Longevity glossary

Autophagy is the cell's recycling system: it breaks down and reuses damaged components. Maintaining it is linked to healthier ageing, and several longevity interventions act partly through it.

Cellular senescence is a state in which damaged cells permanently stop dividing but stay metabolically active, releasing inflammatory signals. Their build-up is a recognised hallmark of ageing.

Inflammaging is the chronic, low-grade inflammation that builds up with age and is thought to drive many age-related diseases.

Mitochondrial dysfunction is the age-related decline in the cell's energy factories. It is one of the hallmarks of aging and a target for several longevity interventions.

mTOR is a central nutrient-sensing protein that controls cell growth. Dialling it down — through caloric restriction or drugs like rapamycin — is one of the best-supported ways to extend lifespan in animals.

NAD+ (nicotinamide adenine dinucleotide) is a coenzyme essential for energy metabolism and DNA repair. Its levels fall with age, which is why NAD+ precursors are a popular longevity intervention — though human longevity benefits remain unproven.

Partial (cellular) reprogramming briefly switches on the “Yamanaka factors” to make old cells behave younger without losing their identity. It rejuvenates tissues in animals but is experimental and carries cancer risk.

Senolytics are drugs designed to selectively clear senescent (“zombie”) cells that accumulate with age. They have extended healthspan in mice, but a longevity benefit in humans is not yet proven.

Sirtuins are a family of enzymes that depend on NAD+ to regulate metabolism, DNA repair and stress responses. They are a major focus of longevity research.

Telomeres are protective caps on the ends of chromosomes that shorten as cells divide. Their attrition is one of the hallmarks of aging, though longer telomeres are not simply “better”.

Caloric restriction is a sustained reduction in calorie intake without malnutrition. It extends lifespan in many animals; in humans it improves cardiometabolic markers, with lifespan effects unproven.

Exosomes are tiny vesicles cells release to communicate and shuttle cargo between cells. They are being explored as regenerative and anti-ageing therapies, but human longevity evidence is preliminary.

GLP-1 receptor agonists (e.g. semaglutide) are injectable drugs originally for type 2 diabetes, now major treatments for obesity. Large trials show they reduce cardiovascular events in specific populations.

Hormone replacement therapy restores hormones (e.g. testosterone, estrogen) that decline with age or deficiency. It is an established treatment for specific indications, not a proven general anti-ageing therapy.

Hyperbaric oxygen therapy (HBOT) delivers near-100% oxygen in a pressurised chamber. It is proven for specific medical conditions; its use as an anti-ageing treatment is still experimental.

Intermittent fasting cycles between eating and extended fasting windows. It can aid weight and metabolic health and engages the same pathways as caloric restriction, though long-term human longevity data are limited.

Metformin is a widely used, inexpensive type 2 diabetes drug being studied as a potential geroprotector. Its anti-ageing benefit in non-diabetics is unproven and is the subject of the planned TAME trial.

NMN (nicotinamide mononucleotide) is a precursor the body uses to make NAD+. It is sold to “boost NAD+” for anti-ageing, but human longevity evidence is early and limited.

Rapamycin (sirolimus) is an mTOR-inhibiting drug that extends lifespan in mice more reproducibly than any other compound. Its use for human longevity is promising but unproven, and it carries real side-effects.

Regular sauna bathing is a form of hormetic heat exposure. Large observational studies link frequent sauna use to lower cardiovascular and all-cause mortality.

An epigenetic clock estimates biological age from DNA-methylation patterns. These “aging clocks” are powerful research tools, but are not yet validated to guide individual medical decisions.

Grip strength is a simple measure of hand force that serves as a proxy for whole-body muscle strength. Lower grip strength predicts higher mortality and disability.

VO2 max is the maximum rate at which your body can use oxygen during intense exercise — a strong, measurable marker of cardiorespiratory fitness and one of the best predictors of longevity.

Biological age is an estimate of how old your body seems based on biomarkers, as opposed to chronological age. Several “clocks” aim to measure it, but methods and validation vary.

Frailty is a state of reduced reserve and increased vulnerability to stressors. It predicts falls, disability and death — and, unlike chronological age, it can be improved.

The hallmarks of aging are a set of interconnected biological processes — such as genomic instability, telomere attrition and cellular senescence — that together drive how organisms grow old.