Overview
Humanin is a 24-amino acid peptide encoded within the 16S ribosomal RNA gene of mitochondrial DNA (mtDNA), making it the first identified member of a novel class of bioactive molecules now known as mitochondrial-derived peptides (MDPs). Discovered in 2001 by Nishimoto and colleagues while screening for factors that could protect neurons from Alzheimer's disease-associated amyloid beta toxicity, Humanin has since been recognized as an endogenous cytoprotective signal with implications far beyond neuroprotection.
Humanin's significance extends beyond its direct biological effects—its discovery fundamentally changed our understanding of the mitochondrial genome. Previously, mitochondrial DNA was thought to encode only 13 electron transport chain subunits, 2 rRNAs, and 22 tRNAs. Humanin revealed that mtDNA also encodes bioactive peptides that function as retrograde signals from mitochondria to the rest of the cell, communicating mitochondrial status to nuclear and cytoplasmic signaling networks.
Circulating Humanin levels decline significantly with age and correlate with multiple age-related diseases including Alzheimer's disease, type 2 diabetes, cardiovascular disease, and cancer. This age-related decline, combined with Humanin's broad cytoprotective effects, has positioned it as both a biomarker of biological aging and a potential therapeutic target for age-related disease prevention.
This guide reviews Humanin's unique biology as a mitochondrial-derived peptide, its cytoprotective mechanisms, the evidence linking it to aging and disease, and its potential therapeutic applications.
Quick facts
- Mechanism
- Mitochondrial-encoded peptide with broad cytoprotective signaling
- Primary use
- Cytoprotection & Neuroprotection
- Evidence
- moderate
- FDA
- Not approved
- Route
- Subcutaneous injection, intrathecal (research)
- Typical results
- Neuroprotective and metabolic effects demonstrated in preclinical models; declining levels correlate with aging
Chemical information
Humanin (C₁₁₉H₂₀₄N₃₄O₃₂S₂) is a longevity compound with a molecular weight of 2687.2 g/mol. Its structural characteristics underpin its biological activity in longevity and anti-aging research.
How Humanin works
Humanin exerts its cytoprotective effects through multiple receptor-mediated signaling pathways. It binds to the formyl peptide receptor-like 1 (FPRL1/FPR2) and a trimeric receptor complex composed of CNTFR (ciliary neurotrophic factor receptor), WSX-1 (IL-27 receptor alpha), and gp130. Activation of this trimeric receptor triggers JAK-STAT3 signaling, which upregulates anti-apoptotic genes including BCL-2 and MCL-1.
The neuroprotective activity of Humanin was its first identified function. The peptide protects neurons from amyloid beta (Aβ)-induced toxicity through both receptor-mediated signaling and direct interaction with Aβ oligomers. Humanin binds to Aβ and prevents its aggregation into toxic fibrils, while simultaneously activating survival signaling through STAT3 that counteracts Aβ-induced apoptotic cascades. This dual mechanism makes Humanin uniquely effective against Alzheimer's-related neuronal death.
Beyond neuroprotection, Humanin demonstrates significant metabolic regulatory functions. It enhances insulin sensitivity by activating AMPK signaling, reduces hepatic glucose output, and improves pancreatic beta-cell survival under glucotoxic conditions. In animal models of type 2 diabetes, Humanin administration improves glucose tolerance and reduces insulin resistance—effects that are independent of its neuroprotective actions.
Humanin also functions as an intracellular signaling molecule within mitochondria, where it interacts with IGFBP-3 (insulin-like growth factor binding protein 3) and BAX (BCL-2 associated X protein). By sequestering BAX, Humanin prevents mitochondrial outer membrane permeabilization and subsequent cytochrome c release—the critical triggering event in the intrinsic apoptotic pathway. This mitochondrial-level anti-apoptotic action represents a direct protective mechanism at the organelle of origin.
- STAT3 activation: Activates JAK-STAT3 via trimeric receptor (CNTFR/WSX-1/gp130) for anti-apoptotic signaling
- Aβ interaction: Directly binds amyloid beta to prevent toxic aggregation in Alzheimer's models
- BAX sequestration: Prevents mitochondrial apoptotic pathway by binding pro-apoptotic BAX protein
- AMPK activation: Enhances insulin sensitivity and metabolic function via AMP kinase
- Retrograde signaling: Communicates mitochondrial status to nuclear transcriptional programs
- Age-dependent decline: Circulating levels decrease ~40% per decade after age 40
Pharmacokinetics
| Parameter | Value | Significance |
|---|---|---|
| Endogenous levels (young) | ~1–2 ng/mL plasma | Baseline circulating levels in healthy young adults |
| Age-related decline | ~40% per decade after 40 | Significant depletion correlating with aging phenotypes |
| Half-life (S14G-HN) | ~30 minutes (estimated) | Rapidly cleared; S14G modification improves potency 1000-fold |
| Molecular weight | 2,687 g/mol | 24-amino acid peptide with moderate tissue penetration |
| CNS penetration | Limited via peripheral routes | Intrathecal or intranasal may be needed for CNS targets |
Dosing & administration
Humanin dosing varies by indication and individual factors. No FDA-approved dosing exists for this compound; protocols in the literature derive from limited clinical or preclinical data and practitioner experience.
Any use should be conducted under qualified medical supervision with appropriate monitoring of safety markers.
Important: These dosing ranges are not FDA-approved. Any use should be under qualified medical supervision.
Side effects & safety
Safety data for Humanin is primarily derived from preclinical studies and limited human data. Long-term effects in humans remain incompletely characterized.
Common
- • Limited human safety data (primarily preclinical studies)
- • Injection site reactions (assumed for peptide)
- • Potential for mild gastrointestinal effects
- • Theoretical immune modulation
Serious / potential risks
- • No formal human toxicology data available
- • Potential interference with normal apoptotic clearance of damaged cells
- • Unknown effects of supraphysiological Humanin levels
- • Theoretical concern about anti-apoptotic effects in pre-cancerous cells
Drug interactions
| Medication | Interaction | Recommendation |
|---|---|---|
| Insulin / Metformin | Humanin improves insulin sensitivity; potential additive glucose-lowering | Monitor blood glucose if combining with diabetes medications |
| IGFBP-3 targeting agents | Humanin interacts directly with IGFBP-3 | May alter IGFBP-3 ligand availability; monitor IGF axis |
| Anti-Alzheimer's drugs (memantine, donepezil) | Complementary neuroprotective mechanisms | Theoretical synergy; no clinical data on combinations |
Storage & handling
Lyophilized (powder)
- • Store at -20°C to 4°C (freezer or refrigerator)
- • Protect from light and moisture
- • Stable for 12–24 months when stored properly
- • Keep in original sealed container until reconstitution
Reconstituted solution
- • Refrigerate at 2–8°C after reconstitution
- • Use bacteriostatic water for multi-dose reconstitution
- • Typical stability: 14–28 days refrigerated
- • Do not freeze reconstituted solution
Cost & availability
| Source | Cost | Notes |
|---|---|---|
| Research peptide suppliers | $80–$150 per 1mg vial | Limited commercial availability; verify sequence and purity |
| Custom synthesis (S14G-HN analog) | $200–$500 | Enhanced analog with 1000x potency over native Humanin |
The bottom line
Humanin is a groundbreaking mitochondrial-derived peptide that revealed the mitochondrial genome as a source of bioactive signaling molecules. Its broad cytoprotective effects—spanning neuroprotection, metabolic regulation, and anti-apoptotic signaling—make it a compelling target for aging and disease research. However, human clinical data is absent, and translation from animal models to therapeutic application remains a significant challenge.
Best for
- • Researchers studying mitochondrial-derived peptides and retrograde signaling
- • Preclinical investigation of neuroprotective strategies for Alzheimer's disease
- • Longevity researchers studying biomarkers of biological aging
Not for
- • Human self-administration (no clinical safety data)
- • Those seeking well-validated therapeutic interventions
- • Individuals with active cancer (anti-apoptotic concerns)
- • Replacement for established Alzheimer's disease treatments
Related compounds
MOTS-c
Sister mitochondrial-derived peptide with metabolic/exercise mimetic effects
SS-31
Mitochondria-targeted peptide restoring ETC function
Epitalon
Anti-aging peptide targeting telomerase—complementary aging mechanism
NAD+
Essential coenzyme for mitochondrial function and sirtuin activation
Frequently asked questions
References
- [1] Hashimoto Y, Niikura T, Tajima H, et al.. A rescue factor abolishing neuronal cell death by a wide spectrum of familial Alzheimer's disease genes and Aβ. Proc Natl Acad Sci USA (2001). doi: 10.1073/pnas.101565998 PMID: 11114178
- [2] Lee C, Yen K, Cohen P.. Humanin: a harbinger of mitochondrial-derived peptides?. Trends Endocrinol Metab (2013). doi: 10.1016/j.tem.2013.01.005 PMID: 23415156
- [3] Yen K, Lee C, Mehta H, Cohen P.. The emerging role of the mitochondrial-derived peptide humanin in stress resistance. J Mol Endocrinol (2013). doi: 10.1530/JME-12-0203 PMID: 23232048
- [4] Muzumdar RH, Huffman DM, Atzmon G, et al.. Humanin: a novel central regulator of peripheral insulin action. PLoS One (2009). doi: 10.1371/journal.pone.0006334 PMID: 19623253
- [5] Conte M, Ostan R, Fabbri C, et al.. Human Aging and Longevity Are Characterized by High Levels of Mitokines. J Gerontol A Biol Sci Med Sci (2019). doi: 10.1093/gerona/gly153 PMID: 30016404