Two caveats govern every page on this site. (1) Telomere length is a contested aging biomarker — it is measured differently by different methods, varies between tissues, and "longer" is not straightforwardly "healthier"; changing a telomere-length or telomerase-activity number in a trial is not the same as slowing human aging. (2) Activating telomerase is not risk-free — telomerase is silenced in most somatic cells and reactivated in most cancers, so its activation raises an unresolved cancer-risk question. Tellingly, the only FDA-approved telomerase drug — imetelstat (RYTELO, 2024) — inhibits telomerase to treat cancer (lower-risk MDS), the opposite direction from the anti-aging "activation" narrative.
○ Evidence tier 2 — Human clinical-outcome RCT — disease population

Record

DesignProspective clinical trial of nandrolone in telomeropathies (ASH 2019 abstract)
DOI10.1182/blood-2019-130844
Citation statusdoi verified via Crossref 2026-07-12 (Blood 2019;134(Supplement_1):2501, Clé DV, Catto LF, ..., Calado RT, 'Telomere Elongation and Clinical Improvement in Telomeropathy Patients: A Prospective Clinical Trial of Nandrolone in Telomeropathies'). NOTE: this is an ASH annual-meeting abstract (Blood supplement), not a full peer-reviewed paper — no full paper published — the ASH/Blood abstract is the primary record.

Five-qualifier claim

Species / populationPatients with telomeropathies (inherited telomere-biology disorders) — a rare DISEASE population.
Exposure, route, scheduleNandrolone (an anabolic androgen) in a prospective clinical trial in telomeropathies.
Comparator / durationProspective clinical trial (single-arm) with telomere-length and clinical endpoints.
Endpoint / numeric resultReported telomere elongation and clinical improvement in treated telomeropathy patients — consistent with androgen upregulation of telomerase.
What it did NOT establishA rare-disease result (and reported as a conference abstract, not a full journal paper). It is not healthy aging and not a lifespan outcome; androgen toxicity applies.

Interventions

Primary reference

https://doi.org/10.1182/blood-2019-130844

Exact identifier confirmed against the primary record via Crossref/ClinicalTrials.gov where stated in the citation status; anything marked needs_primary_fulltext is not yet confirmed.