Study durations
How long did the experiments run?
Age, treatment duration and follow-up measure different kinds of time. Combining them can make a modest result sound enormous.
Reported observation periods
The word longevity tends to flatten these very different timings. The entries below describe exactly what was timed; they do not rank the compounds.
| Observation | Time reported | Context |
|---|---|---|
| Ipamorelin hormone peak | About 40 minutes | Acute intravenous study in healthy men |
| NR treatment | 8 weeks | Blood NAD+ in healthy overweight adults |
| NMN treatment | 60 days | Blood NAD+, walking and quality of life |
| GHK-mixture treatment | 6 months | Hair counts in men with hereditary hair loss |
| MOTS-c cohort follow-up | Median 26.5 months | Existing blood levels and later events in dialysis patients |
The last row has the longest human follow-up in this selection, yet nobody received MOTS-c. The additional time strengthens an observation about risk prediction; it supplies no treatment comparison.
Age at testing and time under treatment
Old mice in the MOTS-c physical-performance study were already old when tested. That gives the experiment an aging context. It does not turn a movement result into a lifespan result, or establish how long a human effect might persist.
Likewise, an ingredient having a history in cosmetics is a different matter from a person being followed under controlled treatment for years. The GHK-Cu page separates skin penetration, cosmetic studies and the six-month trial of a plain GHK mixture. I’m wary when any one of those clocks quietly takes the place of another.
Persistence and later health
At the end of the 10-week NMN trial, muscle insulin sensitivity had improved while body composition and HbA1c were unchanged. The useful result and the unchanged measures deserve equal space. Whether the improvement persists after treatment needs further observation.
For safety, rare events and slowly developing problems call for more than a brief comparison. For longevity, the question also includes illness, disability or survival. None of the studies here demonstrated extra years of human life. I’m prepared to wait for a measured outcome there. A projected benefit would settle nothing. The individual pages pursue the smaller, more answerable questions: MOTS-c, NAD+, GHK-Cu and ipamorelin.