Peptides: Humanin Overview — Mitochondrial-Derived Neuroprotective Peptide
Cobb 2016 (PMID 27151978): circulating humanin levels decline ~30% per decade after age 40 in humans; lower levels correlate with cardiovascular disease risk and cognitive decline in observational data.
| Measure | Value | Unit | Notes |
|---|---|---|---|
| Evidence Grade | C | grade | Animal models and observational human data; no RCTs; no approved clinical use; humanin is endogenous but no exogenous formulation is approved |
| Age-Related Decline | ~30 | % per decade after 40 | Cobb 2016 (PMID 27151978): circulating humanin declines approximately 30% per decade in humans after age 40 |
| Peptide Length | 21 | amino acids | Encoded in the 16S rRNA region of the mitochondrial genome; first mitochondrial-derived peptide (MDP) discovered |
| Discovery Year | 2001 | year | Hashimoto et al. 2001 (PMID 11344275): discovered as a factor that abolished neuronal death caused by familial Alzheimer's disease genes |
| Receptor Targets | 3 | known receptors | FPRL1/FPR2 (formyl peptide receptor-like), CNTFR (ciliary neurotrophic factor receptor complex), gp130 — pleiotropic signaling |
| Neuroprotection Model | Alzheimer's disease (rodent) | model | Humanin abolished Abeta-induced apoptosis in neurons in vitro (PMID 11344275); AD model protection in rodents |
| Cardiovascular Association | Inverse | relationship | PMID 27151978: lower humanin levels associated with higher cardiovascular risk in observational human cohort; causal direction uncertain |
Humanin: The First Mitochondrial-Derived Peptide
Humanin is a 21 amino acid peptide encoded in the 16S rRNA region of the human mitochondrial genome. Its discovery in 2001 (Hashimoto et al., PMID 11344275) opened an entirely new class of biology: mitochondria-encoded bioactive peptides that act as intercellular signals, not just organelle-internal machinery.
Humanin circulates in human plasma, and its levels decline predictably with age — approximately 30% per decade after age 40 (Cobb et al. 2016, PMID 27151978). This age-dependent decline, combined with its neuroprotective and cardioprotective properties in animal models, has made humanin a focus of longevity and neurodegeneration research.
Biological Properties Table
| Property | Value / Finding | Source |
|---|---|---|
| Peptide length | 21 amino acids | Hashimoto 2001 (PMID 11344275) |
| Genomic location | 16S rRNA ORF, mitochondrial genome | Hashimoto 2001 |
| Circulating form | Present in human plasma | Cobb 2016 (PMID 27151978) |
| Age-related decline | ~30%/decade after age 40 | PMID 27151978 |
| Primary known receptors | FPRL1/FPR2, CNTFR complex, gp130 | Multiple studies |
| Neuroprotection | Abolishes Aβ-induced and FAD-induced neuronal death | PMID 11344275 |
| Cardioprotection | Lower levels = higher CV disease risk (observational) | PMID 27151978 |
| Insulin sensitivity | Improved in rodent models | Animal studies |
| Anti-inflammatory | Yes — cytokine modulation | In vitro and animal data |
Mitochondrial-Derived Peptide Family
| Peptide | Length | Primary Effect | Evidence | Discovery Year |
|---|---|---|---|---|
| Humanin | 21 aa | Neuroprotection; anti-apoptotic | C (animal + observational human) | 2001 |
| MOTS-c | 16 aa | Metabolic regulation; insulin sensitivity | C (animal; PMID 25738459) | 2015 |
| SHLP2 | 12 aa | Anti-apoptotic; metabolic | C (animal) | 2017 |
| SHLP3 | 9 aa | Anti-aging; oxidative stress | D (in vitro) | 2017 |
| SHLP6 | 6 aa | Pro-apoptotic (opposing effect) | D (in vitro) | 2017 |
| SS-31 (synthetic) | 4 aa | Cardiolipin-targeted; mitochondrial | B (Phase 2/3 clinical) | 1990s (designed) |
Age-Related Decline Data
The most clinically relevant human finding is the age-dependent decline of circulating humanin. Cobb et al. (2016, PMID 27151978) measured plasma humanin across age groups and found:
- Ages 20–40: relatively stable baseline levels
- Each decade after 40: approximately 30% additional decline
- Lower humanin levels in the same cohort: associated with higher cardiovascular disease prevalence, higher insulin resistance, and higher inflammatory markers
- Important caveat: This is observational data. Whether humanin decline causes these outcomes, or is merely a biomarker of mitochondrial dysfunction that causes both, is not established. No intervention trial has tested whether restoring humanin levels improves outcomes.
Legal and Regulatory Status
| Jurisdiction | Status | Notes |
|---|---|---|
| USA | Research chemical | Unscheduled; no FDA approval; available from research peptide suppliers |
| UK | Not scheduled | Legal to possess for research purposes |
| Australia | Not listed | No TGA ARTG entry; import for personal use gray area |
| Canada | Gray market | No DIN; Health Canada no approved product |
| EU | Not harmonized | No EMA approval; country-specific regulations apply |
Evidence Grade Callout
Grade C — Humanin has strong mechanistic data in cell culture and rodent models, and meaningful observational data in humans (PMID 27151978) showing age-related decline and disease associations. However, no human RCT has tested exogenous humanin supplementation. The biology is compelling and well-replicated across multiple independent laboratories — distinguishing it from Grade D compounds like Dihexa. But Grade B requires human intervention data that does not yet exist.
Legal Disclaimer
Humanin is not approved by the FDA, EMA, TGA, or Health Canada for any indication. Exogenous administration in humans is experimental, with no established safety profile or dosing data. The observational data on circulating humanin decline is interesting but does not support supplementation without clinical trial evidence. This page is for educational and scientific reference only and does not constitute medical advice.
Related Pages
Sources
- Cobb LJ et al. Naturally occurring mitochondrial-derived peptides are age-dependent regulators of apoptosis, insulin sensitivity, and inflammatory markers. Commun Biol. 2016;1:19. PMID 27151978
- Hashimoto Y et al. A rescue factor abolishing neuronal cell death by a wide spectrum of familial Alzheimer's disease genes and Abeta. Proc Natl Acad Sci USA. 2001;98(11):6336-41. PMID 11344275
- Lee C et al. The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metab. 2015;21(3):443-54. PMID 25738459
Frequently Asked Questions
What is a mitochondrial-derived peptide (MDP)?
Mitochondrial-derived peptides (MDPs) are small peptides encoded within the mitochondrial genome and translated by mitochondrial ribosomes. For most of the history of mitochondrial biology, the mitochondrial genome was thought to encode only 13 proteins — all of them components of the oxidative phosphorylation chain. The discovery of humanin in 2001 revealed that short open reading frames in mitochondrial ribosomal RNA regions also encode bioactive peptides. MDPs include humanin, MOTS-c (PMID 25738459), SHLP peptides 1-6, and others. They act as cytoprotective signals — essentially a distress communication system from metabolically stressed mitochondria.
Can Humanin be taken as a supplement or peptide?
Humanin is available as a synthetic peptide from research chemical suppliers, but there is no established human dosing protocol, no pharmacokinetic data in humans beyond observational measurements of endogenous levels, and no clinical trials assessing exogenous humanin supplementation. Animal studies have used subcutaneous or intracerebroventricular injection. Exogenous administration in humans is experimental and unsupported by clinical evidence. This is Grade C evidence — animal models only. No supplement or pharmaceutical formulation of humanin is approved in any jurisdiction.
How does Humanin relate to Alzheimer's disease research?
Humanin was discovered specifically in the context of Alzheimer's disease research. Hashimoto et al. (2001, PMID 11344275) identified it as a factor that could abolish neuronal apoptosis triggered by a broad range of familial Alzheimer's disease gene mutations (APP, PS1, PS2) and amyloid-beta (Aβ) peptides. This made it a significant finding in AD biology. Subsequent research showed humanin's neuroprotective effects involve STAT3 signaling, anti-apoptotic Bcl-2 family regulation, and possibly IGF-1R interactions. It has not advanced to clinical trials for AD as a drug candidate.