The Longevity Glossary: 60+ Terms Explained (2026)
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Longevity science has its own language, and it’s growing fast. If you’ve ever felt lost when someone mentions “senolytics,” “mTOR,” or “epigenetic drift,” you’re not alone. Having these longevity terms explained clearly is now genuinely useful, not just for biohackers but for anyone who wants to make informed decisions about their health. This glossary covers more than 60 key terms from the longevity and aging science world, organized by category, with honest plain-English definitions and real science behind each one — and if you want to see these concepts in action, our roundup of longevity research 2026’s biggest findings is a natural next read.
By The Longevity Dose Editorial Team · Evidence-reviewed · Last updated June 2026
Key Takeaways
- Longevity science uses precise technical vocabulary that often gets misused or oversimplified in mainstream media and supplement marketing.
- Evidence shows that centenarians in a 2025 Geroscience study (PMID 39520650) showed significantly lower cancer severity than non-centenarians, suggesting extreme longevity and disease resistance are linked at a biological level.
- Understanding terms like “healthspan,” “biological age,” and “hallmarks of aging” helps you evaluate supplements and protocols more critically, rather than falling for marketing claims.
- Many longevity terms describe processes with strong animal evidence but limited human data — and that distinction matters enormously when you’re deciding whether to spend money or change your lifestyle.
Why a Longevity Glossary Matters in 2026
Longevity science has moved from fringe to mainstream at remarkable speed. The global anti-aging market was valued at over $67 billion in 2023, according to Statista, and continues expanding. With that growth comes a flood of jargon, some of it meaningful and some of it marketing spin dressed up in scientific language.
The problem is real. A supplement company can use the word “autophagy” on a label without telling you that most autophagy research was done in yeast and mice. A wellness influencer can say “epigenetic reprogramming” without mentioning that human trials are still in their infancy. Without a working vocabulary, you can’t tell the difference between genuine science and wishful thinking.
This glossary exists to close that gap. Every definition here reflects how researchers actually use the term, with honest notes on evidence strength where it matters.
Longevity Terms Explained: The Biology of Aging
These are the foundational concepts. Understand these and everything else clicks into place.
Hallmarks of Aging
A framework, first published in Cell in 2013 and updated to 12 hallmarks in 2023, that describes the core biological processes that drive aging. They include genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, disabled macroautophagy, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, chronic inflammation, and dysbiosis. Our full guide to the 12 hallmarks of aging explains each one in detail.
Healthspan vs. Lifespan
Lifespan is how long you live. Healthspan is how long you live well, free from serious disease or disability. The goal of most longevity research isn’t just to add years. It’s to compress the period of decline at the end of life and extend the years of full function. These two concepts are often confused, but they’re not the same thing.
Biological Age vs. Chronological Age
Chronological age is simply how many years you’ve been alive. Biological age is an estimate of how old your body’s cells and tissues actually function, based on molecular markers. Biological age can be lower or higher than your chronological age depending on genetics, lifestyle, and environment — and the key longevity biomarkers to track in 2026 are what researchers use to measure that gap precisely. For a full breakdown of how this is measured, see our guide to biological age testing.
Epigenetics
Epigenetics refers to changes in gene expression that don’t alter the DNA sequence itself. Think of your DNA as hardware and epigenetic marks as software. Aging causes epigenetic drift, meaning those marks shift in ways that disrupt normal gene function. This is one of the most active areas of longevity research as of 2026.
Epigenetic Clocks
Mathematical models that use patterns of DNA methylation (chemical tags on DNA) to estimate biological age. The most widely used include the Horvath clock, the Levine PhenoAge clock, and the newer DunedinPACE clock, which measures the rate of aging rather than just current age. Our explainer on epigenetic clocks and how they work covers the science in depth.
DNA Methylation
A chemical process in which a methyl group attaches to a specific site on DNA, typically switching genes off. Methylation patterns change predictably with age and are the basis of most epigenetic clocks. Some patterns are associated with accelerated aging and disease risk.
Telomeres
Protective caps on the ends of chromosomes, similar in function to the plastic tips on shoelaces. Telomeres shorten each time a cell divides. When they become critically short, the cell can no longer divide safely and either dies or enters senescence. Telomere length is one marker of biological aging, though as our deep dive on telomere length and aging explains, it’s an imperfect one on its own.
Telomerase
An enzyme that can rebuild telomere length. It’s active in stem cells and cancer cells, but largely inactive in most adult somatic cells. Activating telomerase is a theoretical longevity strategy, but uncontrolled telomerase activity increases cancer risk significantly.
Senescent Cells (Zombie Cells)
Cells that have stopped dividing but refuse to die. They accumulate with age and secrete a cocktail of inflammatory molecules called the senescence-associated secretory phenotype (SASP), which damages surrounding tissue. Clearing them is the target of senolytics research. Read more in our deep dive on senolytics and zombie cells.
SASP (Senescence-Associated Secretory Phenotype)
The inflammatory chemical signals that senescent cells release into surrounding tissue. SASP includes interleukins, chemokines, and proteases that promote chronic inflammation and can push neighboring healthy cells into senescence. It’s a key mechanism linking cellular aging to systemic disease.
Inflammaging
A coined term for the chronic low-grade inflammation that increases with age and underlies most age-related diseases. It’s driven partly by SASP, partly by accumulated cellular debris, and partly by immune system dysregulation. Inflammaging is now recognized as one of the 12 hallmarks of aging.
Proteostasis
The cellular maintenance system that ensures proteins are properly folded, functional, and cleared when damaged. Proteostasis declines with age, leading to accumulation of misfolded proteins, which is a feature of diseases like Alzheimer’s and Parkinson’s.
Mitochondrial Dysfunction
Mitochondria generate most of a cell’s energy (ATP) and regulate apoptosis (programmed cell death). With age, mitochondria become less efficient, produce more reactive oxygen species (free radicals), and trigger downstream damage. Mitochondrial dysfunction is a recognized hallmark of aging across species.
Cellular and Molecular Longevity Terms
Autophagy
From the Greek for “self-eating,” autophagy is the process by which cells break down and recycle damaged components. It’s a quality-control system for the cell. Fasting, exercise, and caloric restriction are the best-studied triggers of autophagy in humans. Our full explainer covers what autophagy is and how to trigger it.
mTOR (Mechanistic Target of Rapamycin)
A key cellular signaling hub that regulates growth, metabolism, and autophagy. When mTOR is active (stimulated by nutrients and amino acids), cells grow and divide. When mTOR is suppressed, autophagy increases and cellular repair ramps up. The drug rapamycin inhibits mTOR and is among the most-studied longevity interventions in animals.
AMPK (AMP-Activated Protein Kinase)
A cellular energy sensor activated when energy is low, such as during fasting or exercise. AMPK activation suppresses mTOR, promotes autophagy, and improves mitochondrial function. Metformin and berberine activate AMPK, which is one reason both are studied for longevity.
Sirtuins
A family of seven proteins (SIRT1 through SIRT7) that regulate gene expression, DNA repair, and metabolism in response to cellular stress. They require NAD+ to function. Dr. David Sinclair’s lab at Harvard has focused heavily on sirtuins as potential longevity targets, though human evidence remains early-stage.
NAD+ (Nicotinamide Adenine Dinucleotide)
A coenzyme found in every living cell, essential for energy metabolism and DNA repair. NAD+ levels decline significantly with age, and this decline is linked to mitochondrial dysfunction and reduced sirtuin activity. Our complete guide to NAD+ and NMN covers the science and supplementation evidence.
NMN (Nicotinamide Mononucleotide)
A direct precursor to NAD+ in the cell. NMN supplementation raises NAD+ levels in human studies. Whether that translates to meaningful anti-aging effects in people remains under investigation as of 2026. Evidence in rodents is stronger than in humans.
NR (Nicotinamide Riboside)
Another NAD+ precursor, and the more extensively studied of the two in human clinical trials. Tru Niagen, an NR supplement, has been used in multiple published human trials. Current evidence shows it raises blood NAD+ levels, but longer-term outcome data in humans is still limited.
Resveratrol
A polyphenol found in red wine and grape skins, popularized as a longevity compound after David Sinclair’s early sirtuin research. Human evidence has been disappointing so far. Most longevity effects were demonstrated in yeast, worms, and mice, not people. See our honest breakdown of whether resveratrol actually works.
Rapamycin
An mTOR inhibitor originally developed as an immunosuppressant. It’s the only drug that consistently extends lifespan in mice across multiple independent studies. Human longevity trials are underway as of 2026, but prescribing it off-label is controversial due to immune suppression risks. Full evidence review: rapamycin for longevity.
Metformin
A widely prescribed type 2 diabetes drug that activates AMPK, reduces blood glucose, and has epidemiological associations with longer life in diabetic patients. The TAME trial (Targeting Aging with Metformin) is a large ongoing human trial testing it in non-diabetics. Results are expected in the late 2020s.
Senolytics
Compounds that selectively clear senescent cells from the body. The best-studied combination is dasatinib plus quercetin, which showed reductions in senescent cell burden in a small human trial published in EBioMedicine in 2019. Research is still early and primarily preclinical.
Senomorphics
Compounds that reduce the harmful secretions (SASP) of senescent cells without killing the cells themselves. They’re a softer alternative to senolytics. Rapamycin has some senomorphic properties. Human evidence is very limited as of 2026.
Longevity Terms for Metabolism and Hormones
Insulin Sensitivity
How effectively your cells respond to insulin to take up glucose from the blood. Poor insulin sensitivity (insulin resistance) is a driver of type 2 diabetes, cardiovascular disease, and accelerated biological aging. Improving insulin sensitivity through exercise, diet, and sleep is one of the highest-leverage longevity interventions with strong human evidence — and sleep and longevity statistics make clear just how much that last factor matters.
IGF-1 (Insulin-Like Growth Factor 1)
A hormone that promotes cell growth and division. Higher IGF-1 accelerates aging in animal models. Populations with IGF-1 deficiency, like those with Laron syndrome, have very low cancer rates. Caloric restriction lowers IGF-1 and may partly explain its longevity effects in animals.
Cortisol
The primary stress hormone, produced by the adrenal glands. Chronically elevated cortisol accelerates biological aging by shortening telomeres, promoting inflammation, impairing immune function, and disrupting sleep. Evidence shows that psychological stress directly damages cellular aging markers. Our guide on stress and aging covers this in full.
Hormesis
The biological principle that low doses of a stressor trigger beneficial adaptive responses, while high doses cause damage. Exercise, fasting, cold exposure, heat, and certain phytochemicals work via hormesis. For a thorough breakdown, see our explainer on hormesis and beneficial stress.
Caloric Restriction (CR)
Reducing daily calorie intake below typical intake without malnutrition. CR is the most replicated longevity intervention in animal studies across species. Human evidence from the CALERIE trial found that 12% caloric restriction over 2 years improved cardiometabolic biomarkers, though long-term lifespan effects in people are unknown.
Time-Restricted Eating (TRE)
Eating within a defined daily window, typically 6 to 10 hours, and fasting the rest. Sometimes called intermittent fasting, though TRE is a more precise term. TRE activates autophagy, lowers insulin, and improves metabolic markers in human studies, though effects vary by eating window and individual.
Autophagy Flux
Not just whether autophagy is happening, but how efficiently the whole process runs from initiation to degradation and recycling. This matters because stalling autophagy flux midway can actually cause cellular harm. It’s a more precise term than “autophagy” alone and is increasingly used in research papers.
GLP-1 (Glucagon-Like Peptide-1)
A gut hormone that regulates insulin secretion, appetite, and gastric emptying. GLP-1 receptor agonists like semaglutide (Ozempic/Wegovy) mimic this hormone. Beyond weight loss, GLP-1 drugs are being studied for cardiovascular protection, neurodegeneration, and potential longevity effects.
Mitophagy
A specific form of autophagy that targets and removes damaged mitochondria. Efficient mitophagy keeps the mitochondrial population healthy and is essential for energy metabolism and longevity. Exercise and fasting are the primary evidence-backed triggers of mitophagy in humans.
Reactive Oxygen Species (ROS)
Chemically reactive molecules containing oxygen, produced as byproducts of normal metabolism. In small amounts, ROS serve as cellular signals. In excess, they cause oxidative damage to DNA, proteins, and cell membranes. The free radical theory of aging was once dominant but is now considered too simple on its own.
Fitness, Exercise, and Performance Terms
VO2 Max
The maximum rate at which your body can consume oxygen during intense exercise. It’s one of the strongest single predictors of both all-cause mortality and cardiovascular longevity. A 2022 study in JAMA Network Open found that low VO2 max carried a greater mortality risk than smoking, diabetes, or hypertension. See our explainer on VO2 max as a longevity predictor.
Zone 2 Cardio
Low-intensity aerobic exercise sustained at a heart rate where you can still hold a conversation but are working steadily. Zone 2 builds mitochondrial density, improves fat oxidation, and is a cornerstone of the longevity exercise frameworks recommended by clinicians like Dr. Peter Attia. Our full breakdown covers Zone 2 training for longevity.
Sarcopenia
Age-related loss of muscle mass and strength, typically accelerating after age 50. Sarcopenia is directly linked to frailty, falls, metabolic decline, and increased mortality. Resistance training is the most effective intervention to slow or reverse it, with strong human evidence. A 2026 study in the Journal of Nursing Research (PMID 41439678) highlighted frailty screening as essential for community-dwelling older adults, underscoring how common and consequential muscle decline becomes with age.
Frailty
A clinical syndrome of decreased physiological reserve and resistance to stressors, increasing vulnerability to adverse health outcomes. It’s typically measured by criteria including unintentional weight loss, exhaustion, low grip strength, slow walking speed, and low physical activity. Frailty is distinct from disability and is potentially reversible with the right interventions.
Centenarian Decathlon
Dr. Peter Attia’s framework for thinking about physical preparedness in old age. The idea is to work backwards from what you want to be physically capable of at 100, then train towards that goal now. His book Outlive: The Science and Art of Longevity explains the concept in full and is widely considered the most practical longevity book available.
Grip Strength
A simple, inexpensive measure of overall muscular strength. Low grip strength is consistently associated with higher all-cause mortality in large cohort studies. It’s used as a proxy for physiological age and muscle health in clinical and research settings.
Lactate Threshold
The exercise intensity at which lactate accumulates in the blood faster than it can be cleared. Training at and slightly above lactate threshold improves VO2 max and cardiovascular fitness. It’s the physiological basis of Zone 3 and Zone 4 training.
Longevity Terms for Interventions and Measurement
Medicine 3.0
Dr. Peter Attia’s term for a proactive, individualized approach to medicine focused on preventing the “Four Horsemen” of chronic disease (cardiovascular disease, cancer, metabolic disease, and neurodegeneration) decades before they occur. It contrasts with Medicine 2.0, which he argues is reactive and disease-focused rather than prevention-focused.
Biological Age Testing
A broad category of tests that attempt to estimate your biological age using molecular markers. Epigenetic clocks (via DNA methylation) are currently the most researched. Other approaches include proteomics, metabolomics, and multi-omics panels. Accuracy and clinical utility vary significantly between products.
Longevity Escape Velocity
A concept promoted by geroscientist Aubrey de Grey, describing the point at which medical advances extend life expectancy faster than a person ages. At that point, a person’s remaining life expectancy increases with each passing year. This remains a theoretical concept with no scientific consensus on when or whether it’s achievable.
Geroscience
The scientific field that studies the relationship between aging and disease, specifically how aging processes drive the development of age-related diseases. The core premise: treating aging itself is more efficient than treating each disease separately.
Geroprotector
Any compound or intervention that protects against aging or age-related damage. The term is used in research to describe candidates including rapamycin, metformin, senolytics, NAD+ precursors, and certain dietary compounds. It’s a category, not a guarantee of efficacy in humans.
Photobiomodulation (Red Light Therapy)
The use of specific wavelengths of red and near-infrared light to stimulate cellular function, particularly mitochondrial activity. Evidence in humans remains early but suggestive for skin, wound healing, and joint pain. Longevity claims go well beyond current human evidence. See our assessment of red light therapy and aging, or dive deeper into the anti-aging applications with our red light therapy anti-aging complete guide.
Cryotherapy / Cold Plunge
Deliberate cold exposure through cold water immersion or cryotherapy chambers. Evidence supports short-term benefits for recovery and mood. Long-term longevity evidence in humans is limited. Some research suggests cold plunging immediately after strength training may blunt muscle adaptation. Our cold plunge science explainer covers the protocols and risks.
Sauna (Hyperthermia Therapy)
Repeated heat exposure via traditional Finnish sauna or infrared sauna. A landmark observational study from the University of Eastern Finland, published in JAMA Internal Medicine in 2015, found that men who used a sauna 4 to 7 times per week had a 40% lower risk of all-cause mortality compared to once-weekly users. Correlation, not causation, but the effect size is notable.
Microbiome (Gut Microbiome)
The community of trillions of microorganisms living in the gut. Microbiome composition shifts with age, and certain bacterial populations are associated with longer life and better immune function. Centenarians tend to have more diverse and distinct microbiomes than younger adults. Our guide explores the gut microbiome and longevity in detail.
Dysbiosis
An imbalance in the gut microbiome, typically characterized by reduced diversity and increased abundance of pro-inflammatory species. Dysbiosis is now listed as one of the 12 hallmarks of aging and is linked to inflammaging, metabolic dysfunction, and neurodegeneration.
Centenarian
A person who has reached the age of 100 or older. Research on centenarians provides valuable insight into the genetic and lifestyle factors associated with extreme longevity. A 2025 study in Geroscience (PMID 39520650) found that centenarians in the Basque Country showed significantly lower cancer severity than non-centenarians, suggesting that extreme longevity may be partly driven by biological resilience to age-related disease rather than simply avoiding risk factors.
Blue Zones
Five geographic regions identified by researcher Dan Buettner with unusually high concentrations of centenarians: Sardinia (Italy), Okinawa (Japan), Nicoya Peninsula (Costa Rica), Icaria (Greece), and Loma Linda (California). Blue Zone populations share several lifestyle patterns including plant-heavy diets, regular low-intensity movement, strong social connection, and a sense of purpose.
Polypharmacy
The concurrent use of multiple medications. In older adults, polypharmacy (typically defined as five or more drugs simultaneously) significantly increases risks of adverse drug interactions, falls, cognitive impairment, and hospitalizations. It’s increasingly relevant in longevity medicine as more drugs are considered for anti-aging use.
Longevity Supplement Stack
A combination of supplements taken together with the goal of supporting healthspan and lifespan. Common inclusions in 2026 evidence-informed stacks include NMN or NR, magnesium glycinate or threonate, omega-3s, vitamin D, and creatine. Our comprehensive longevity supplement stack comparison for 2026 reviews the evidence for each.
Information Theory of Aging
Dr. David Sinclair’s hypothesis, described in his book Lifespan, that aging is primarily caused by the loss of epigenetic information rather than DNA damage itself. Under this theory, the information needed to run the cell correctly becomes corrupted with age, much like a scratched CD. His book Lifespan: Why We Age and Why We Don’t Have To explains this framework in accessible terms.
Yamanaka Factors
Four transcription factors (Oct4, Sox2, Klf4, c-Myc) that can reprogram adult cells back to a stem-cell-like state. Named after Nobel laureate Shinya Yamanaka. Partial epigenetic reprogramming using these factors is one of the most ambitious areas of longevity research, with several biotech companies pursuing it. Human safety data is not yet available.
GeroDiscovery / Gerotranscendence
Emerging terms in geroscience describing the psychological and social dimensions of aging well. Gerotranscendence (sociologist Lars Tornstam’s concept) describes a shift in perspective in later life toward greater life satisfaction, connection, and meaning. It’s gaining attention in longevity circles as evidence grows that psychological wellbeing is a genuine longevity variable.
Quick Reference: Core Longevity Terms at a Glance
| Term | Category | Evidence Strength in Humans |
|---|---|---|
| Autophagy | Cellular biology | Moderate (mechanism confirmed; longevity outcomes limited) |
| VO2 Max | Fitness | Strong (large cohort studies) |
| Senescent Cells | Cellular biology | Early (human senolytic trials underway) |
| Rapamycin | Drug intervention | Preliminary (strong animal data, early human trials) |
| NAD+ / NMN | Supplement |
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