Healthspan versus lifespan
The number of years matters. So does the possibility of doing something with an afternoon.
Function across a life
Healthspan is the part of a life spent in good function; lifespan measures its length. The distinction becomes tangible in the MOTS-c tests of running, grip strength and gait in old mice. Those measurements concern capability at the ages tested. A longer lifespan was outside that result.
A rally at a table-tennis table means getting into position, returning a ball and enjoying the next exchange. That picture is a personal preference about the purpose of a longer life. Neither peptide has been shown to preserve that afternoon in people.
Different survival outcomes in one experiment
The Epitalon experiment in female SHR mice measured several survival outcomes. Maximum lifespan increased 12.3%, and survival of the last 10% increased 13.3%, with mean lifespan unchanged. The figure below places those findings together; it is not a reconstructed survival curve.
The average and the extreme answer different questions. Publishing only the maximum would short-change this experiment. Equally, the unchanged mean does not erase the result among the longest-lived animals.
Human outcomes
The human evidence introduces a different problem. In the Epithalamin cohort, mortality was observed over six to eight years, but treatment was neither randomised nor placebo-controlled and the preparation was the parent extract. In the MOTS-c haemodialysis cohort, the researchers observed an association between an endogenous blood marker and later outcomes.
Human work needs to join the questions: can people retain useful function, for how long, with what adverse effects? The human record here has yet to answer that for administered synthetic Epitalon or MOTS-c. A convenient cell marker cannot do the human work by itself.
Time spent well
I'd want room in a longevity conversation for days that are ordinary and satisfying. It need not end in a sporting achievement, and useful function need not look the same in every life.
That is why the mouse movement experiment leads yolopeptide. It asks a concrete question that could matter during a life. The comparison page shows how much of that question each peptide's record has actually reached.