12 reasons we age. Only 3 you can change.
A landmark 2023 paper organised the chaos of aging into 12 cellular processes. The longevity industry sells products targeting all of them — but only three have human evidence behind them.
Most longevity supplements target a science that hasn't been validated in humans yet.
hallmarks of aging have lifestyle interventions backed by randomized human trials. The other 9 are still being studied in mice and yeast.
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By the end you'll know
- The three things that actually move the needle on biological aging
- Why every validated intervention shares one underlying mechanism
- Which popular protocols (NAD⁺, rapamycin, senolytics) currently rest on hope, not evidence
In 2013, Carlos López-Otín and colleagues published a paper in Cell that organised the chaos of aging research. They proposed nine "hallmarks" — distinct cellular processes that, between them, account for what biology recognises as aging. The paper became one of the most cited in the history of biomedical research.
Ten years later, the same authors revisited the framework. The 2023 update added three more hallmarks, bringing the total to twelve. It also made visible just how much the science has grown — and how little of that growth has translated into things you can actually do.
The marketing implies an evidence base. The evidence — when you look — implies something else entirely.
The longevity industry has not been subtle in filling the gap. NAD⁺ precursors for mitochondrial dysfunction. Senolytics for cellular senescence. Telomerase activators for telomere attrition. Rapamycin for nutrient sensing. The biology behind each of these is real. The human evidence behind their products is not — at least not yet.
What 2026 evidence actually shows
Aerobic exercise · Resistance training · Modest caloric balance.
NAD⁺ · Senolytics · Telomerase activators · Rapamycin · Microbiome supplements.
The three that actually work
Three hallmarks have RCT-grade human evidence connecting a lifestyle intervention to molecular markers and downstream outcomes. They are simple, free, and famously boring.
An expanding universe of mechanisms — and a much smaller universe of validated interventions.
Source: López-Otín et al., Cell, 2023. Categorisation reflects an editorial reading of the human RCT literature as of 2026 — primarily CALERIE 2, LIFE Study, and meta-analyses of resistance training trials.
Why the validated three look so much alike
Anyone who reads about longevity will notice a pattern: the validated interventions all sound boring, and they all sound similar. Move your body more. Lift things. Don't constantly overeat. There's a reason for the similarity.
The three validated interventions sound alike because they share one mechanism — and that mechanism happens to be free.
Your body has two modes.
Modern life keeps us in one of them constantly. The validated interventions briefly tip us into the other.
The other nine — and why they sell
The remaining nine hallmarks are real biology. The cellular processes are well-established. What's missing is the leap from biology to validated lifestyle intervention in humans.
NAD⁺ precursors raise NAD⁺ in human blood. Whether that translates to slower aging in humans remains unproven. Senolytics (drugs that clear senescent cells) make mice live longer; human trials are early and small. Rapamycin and metformin show effects in animals, but their use for "longevity" in healthy humans is currently off-label experimentation. Telomerase activators and microbiome supplements rest on observational and mechanistic evidence — not RCTs of aging-relevant outcomes.
None of this means the products are useless or that the underlying biology is wrong. It means the interventions are still in the period where animal results haven't yet replicated in humans at the scale and duration needed. Some will. Some won't. The next decade will move some of these into the validated category. Until then, the honest framing is: reasonable bets for those willing to take experimental risk, not validated practices.
Where do you stand?
Of the three lifestyle interventions with strong human evidence, how many are you actually doing? Check the ones that are part of your week — not aspirationally.
Not a medical assessment. The three checks reflect interventions with the strongest human evidence as of 2026 — they don't replace clinical guidance, and don't capture every meaningful health behaviour.
What this means in practice
The expansion from nine hallmarks to twelve is, in one sense, good news. Aging biology is moving fast, and the framework is robust enough to absorb new findings without breaking. The next decade will likely see further expansion — and, with luck, the migration of some currently dim entries into the validated category.
Until that happens, the honest synthesis is this: the most valuable things you can do for your healthspan are the three things human research has been telling us for decades. Move enough that your heart and lungs adapt. Lift enough that your muscles don't shrink. Avoid the chronic excess that keeps your body in build mode permanently.
The asymmetry to notice: the validated three are free, available now, with decades of safety data. Most of what's marketed against the other nine is expensive, recent, and rests on evidence that hasn't yet matured. That doesn't mean don't try them. It means try them with eyes open about what you're betting on.
References
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Hallmarks of aging: an expanding universe López-Otín C, Blasco MA, Partridge L, Serrano M, Kroemer G. Cell, 2023;186(2):243-278. Read on Cell
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Effect of structured physical activity on prevention of major mobility disability: LIFE Study RCT Pahor M, Guralnik JM, Ambrosius WT, et al. JAMA, 2014;311(23):2387-2396. Read on JAMA
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Resistance training and mortality: a systematic review and meta-analysis Saeidifard F, Medina-Inojosa JR, West CP, et al. Eur J Prev Cardiol, 2019;26(15):1647-1665. Read on Oxford Academic
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Effect of long-term caloric restriction on biological aging: CALERIE trial Waziry R, Ryan CP, Corcoran DL, et al. Nat Aging, 2023;3(3):248-257. Read on Nature Aging
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Sleep disturbance, duration, and inflammation: meta-analysis Irwin MR, Olmstead R, Carroll JE. Biol Psychiatry, 2016;80(1):40-52. Read on ScienceDirect