Humanin (HN): Research, Mechanism & Current Evidence
First mitochondria-encoded peptide identified, discovered in Alzheimer's research and studied in ageing.
Also known as HN · MT-RNR2 · HNG (potent analogue)
What is Humanin?
Humanin is a peptide of 24 amino acids encoded within mitochondrial DNA. It was identified in 2001 from the surviving brain tissue of an Alzheimer's patient — researchers were looking for what protected those cells, and found this.
It was the first mitochondrial-derived peptide described, and opened the field that MOTS-c later joined.
What is Humanin researched for?
Neuroprotection, particularly against the toxicity of amyloid-beta in Alzheimer's models.
Ageing biology, including observations that circulating levels decline with age, and metabolic research on insulin sensitivity.
- Originally discovered for its ability to protect against amyloid-β toxicity in neuronal cells.
- Promotes mitochondrial biogenesis via PI3K/AKT signaling in PD models.
- Broad neuroprotective effects against various neurotoxic insults.
- Overexpression increases lifespan in C. elegans, dependent on daf-16/Foxo pathway.
- HNG analog improves metabolic healthspan parameters in middle-aged mice.
- Higher levels associated with longevity in centenarians and their offspring.
- Protects various cell types from stress-induced damage and death.
- Blocks pro-apoptotic proteins like Bax to prevent programmed cell death.
- Promotes mitochondrial function and biogenesis.
How does Humanin work?
Humanin is described as cytoprotective — it interferes with the process by which stressed cells commit to dying, known as apoptosis.
It has been reported to act both outside the cell, through a receptor complex involving gp130, and inside it, by binding proteins that trigger cell death.
What does the research show?
Cell-culture and rodent studies are the substance of the evidence, reporting protection against amyloid toxicity and improvements in insulin sensitivity.
Human research is observational: measuring circulating humanin in relation to age, disease and longevity, rather than administering it.
Limitations of the current evidence
There are no human intervention trials. The synthetic analogue HNG used in much of the research is considerably more potent than natural humanin and is a different molecule.
Observational associations between circulating levels and healthy ageing cannot establish cause and effect.
References
The mitochondrial derived peptide humanin is a regulator of lifespan and healthspan Aging
2020
Humanin overexpression extends lifespan in C. elegans; HNG treatment improves metabolic healthspan in middle-aged mice; levels higher in centenarian offspring.
Animal study
Neuroprotective Action of Humanin and
Humanin Analogues Biology · 2023
Comprehensive review of humanin's neuroprotective effects in Alzheimer's and Parkinson's disease models.
Review or meta-analysis
Mitochondria-derived peptides in aging and healthspan
Journal of Clinical Investigation · 2022
Review of mitochondria-derived peptides including humanin and their roles in aging and metabolic health.
Original Discovery of Humanin Proceedings of the National Academy of
Sciences · 2001
Hashimoto et al. cloned humanin from Alzheimer's patient brain; demonstrated protection against amyloid-β toxicity.
Common questions
How is humanin different from the HNG analog?
HNG (with a glycine substitution at position 14) is approximately 1000-fold more potent than native humanin. Both work via the same mitochondrial pathways, but HNG requires much lower doses—typically 0.5-2mg versus 1-5mg for standard humanin.