Humanin vs Klotho
Two 'longevity proteins' whose biology is genuinely compelling and whose supplement market is entirely aspirational — neither has a validated way to actually raise your own levels.
Humanin
A genuine cytoprotective mitochondrial-derived peptide whose levels fall with age — but no randomized human trial shows that taking it does anything for people.
Full Humanin evidence reviewKlotho
The foundational biology is real and compelling — mice lacking klotho age rapidly, mice overexpressing it live longer — but there is no validated oral supplement that raises human klotho levels, so the entire human case is aspirational.
Full Klotho evidence reviewSide by side
| Humanin | Klotho | |
|---|---|---|
| Marketed for | Longevity, metabolic health | Longevity, cognitive and kidney health |
| Evidence grade | Preclinical / minimal | Preclinical / minimal |
| Family | Mitochondrial / longevity | mTOR & other |
| Key human source | Hashimoto, PNAS 2001 | Kuro-o 1997 founding mouse study, Nature |
marks a row where the two differ. Evidence grades come from our evidence matrix, which grades each molecule on the human data for the use it is marketed for.
Our verdict
Klotho's founding science is dramatic: mice lacking it age rapidly, mice overexpressing it live longer — but there's no oral supplement shown to raise human klotho levels, so 'klotho supplements' are selling a name, not the mechanism. Humanin is a genuine mitochondrial-derived peptide whose levels fall with age and which shows cytoprotective effects in cell models, but no randomized human trial shows that taking it does anything for people. Both pages exist mainly to explain real biology that has, so far, produced no real product.
Humanin fits if
You're interested in mitochondrial-signaling peptides specifically — same caveat: real mechanism, zero human outcome data behind anything sold under this name.
Klotho fits if
You're interested in the aging-clock biology specifically — read this as science, not as a shopping guide.