Cellular and Mitochondrial Health
Aging is not one process. A 2023 review in Cell groups its drivers into twelve interconnected hallmarks, including genomic instability, mitochondrial dysfunction, cellular senescence, stem cell exhaustion and chronic inflammation. Each one appears with age, speeds aging when it is made worse in experiments, and offers a chance to slow aging when it is targeted.1
Two hallmarks have been studied closely. In 146 healthy adults aged 18 to 89, mitochondrial DNA, mitochondrial RNA and mitochondrial ATP production in muscle all declined with age, and ATP production tracked aerobic capacity and glucose tolerance.2 Senescent cells, which stop dividing and release inflammatory signals, build up in tissues over time; clearing them extended median lifespan in mice and slowed age-related decline in their kidneys, hearts and fat.3 That result is in mice. In people the evidence is early: a pilot trial in nine adults with diabetic kidney disease found that three days of dasatinib plus quercetin reduced senescent-cell markers in fat and skin, but it measured markers, not health outcomes.4
The articles below take each process in turn and separate what has been shown in people from what has only been shown in cells and animals.
Reading path
Read in this order: the essentials first, then the detail, then the reviews that test popular claims.
Start here
- The Hallmarks of Aging: A Plain-Language Guide to the 12 Biological Processes Driving Your DeclineA plain-language guide to the 12 hallmarks of aging, from genomic instability to chronic inflammation, and the interventions aimed at each.
- Mitochondria and Aging: Why the Decline of Your Cellular Power Plants Is Aging — and What to Do About ItHow mitochondria decline with age, why that matters for energy and disease, and what exercise and supplements can and can't do about it.
Go deeper
- Cellular Senescence: What “Zombie Cells” Are and What the Human Evidence ShowsWhat senescent cells are, how they drive inflammation with age, and what senolytic drugs have and haven't shown in early human trials.
- Autophagy: How Your Cells Self-Clean — and Why It Matters for LongevityHow autophagy clears damaged proteins and mitochondria, what switches it on in people, and what the evidence does and doesn't show about fasting.
- Inflammaging: How Chronic Low-Grade Inflammation Is Linked to Age-Related DiseaseHow chronic low-grade inflammation builds with age, the markers used to measure it, and the lifestyle factors linked to lower levels.
Evidence checks
- NAD+, Sirtuins, and Longevity: Separating Genuine Science from HypeWhat NAD+ and sirtuins do, why NAD+ falls with age, and how far human trials of NAD+ boosters support the claims made for them.
- The Gut Microbiome Guide: What Shapes It and What the Health Evidence ShowsA practical guide to supporting your gut microbiome with fiber, fermented foods and other habits, and what probiotics can and can't do.
Sources
- 1López-Otín C, et al. "Hallmarks of aging: An expanding universe." Cell. 2023;186(2):243-278. PubMed · DOI
- 2Short KR, et al. "Decline in skeletal muscle mitochondrial function with aging in humans." Proc Natl Acad Sci U S A. 2005;102(15):5618-23. PubMed · DOI
- 3Baker DJ, et al. "Naturally occurring p16(Ink4a)-positive cells shorten healthy lifespan." Nature. 2016;530(7589):184-9. PubMed · DOI
- 4Hickson LJ, et al. "Senolytics decrease senescent cells in humans: Preliminary report from a clinical trial of Dasatinib plus Quercetin in individuals with diabetic kidney disease." EBioMedicine. 2019;47:446-456. PubMed · DOI