vit E *n1o1* (10% off: Modern) https://tidd.ly/3IczGRW - Nitric Oxide Lozenges *AX3 Life* (20% off: MODERN20) https://tinyurl.com/2t3w26nw - Astaxanthin *Qitone* (10% off: HEALTH10) https://tidd.ly/4jGklry Qitone Esters Powder *Oxford Healthspan* (15% off: MHS) https://tinyurl.com/hrxfnzpn - Spermidine *ProHealth* (15% off: MODERN) https://prohealth.pxf.io/aObQRR NMNH 500mg

Interesting content 👍🙏

I do not get it, why not talk about individual cells? We know we can reverse the age of an individual cell, we have been doing that in a lab for more than a decade now, so why would we not be able to reverse the age of all the cells in the body at some point in future?? I know reversing the age of the mitochondria is more difficult but enven that can be resolved in the lab by replacing the old mitochondria with new fresh ones. Theoretically this can also be done on scale and replace most of the old mitochondria with young ones in the body.