Human data exists, but no telomere intervention has a healthy-aging lifespan RCT. What exists is telomere-length / telomerase-activity biomarker data (TA-65), clinical outcomes in a rare telomere DISEASE (danazol; nandrolone), a small cancer-cohort pilot (Ornish), and gene-therapy lifespan data in mice (AAV-TERT). "Changed a telomere number in a trial" is not "extended healthy human lifespan."
Two hard truths the field glosses over. (1) Telomere length is a contested aging biomarker — measurement varies by method and tissue, and "longer" is not simply "healthier." (2) Activating telomerase is not risk-free — it raises an unresolved cancer-risk question, and the only FDA-approved telomerase drug, imetelstat (RYTELO, 2024), inhibits telomerase to treat cancer — the opposite direction from anti-aging "activation."

Interventions

Study records

Mechanisms

Evidence tiers

TierLabelNote
1Healthy-aging human lifespan RCTRandomized, hard lifespan/healthy-aging endpoint in a healthy-aging population. NONE exist for any telomere intervention as of the search date — tier empty by design.
2Human clinical-outcome RCT — disease populationRandomized, hard clinical outcome but in a disease population, not healthy aging. Examples: danazol in telomeropathy/marrow failure; imetelstat (a telomerase INHIBITOR) in lower-risk MDS.
3Human RCT — telomere-length / telomerase-activity biomarker endpointRandomized, endpoint is a contested telomere biomarker (telomere length or telomerase activity), not a clinical outcome or lifespan. Example: TA-65 telomere-length RCT (Salvador 2016).
4Human pilot / observational — biomarkerSmall pilot or observational cohort with a telomere biomarker endpoint; no randomized healthy-aging intervention. Examples: Ornish lifestyle pilot; telomere-length↔mortality cohorts (association only, contested).
5Animal lifespan studyLifespan change in an animal model, e.g. AAV-TERT telomerase gene therapy in mice (delayed aging, increased longevity, no rise in cancer).
6Animal healthspan / disease-model / mechanismHealthspan, function, or disease-model change in an animal (e.g. telomerase gene therapy in a mouse pulmonary-fibrosis model); no whole-organism lifespan endpoint.
7In vitro / mechanismCell-culture or biochemical mechanism (telomerase enzymology, shelterin, T-loop, ALT); no whole-organism outcome.