Head-to-head comparison
| Property | Humanin | MOTS-c |
|---|---|---|
| Category | Longevity | Longevity |
| Legal Status | Research Only | Research Only |
| Primary Route | subcutaneous | subcutaneous |
| Half-life | Unknown in humans; estimated 1-4 hours based on peptide class | ~4 hours (estimated) |
| Mol. Weight | 2,685.48 Da | 2,174.54 Da |
| Side Effects | Unknown in humans — no human safety data exists, Injection site reactions, Theoretical hypoglycemia risk given insulin-sensitizing effects | Injection site reactions, Mild GI discomfort, Fatigue (transient) |
Key differences
- Mechanism: Humanin activates JAK2/STAT3 and PI3K/Akt via the CNTFRalpha/WSX-1/gp130 receptor complex and directly inhibits pro-apoptotic Bax; MOTS-c activates AMPK to regulate glucose metabolism, insulin sensitivity, and fatty acid oxidation.
- Primary focus: Humanin is primarily studied for neuroprotection and cytoprotection, particularly blocking amyloid-beta toxicity; MOTS-c is primarily studied as a metabolic regulator and exercise mimetic.
- Mitochondrial origin: Humanin is encoded within the 16S rRNA gene of mitochondrial DNA; MOTS-c is encoded within the 12S rRNA gene of mitochondrial DNA.
- Evidence: Humanin has epidemiological data linking higher plasma levels to better cognitive aging outcomes and reduced Alzheimer's severity; MOTS-c has data showing higher levels in long-lived populations and increases during exercise.
- Dosing: Humanin research protocols use 2.5-5 mg/kg twice weekly (mouse data only); MOTS-c protocols use 5-10 mg subcutaneously 3-5 times weekly (extrapolated from animal studies).
- Side effects: Both have limited human safety data; humanin has theoretical hypoglycemia risk from insulin-sensitizing effects, while MOTS-c has mild injection site reactions and GI discomfort reported in community use.
- Legal status: Both are research-only compounds with no FDA-approved therapeutics and no completed human clinical trials.
The verdict
Humanin and MOTS-c represent complementary facets of mitochondrial-derived peptide biology. Humanin's strength lies in its cytoprotective and neuroprotective properties, with particularly relevant data in Alzheimer's disease models. MOTS-c's strength lies in its metabolic regulatory functions and its role as a potential exercise mimetic. Both decline with age and both show longevity associations, but neither has completed human clinical trials. Their different mechanisms suggest they may serve complementary rather than overlapping functions in aging biology.
Frequently asked questions
Both are mitochondrial-derived peptides with complementary mechanisms — humanin for cytoprotection and MOTS-c for metabolic regulation. They are often listed as stack partners in longevity protocols. No controlled studies have evaluated this combination in any species.
Mitochondrial-derived peptides (MDPs) are small peptides encoded within the mitochondrial genome, which was previously thought to encode only 13 proteins and ribosomal components. Humanin (from the 16S rRNA gene) and MOTS-c (from the 12S rRNA gene) are the two most studied MDPs and represent a relatively new class of signaling molecules.
Humanin has more direct evidence for neuroprotection. It was first identified from Alzheimer's brain tissue, blocks amyloid-beta-induced apoptosis, and has epidemiological data showing reduced CSF levels in Alzheimer's patients. MOTS-c's metabolic benefits may indirectly support brain health, but its primary research focus has been on metabolic and exercise-related outcomes.
Yes, both peptides decline with age, which is consistent with the broader decline in mitochondrial function during aging. This age-related decline has been proposed as a contributor to metabolic dysfunction and neurodegeneration. Studies show higher circulating levels of both peptides in long-lived populations.
Neither humanin nor MOTS-c has FDA-approved therapeutics or completed human clinical trials as of 2026. Both are available from research peptide suppliers for laboratory use only. All dosing protocols used in community settings are extrapolated from animal study data.