Humanin (10mg)

Humanin (HN, 10mg): A 24-Amino-Acid Mitochondria-Derived Peptide (MDP) Encoded within the Mitochondrial 16S Ribosomal RNA Gene (MT-RNR2 / MTRNR2L Family), with the Sequence MAPRGFSCLLLLTSEIDLPVKRRA — Discovered in 2001 as a Neuronal Survival Factor in Alzheimer's Disease Brain Tissue, with Potent Anti-Apoptotic, Neuroprotective, Cytoprotective, Metabolic, Anti-Inflammatory, and Anti-Aging Properties — the 10mg Vial Format for Investigational Research in Neurodegeneration, Mitochondrial Dysfunction, Apoptosis, Metabolic Health, Cardiovascular Protection, and Longevity

Humanin (HN) is a 24-amino-acid peptide with the amino acid sequence MAPRGFSCLLLLTSEIDLPVKRRA (methionine-alanine-proline-arginine-glycine-phenylalanine-serine-cysteine-leucine-leucine-leucine-leucine-threonine-serine-glutamic acid-isoleucine-aspartic acid-leucine-proline-valine-lysine-arginine-arginine-alanine), with a molecular weight of approximately 2.68 kDa (2,684 Daltons). Humanin is a member of a unique and fascinating class of peptides known as mitochondria-derived peptides (MDPs) — peptides that are encoded within the mitochondrial genome (rather than the nuclear genome) and translated within mitochondria, representing a previously unrecognized layer of mitochondrial gene expression and inter-organellar signaling. Humanin was the first MDP to be discovered, and its discovery in 2001 by the Nishimoto laboratory (at the University of California, Los Angeles) opened an entirely new field of research into mitochondrial peptides and their biological roles. The story of humanin's discovery is particularly compelling: in 2001, Hashimoto and colleagues were investigating the molecular basis of Alzheimer's disease (AD) by studying brain tissue from patients with familial Alzheimer's disease (FAD) — specifically, they were trying to understand why some neurons in the AD brain survive while others die. They used a cDNA library from the occipital lobe of an AD patient (a brain region relatively spared in AD, compared to the hippocampus and cortex which are severely affected) and screened for factors that could protect neurons from death induced by FAD-associated mutant genes (such as mutant amyloid precursor protein [APP] and presenilin-1 [PS1]). This screen led to the identification of a novel 24-amino-acid peptide that they named "Humanin" (from "human" + "in," following the naming convention of other peptides like insulin, ghrelin, etc.), which was found to be encoded within the mitochondrial 16S ribosomal RNA gene (MT-RNR2, also known as RNR2, located in the mitochondrial DNA at positions 1671-3229). This was a remarkable discovery because the mitochondrial genome was previously thought to encode only 13 proteins (all components of the oxidative phosphorylation system), 2 ribosomal RNAs (12S and 16S rRNA), and 22 transfer RNAs — the idea that a peptide could be encoded within a ribosomal RNA gene and translated was unprecedented and challenged existing dogma about mitochondrial gene expression. Subsequent research revealed that humanin is not an isolated curiosity: multiple other mitochondria-derived peptides have since been discovered, including MOTS-c (mitochondrial open reading frame of the 12S rRNA-c, discovered in 2015, a 16-amino-acid peptide encoded within the 12S rRNA gene), humanin-like peptides (encoded by nuclear MTRNR2L genes — MTRNR2L1 through MTRNR2L12, which are nuclear homologs of the mitochondrial MT-RNR2 gene, some of which may encode functional peptides), and other putative MDPs, suggesting that mitochondrial peptide signaling is a widespread and biologically important phenomenon. Humanin's biological effects are remarkably diverse and potent, and it has been described as a "survival peptide," "neuroprotective factor," "mitochondrial hormone," and "longevity peptide" due to its broad range of cytoprotective and homeostatic effects. The key biological properties of humanin include: (1) Potent anti-apoptotic (anti-cell death) effects — humanin was originally discovered for its ability to protect neurons from apoptosis induced by Alzheimer's disease-related insults (mutant APP, mutant PS1, amyloid-beta [Aβ] toxicity), and subsequent research has shown that humanin protects a wide variety of cell types (neurons, cardiomyocytes, pancreatic beta cells, endothelial cells, hepatocytes, renal cells, retinal cells, immune cells) from apoptosis induced by diverse stressors including oxidative stress, endoplasmic reticulum (ER) stress, mitochondrial dysfunction, excitotoxicity, serum deprivation, chemotherapy, ischemia-reperfusion injury, and inflammatory cytokines; (2) Neuroprotective effects — humanin protects neurons from a wide range of neurotoxic insults including amyloid-beta (Aβ) toxicity, tau hyperphosphorylation, excitotoxicity (glutamate toxicity), oxidative stress, mitochondrial dysfunction, ER stress, ischemia, and neuroinflammation; humanin has shown beneficial effects in animal models of Alzheimer's disease (reduced Aβ accumulation, reduced tau pathology, improved cognitive function, reduced neuronal loss), Parkinson's disease (protected dopaminergic neurons, reduced neuroinflammation, improved motor function), stroke (reduced infarct volume, improved neurological function), Huntington's disease, amyotrophic lateral sclerosis (ALS), traumatic brain injury, and peripheral neuropathy; (3) Mitochondrial protective effects — as a mitochondria-derived peptide, humanin plays a key role in mitochondrial homeostasis: it improves mitochondrial function (increased ATP production, improved mitochondrial respiration, increased mitochondrial membrane potential), reduces mitochondrial reactive oxygen species (ROS) production, increases mitochondrial antioxidant capacity (increased SOD, catalase, glutathione), inhibits mitochondrial permeability transition pore (mPTP) opening (which is a key event in mitochondria-mediated apoptosis), promotes mitochondrial biogenesis (via PGC-1α, NRF-1, TFAM), and regulates mitophagy (selective removal of damaged mitochondria via autophagy); (4) Metabolic effects — humanin has significant effects on glucose and lipid metabolism: it improves insulin sensitivity and glucose tolerance (in animal models of insulin resistance and type 2 diabetes), increases glucose uptake in muscle and adipose tissue (via AMPK activation and GLUT4 translocation), reduces hepatic glucose production, improves pancreatic beta cell survival and function (protecting beta cells from apoptosis, increasing glucose-stimulated insulin secretion), reduces body weight and fat mass (in some models, through increased energy expenditure and fat oxidation), improves lipid profile (reduced triglycerides, LDL, total cholesterol, increased HDL in some studies), and has been proposed as a potential therapeutic for metabolic syndrome, type 2 diabetes, obesity, and non-alcoholic fatty liver disease (NAFLD/NASH); circulating humanin levels have been found to be reduced in patients with type 2 diabetes, obesity, metabolic syndrome, and cardiovascular disease, and lower humanin levels are associated with worse metabolic health; (5) Cardiovascular protective effects — humanin protects the cardiovascular system through multiple mechanisms: it protects cardiomyocytes from apoptosis and ischemia-reperfusion injury (reduced infarct size, improved cardiac function), improves endothelial function (increased nitric oxide [NO] production via eNOS activation, reduced endothelial dysfunction, reduced vascular inflammation), inhibits vascular smooth muscle cell proliferation and migration (potentially reducing atherosclerosis and restenosis after angioplasty), reduces atherosclerotic plaque formation (reduced lipid accumulation, reduced inflammation, increased plaque stability), reduces cardiac fibrosis (inhibited cardiac fibroblast proliferation and collagen deposition), protects against heart failure (improved cardiac function, reduced cardiac remodeling, reduced cardiomyocyte apoptosis), and has beneficial effects on hypertension (reduced blood pressure in some models via improved endothelial function and vasodilation); humanin levels are reduced in patients with coronary artery disease, heart failure, and hypertension, and lower humanin levels are associated with worse cardiovascular outcomes; (6) Anti-inflammatory effects — humanin modulates immune and inflammatory responses: it inhibits pro-inflammatory cytokine production (TNF-α, IL-1β, IL-6, IFN-γ) from immune cells (macrophages, monocytes, T cells), reduces inflammatory cell infiltration into tissues, inhibits NF-κB signaling (a master regulator of inflammation), promotes anti-inflammatory cytokine production (IL-10, TGF-β), modulates immune cell polarization (promotes M2 anti-inflammatory macrophage polarization over M1 pro-inflammatory polarization), and has shown beneficial effects in animal models of inflammatory diseases including rheumatoid arthritis, inflammatory bowel disease (IBD), sepsis, and neuroinflammation; (7) Anti-aging / longevity effects — humanin has emerged as a potential longevity factor: circulating humanin levels decline with age in humans and animal models (similar to other longevity-associated factors like growth hormone, IGF-1, DHEA, melatonin), and higher humanin levels are associated with longer lifespan in some animal models; humanin's anti-aging effects are thought to be mediated through its combined effects on mitochondrial function (improved mitochondrial respiration, reduced ROS, increased mitophagy), apoptosis inhibition (reduced age-related cell loss), metabolic health (improved insulin sensitivity, reduced fat accumulation), inflammation reduction (chronic low-grade inflammation / "inflammaging" is a hallmark of aging), oxidative stress reduction, proteostasis maintenance (reduced protein misfolding and aggregation), and stem cell protection; humanin has been shown to extend lifespan in C. elegans (the nematode worm, a common aging model) and has shown beneficial effects on age-related phenotypes in mouse models; the age-related decline in humanin has led to the hypothesis that humanin supplementation or upregulation could be a potential anti-aging intervention, although this remains an active area of investigation; (8) Other effects — humanin has also been reported to have effects on bone health (promotes osteoblast differentiation, inhibits osteoclast formation, may improve bone density), reproductive health (protects testicular cells, improves sperm quality, may have effects on ovarian function), eye health (protects retinal cells, may be beneficial in glaucoma, macular degeneration, diabetic retinopathy), skin health (protects skin cells from UV damage and oxidative stress, may have anti-aging effects on skin), and cancer (complex and context-dependent — humanin can protect normal cells from chemotherapy-induced damage, but may also protect cancer cells from apoptosis; the role of humanin in cancer is complex and requires further investigation — some studies suggest humanin may have anti-tumor effects in certain contexts, while others suggest it may promote cancer cell survival). The molecular mechanisms by which humanin exerts these diverse effects are complex and involve multiple signaling pathways and molecular targets. Humanin is thought to act through both extracellular (receptor-mediated) and intracellular (direct mitochondrial/cytosolic) mechanisms: (1) Extracellular receptor-mediated signaling — humanin can be secreted from cells and act as a hormone/cytokine, binding to cell surface receptors to initiate signaling cascades. The best-characterized humanin receptor is the CNTF receptor complex (ciliary neurotrophic factor receptor complex, consisting of CNTFRα, LIFRβ, and gp130) — humanin binds to this receptor complex (with CNTFRα as the ligand-binding subunit, and LIFRβ/gp130 as signal-transducing subunits), activating downstream signaling pathways including JAK2-STAT3 (janus kinase 2 - signal transducer and activator of transcription 3), MAPK/ERK, and PI3K/Akt. The JAK2-STAT3 pathway is particularly important for many of humanin's neuroprotective and anti-inflammatory effects: activated STAT3 translocates to the nucleus and regulates genes involved in cell survival (Bcl-2, Bcl-xL), antioxidant defense (SOD, catalase), and inflammation (inhibition of pro-inflammatory cytokines). Humanin has also been reported to interact with other receptors including the formyl peptide receptor-like 1 (FPRL1, also known as FPR2) — a G-protein-coupled receptor involved in inflammation and immune responses — and possibly other as-yet-unidentified receptors; (2) Intracellular / mitochondrial mechanisms — as a mitochondria-derived peptide, humanin is also present within mitochondria and the cytosol, where it can directly interact with intracellular targets. One of the best-characterized intracellular mechanisms is humanin's interaction with insulin-like growth factor binding protein 3 (IGFBP-3) — humanin binds to IGFBP-3 and modulates its effects (IGFBP-3 can have both IGF-dependent and IGF-independent effects, including pro-apoptotic effects in some contexts, and humanin may counteract these pro-apoptotic effects). Humanin also directly interacts with and inhibits the Bax protein (a pro-apoptotic Bcl-2 family member that translocates to mitochondria during apoptosis, causing mitochondrial outer membrane permeabilization [MOMP] and release of cytochrome c, which activates the caspase cascade) — humanin binds to Bax and prevents its mitochondrial translocation and activation, thereby inhibiting mitochondria-mediated apoptosis. Humanin also modulates mitochondrial function directly: it inhibits the mitochondrial permeability transition pore (mPTP), improves mitochondrial respiration and ATP production, reduces mitochondrial ROS, and promotes mitochondrial biogenesis and mitophagy. Other intracellular mechanisms include modulation of the AMPK pathway (AMP-activated protein kinase — a master regulator of cellular energy homeostasis; humanin activates AMPK, which leads to increased glucose uptake, increased fatty acid oxidation, increased mitochondrial biogenesis via PGC-1α, and reduced inflammation), the PI3K/Akt pathway (protein kinase B — activated by humanin via receptor-mediated signaling, leading to increased cell survival via Bad/caspase-9 inhibition, increased protein synthesis via mTOR, increased glucose uptake via GLUT4), the MAPK/ERK pathway (cell proliferation, differentiation, survival), the NF-κB pathway (inflammation — humanin inhibits NF-κB activation, reducing pro-inflammatory gene expression), and the Nrf2 pathway (nuclear factor erythroid 2-related factor 2 — a master regulator of antioxidant response; humanin activates Nrf2, leading to increased expression of antioxidant and cytoprotective genes including HO-1, NQO1, SOD, catalase, glutathione). The 10mg vial format of research-grade humanin provides a convenient, pre-measured dose suitable for a range of investigational applications. Humanin is typically administered by subcutaneous, intramuscular, or intravenous injection, or can be used in in vitro cell culture studies. Typical research doses for in vivo studies range from 0.1-5 mg/kg per day (depending on the species, route of administration, and research application), with a 10mg vial providing sufficient material for multiple doses or in vitro experiments. For in vitro cell culture studies, humanin is typically used at concentrations ranging from 10 nM to 100 μM (with 1-10 μM being commonly used for cytoprotection studies), and a 10mg vial (2.68 kDa) provides approximately 3.73 micromoles of peptide, sufficient for numerous cell culture experiments. Reconstitution: add 1-5 mL of bacteriostatic water (or sterile water for in vitro use / IV administration) to yield 10-2 mg/mL; for example, adding 2 mL yields 5 mg/mL (5,000 μg/mL, ~1.86 mM), so a 100 μg dose = 0.02 mL, 500 μg = 0.1 mL, 1 mg = 0.2 mL, 5 mg = 1.0 mL, 10 mg = 2.0 mL. Reconstituted humanin is stable for 14-30 days when refrigerated at 4°C and protected from light; the lyophilized powder is stable for 24 months from manufacture when stored at -20°C, protected from light and moisture. The safety profile of humanin is generally favorable for research use, with few reported side effects in animal studies even at relatively high doses — humanin has been described as having a wide therapeutic index. Common considerations include: injection site reactions (mild pain, erythema, swelling), possible transient flushing or warmth (due to vasodilatory effects), possible effects on glucose metabolism (humanin generally improves insulin sensitivity and glucose tolerance, but individual responses may vary — monitor glucose in diabetic individuals), possible effects on blood pressure (humanin may have mild vasodilatory/antihypertensive effects — monitor blood pressure in hypotensive individuals), possible immune modulation (humanin has anti-inflammatory effects — theoretically could affect immune responses, although this has not been reported as a significant issue in studies), and possible effects on cancer (complex and context-dependent — humanin can protect normal cells from damage, but may also protect cancer cells; individuals with active malignancy should use caution). Contraindications include: known hypersensitivity to humanin or any component, pregnancy and breastfeeding (insufficient safety data), and active malignancy (due to the theoretical potential for humanin to protect cancer cells from apoptosis — although this is context-dependent and requires further investigation). As of 2026, humanin is NOT approved by the FDA or other major regulatory agencies for any clinical indication — it remains an investigational research compound, although it has been extensively studied in preclinical models and has shown promising therapeutic potential for a wide range of age-related and metabolic diseases. The research-grade humanin supplied by Amideworks is intended for laboratory and investigational use only, not for human consumption or therapeutic use^{[1][2][3][4][5][6][7][8][9][10]}.

The Science of Humanin: Mitochondrial Origins, Multi-Target Mechanisms, and the Emerging Role of Mitochondria-Derived Peptides in Health and Disease

Humanin occupies a unique position in the landscape of bioactive peptides: it is not a classical peptide hormone encoded by a nuclear gene and processed through the secretory pathway, but rather a mitochondria-derived peptide (MDP) encoded within the mitochondrial ribosomal RNA gene and translated within mitochondria. This unusual origin has profound implications for our understanding of mitochondrial biology, inter-organellar signaling, and the evolution of peptide hormones, and it positions humanin at the intersection of several major research areas: mitochondrial dysfunction (a hallmark of aging and many diseases), apoptosis (programmed cell death, dysregulated in cancer, neurodegeneration, and autoimmune disease), metabolism (obesity, diabetes, metabolic syndrome), inflammation (chronic low-grade inflammation in aging and chronic disease), and longevity (the search for interventions that extend healthy lifespan). To fully appreciate humanin's significance, it is necessary to understand its mitochondrial origins, the complex multi-target mechanisms through which it exerts its effects, and the broader context of mitochondria-derived peptides as a newly recognized class of signaling molecules. The mitochondrial origins of humanin represent a paradigm shift in our understanding of the mitochondrial genome. Mitochondria are semi-autonomous organelles of endosymbiotic origin (descended from α-proteobacteria that were engulfed by ancestral eukaryotic cells approximately 1.5-2 billion years ago), and they retain their own circular double-stranded DNA genome (mitochondrial DNA, mtDNA). The human mitochondrial genome is 16,569 base pairs in length and was the first complete human genome to be sequenced (in 1981 by Anderson et al.). For decades, the mitochondrial genome was thought to encode a fixed and limited set of gene products: 13 protein-coding genes (all subunits of the oxidative phosphorylation [OXPHOS] system — complexes I, III, IV, and ATP synthase; notably, complex II [succinate dehydrogenase] is entirely nuclear-encoded), 2 ribosomal RNA genes (12S rRNA [MT-RNR1] and 16S rRNA [MT-RNR2], which are structural components of the mitochondrial ribosome), and 22 transfer RNA genes (required for mitochondrial protein synthesis). This "13+2+22" model of mitochondrial gene expression was considered complete and well-established, and the idea that additional functional peptides could be encoded within the mitochondrial genome — particularly within non-protein-coding regions like ribosomal RNA genes — was not seriously considered. The discovery of humanin in 2001 challenged this dogma: Hashimoto and colleagues found that the 24-amino-acid humanin peptide was encoded within the mitochondrial 16S ribosomal RNA gene (MT-RNR2), specifically within a region that was previously thought to be purely structural rRNA with no protein-coding potential. This was surprising because: (1) the mitochondrial genetic code differs from the universal nuclear code (in human mitochondria, UGA codes for tryptophan instead of stop, AUA codes for methionine instead of isoleucine, AGA and AGG code for stop instead of arginine), and the humanin open reading frame (ORF) uses the mitochondrial genetic code; (2) the 16S rRNA gene was thought to be transcribed exclusively as a structural rRNA, not as a mRNA that could be translated into a peptide; (3) mitochondrial translation was thought to be exclusively dedicated to the 13 OXPHOS proteins, with no "extra" peptides being produced. Subsequent research confirmed that humanin is indeed translated within mitochondria (using the mitochondrial translation machinery, including mitochondrial ribosomes [mitoribosomes], mitochondrial tRNAs, and mitochondrial translation factors), and that it can be exported from mitochondria to the cytosol and even secreted from cells to act in an endocrine/paracrine manner. The discovery of humanin was followed by the discovery of other mitochondria-derived peptides, most notably MOTS-c (mitochondrial open reading frame of the 12S rRNA-c, a 16-amino-acid peptide encoded within the 12S rRNA gene [MT-RNR1], discovered in 2015 by the Lee laboratory at USC), which has been shown to have significant metabolic effects (improving insulin sensitivity, glucose tolerance, and exercise capacity, and has been described as an "exercise mimetic" and "metabolic regulator"). In addition to the mitochondrial MT-RNR2 gene, the nuclear genome contains a family of humanin-like genes (MTRNR2L genes) — MTRNR2L1 through MTRNR2L12 (also known as HN1-HN12, or humanin-like 1-12) — which are nuclear homologs of the mitochondrial MT-RNR2 gene, likely arising from historical insertions of mitochondrial DNA into the nuclear genome (nuclear mitochondrial DNA segments, or NUMTs). Some of these nuclear MTRNR2L genes may encode functional humanin-like peptides (although this is still under investigation — some may be pseudogenes, while others may produce functional peptides), and they may represent an additional layer of humanin biology. The discovery of mitochondria-derived peptides has opened an entirely new field of research and has fundamentally changed our understanding of the mitochondrial genome: it is now recognized that the mitochondrial genome encodes more than just the classical 13+2+22 products, and that mitochondrial peptides may play important roles in inter-organellar signaling, cellular homeostasis, and disease. It has been estimated that there may be dozens or even hundreds of as-yet-undiscovered small open reading frames (sORFs) within the mitochondrial genome that could encode functional peptides, making this an active and exciting area of investigation. The molecular mechanisms of humanin are remarkably complex and involve multiple signaling pathways, molecular targets, and subcellular locations. Humanin is unusual in that it appears to act through both extracellular (receptor-mediated, endocrine/paracrine) and intracellular (mitochondrial, cytosolic) mechanisms, and it interacts with a diverse array of molecular targets. This multi-target, multi-compartment mechanism likely explains humanin's extraordinarily broad range of biological effects — it is not a highly specific ligand for a single receptor, but rather a pleiotropic cytoprotective peptide that acts at multiple nodes in cellular stress and survival pathways. The major mechanisms can be organized as follows:

1. Extracellular receptor-mediated signaling — the CNTF receptor complex and JAK2-STAT3 pathway: The best-characterized mechanism of humanin action is through binding to the ciliary neurotrophic factor (CNTF) receptor complex, which consists of three subunits: CNTFRα (the ligand-binding α-subunit, which is GPI-anchored to the cell membrane and provides ligand specificity), LIFRβ (leukemia inhibitory factor receptor β, a signal-transducing β-subunit), and gp130 (a common signal-transducing subunit shared by many cytokines in the IL-6 family). Humanin binds to this receptor complex (with CNTFRα as the primary ligand-binding subunit), inducing dimerization/oligomerization of LIFRβ and gp130, which brings their intracellular domains into close proximity and activates the constitutively associated JAK2 (janus kinase 2) tyrosine kinases through trans-phosphorylation. Activated JAK2 then phosphorylates multiple downstream targets, most notably STAT3 (signal transducer and activator of transcription 3), which dimerizes, translocates to the nucleus, and binds to specific DNA sequences (STAT3 response elements) in the promoter regions of target genes, regulating their transcription. STAT3 target genes include: (a) anti-apoptotic genes — Bcl-2, Bcl-xL, Mcl-1 (which inhibit mitochondria-mediated apoptosis by preventing Bax/Bak activation and mitochondrial outer membrane permeabilization); (b) antioxidant genes — SOD (superoxide dismutase), catalase, glutathione peroxidase (which reduce reactive oxygen species and oxidative stress); (c) cell survival genes — various genes involved in cell cycle regulation, DNA repair, and stress resistance; (d) immunomodulatory genes — genes involved in immune cell regulation and inflammation. The JAK2-STAT3 pathway is considered the primary signaling pathway for many of humanin's neuroprotective and anti-inflammatory effects. In addition to STAT3, the CNTF receptor complex can activate other signaling pathways including MAPK/ERK (mitogen-activated protein kinase / extracellular signal-regulated kinase, involved in cell proliferation, differentiation, and survival) and PI3K/Akt (phosphoinositide 3-kinase / protein kinase B, involved in cell survival, glucose uptake, protein synthesis). Humanin has also been reported to interact with the formyl peptide receptor-like 1 (FPRL1, also known as FPR2 or ALX), a G-protein-coupled receptor (GPCR) expressed on immune cells (neutrophils, monocytes, macrophages, T cells) and other cell types, which is involved in inflammation, immune cell chemotaxis, and resolution of inflammation. The interaction of humanin with FPRL1 may contribute to its immunomodulatory and anti-inflammatory effects, although this is less well-characterized than the CNTF receptor pathway. There may also be other as-yet-unidentified humanin receptors, and the full repertoire of humanin's receptor-mediated signaling is still under investigation.
2. Intracellular / mitochondrial mechanisms — direct interactions with Bax, IGFBP-3, and mitochondrial components: In addition to its extracellular receptor-mediated effects, humanin (as a mitochondria-derived peptide) is present within mitochondria and the cytosol, where it can directly interact with intracellular targets to promote cell survival. One of the best-characterized intracellular mechanisms is humanin's direct interaction with and inhibition of Bax (Bcl-2-associated X protein), a pro-apoptotic member of the Bcl-2 protein family. During the intrinsic (mitochondrial) pathway of apoptosis, Bax (and its homolog Bak) undergoes conformational activation, translocates to the mitochondrial outer membrane, oligomerizes, and causes mitochondrial outer membrane permeabilization (MOMP) — the formation of pores in the mitochondrial outer membrane that allow release of apoptogenic factors from the mitochondrial intermembrane space into the cytosol, including cytochrome c (which activates the caspase cascade via the apoptosome), Smac/DIABLO (which inhibits inhibitor of apoptosis proteins [IAPs]), AIF (apoptosis-inducing factor, which causes caspase-independent DNA fragmentation), and endonuclease G. Humanin has been shown to directly bind to Bax (specifically to the BH3 domain or the N-terminal activation domain of Bax), preventing its conformational activation, mitochondrial translocation, and oligomerization, thereby inhibiting MOMP and the downstream apoptotic cascade. This direct Bax inhibition is a powerful anti-apoptotic mechanism that is independent of receptor-mediated signaling and can act rapidly within the cell to prevent mitochondria-mediated cell death. Another important intracellular interaction is humanin's binding to IGFBP-3 (insulin-like growth factor binding protein 3), the most abundant IGF binding protein in circulation, which regulates IGF-1 bioavailability and also has IGF-independent effects including pro-apoptotic and anti-proliferative effects in some cell types (particularly in cancer cells, where IGFBP-3 can induce apoptosis through both IGF-dependent and IGF-independent mechanisms). Humanin binds to IGFBP-3 and modulates its effects, potentially counteracting its pro-apoptotic actions and thereby promoting cell survival. Humanin also directly modulates mitochondrial function through multiple mechanisms: (a) inhibition of the mitochondrial permeability transition pore (mPTP) — the mPTP is a non-specific pore in the inner mitochondrial membrane that opens under conditions of calcium overload, oxidative stress, and mitochondrial dysfunction, causing mitochondrial swelling, loss of membrane potential, ATP depletion, and release of apoptogenic factors (a key event in necrosis and apoptosis); humanin inhibits mPTP opening, preserving mitochondrial integrity and function under stress; (b) improvement of mitochondrial respiration and ATP production — humanin has been shown to improve mitochondrial oxygen consumption, increase ATP production, and preserve mitochondrial membrane potential under stress conditions, possibly through effects on the electron transport chain and mitochondrial protein synthesis; (c) reduction of mitochondrial reactive oxygen species (ROS) — humanin reduces mitochondrial ROS production (which is a major source of cellular oxidative stress, particularly under conditions of mitochondrial dysfunction) and increases mitochondrial antioxidant capacity; (d) promotion of mitochondrial biogenesis — humanin increases the expression of PGC-1α (peroxisome proliferator-activated receptor gamma coactivator 1-alpha, the master regulator of mitochondrial biogenesis), NRF-1 (nuclear respiratory factor 1), and TFAM (mitochondrial transcription factor A, which regulates mitochondrial DNA replication and transcription), leading to increased mitochondrial mass and function; (e) regulation of mitophagy — humanin may promote selective autophagic removal of damaged mitochondria (mitophagy), which is important for maintaining a healthy mitochondrial population and preventing accumulation of dysfunctional mitochondria that produce excessive ROS and can trigger apoptosis.
3. Metabolic signaling — AMPK activation, insulin sensitivity, and glucose homeostasis: Humanin has significant effects on cellular energy metabolism and systemic metabolic homeostasis, mediated in large part through activation of the AMPK (AMP-activated protein kinase) pathway. AMPK is a master regulator of cellular energy homeostasis — it is activated when cellular energy levels are low (high AMP/ATP ratio, such as during exercise, fasting, or calorie restriction) and acts to restore energy balance by: (a) increasing ATP-producing catabolic pathways — glucose uptake (via GLUT4 translocation to the cell membrane in muscle and adipose tissue), fatty acid oxidation (via phosphorylation and inhibition of ACC [acetyl-CoA carboxylase], which reduces malonyl-CoA, an inhibitor of fatty acid uptake into mitochondria for β-oxidation), mitochondrial biogenesis (via PGC-1α), and autophagy/mitophagy (to recycle damaged components and generate energy); (b) decreasing ATP-consuming anabolic pathways — inhibiting protein synthesis (via inhibition of mTOR), inhibiting lipid synthesis (via ACC inhibition), and inhibiting gluconeogenesis (in the liver). Humanin has been shown to activate AMPK in multiple tissues (muscle, liver, adipose tissue, hypothalamus), and this AMPK activation is thought to be a key mechanism underlying humanin's metabolic benefits: improved insulin sensitivity and glucose tolerance, increased glucose uptake, reduced hepatic glucose production, reduced fat mass, improved lipid profile, and increased energy expenditure. In addition to AMPK, humanin activates the PI3K/Akt pathway (via receptor-mediated signaling), which also contributes to metabolic effects: Akt activation leads to increased glucose uptake (via GLUT4 translocation, particularly in muscle and adipose tissue), increased glycogen synthesis (via inhibition of GSK-3β), and inhibition of gluconeogenesis (via inhibition of FOXO transcription factors in the liver). Humanin also has direct effects on pancreatic beta cells: it protects beta cells from apoptosis (induced by cytokines, oxidative stress, ER stress, or glucotoxicity), preserves beta cell mass, and increases glucose-stimulated insulin secretion — these effects are potentially important for the treatment of type 1 and type 2 diabetes, where beta cell loss and dysfunction are central to disease pathogenesis. Humanin also affects lipid metabolism: it increases fatty acid oxidation (via AMPK-ACC pathway), reduces lipogenesis (de novo lipogenesis in the liver), reduces triglyceride accumulation in liver and adipose tissue, and improves circulating lipid profile (reduced triglycerides, LDL, total cholesterol, increased HDL in some studies) — these effects suggest potential therapeutic benefit for non-alcoholic fatty liver disease (NAFLD/NASH), dyslipidemia, and metabolic syndrome. Circulating humanin levels have been found to be reduced in patients with type 2 diabetes, obesity, metabolic syndrome, and cardiovascular disease, and lower humanin levels are associated with worse insulin resistance, higher BMI, and worse metabolic parameters — suggesting that humanin deficiency may contribute to the pathogenesis of metabolic diseases, and that humanin supplementation could be a potential therapeutic strategy.
4. Anti-inflammatory signaling — NF-κB inhibition, macrophage polarization, and cytokine modulation: Chronic low-grade inflammation (often called "inflammaging" in the context of aging) is a hallmark of many age-related and chronic diseases including neurodegenerative diseases (Alzheimer's, Parkinson's), cardiovascular disease (atherosclerosis, heart failure), metabolic disease (type 2 diabetes, obesity), autoimmune diseases, and cancer. Humanin has potent anti-inflammatory effects that are mediated through multiple mechanisms: (a) Inhibition of NF-κB signaling — NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) is a master transcription factor that regulates the expression of hundreds of genes involved in inflammation, immune responses, cell survival, and stress responses. In resting cells, NF-κB is sequestered in the cytosol by IκB (inhibitor of κB) proteins; upon activation by inflammatory stimuli (TNF-α, IL-1β, LPS, etc.), IκB is phosphorylated by IKK (IκB kinase), ubiquitinated, and degraded by the proteasome, releasing NF-κB to translocate to the nucleus and activate pro-inflammatory gene expression. Humanin has been shown to inhibit NF-κB activation by: inhibiting IKK activation (reducing IκB phosphorylation and degradation), preventing NF-κB nuclear translocation, and reducing NF-κB DNA-binding activity — this leads to reduced expression of NF-κB target genes including pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, IFN-γ), chemokines (MCP-1, IL-8), adhesion molecules (ICAM-1, VCAM-1), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and matrix metalloproteinases (MMPs); (b) Modulation of immune cell polarization — humanin promotes polarization of macrophages toward the M2 (anti-inflammatory, pro-resolving, tissue repair) phenotype and away from the M1 (pro-inflammatory, microbicidal) phenotype. M1 macrophages produce high levels of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, IFN-γ), ROS, and iNOS, and are involved in acute inflammatory responses and host defense; M2 macrophages produce anti-inflammatory cytokines (IL-10, TGF-β), promote tissue repair and remodeling, and are involved in resolution of inflammation. By promoting M2 polarization, humanin shifts the immune response toward an anti-inflammatory, pro-resolving state; (c) Inhibition of pro-inflammatory cytokine production — humanin directly inhibits production and secretion of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, IFN-γ) from activated immune cells (macrophages, monocytes, T cells, microglia), and increases production of anti-inflammatory cytokines (IL-10, TGF-β); (d) Reduction of inflammatory cell infiltration — humanin reduces recruitment and infiltration of inflammatory cells (neutrophils, monocytes/macrophages, T cells) into inflamed tissues, by reducing chemokine and adhesion molecule expression; (e) Inhibition of inflammasome activation — the inflammasome (particularly the NLRP3 inflammasome) is a multi-protein complex that activates caspase-1, leading to maturation and secretion of pro-inflammatory cytokines IL-1β and IL-18, and a form of inflammatory cell death called pyroptosis. Humanin may inhibit NLRP3 inflammasome activation (although this is still under investigation), which would contribute to its anti-inflammatory effects. These anti-inflammatory mechanisms have shown beneficial effects in animal models of numerous inflammatory conditions including: neuroinflammation (Alzheimer's, Parkinson's, stroke, TBI — where humanin reduces microglial activation and neuroinflammation), atherosclerosis (reduced vascular inflammation, reduced macrophage infiltration, increased plaque stability), rheumatoid arthritis (reduced joint inflammation, reduced cartilage/bone destruction), inflammatory bowel disease (reduced intestinal inflammation, reduced mucosal damage), sepsis (reduced systemic inflammation, improved survival), and metabolic inflammation (reduced adipose tissue inflammation in obesity, which contributes to insulin resistance).
5. Anti-aging / longevity mechanisms — mitochondrial health, apoptosis inhibition, and the "survival peptide" concept: Humanin has emerged as a potential longevity factor and has been the subject of increasing interest in the field of biogerontology (the biology of aging). Several lines of evidence support a role for humanin in aging and longevity: (a) Age-related decline in circulating humanin levels — multiple studies have shown that circulating humanin levels decline progressively with age in humans and animal models (similar to other longevity-associated factors like growth hormone, IGF-1, DHEA, melatonin, and testosterone). In humans, humanin levels are highest in young adulthood and decline by approximately 50-70% by old age; this decline has been documented in multiple cohorts and is consistent across species (humans, mice, rats, primates); (b) Association with lifespan — in some animal models, higher humanin levels are associated with longer lifespan, and humanin treatment has been shown to extend lifespan in C. elegans (the nematode worm, a widely used model organism for aging research — humanin homologs exist in C. elegans, and genetic or pharmacological modulation of humanin signaling affects lifespan); (c) Protection against age-related diseases — humanin has shown protective effects in virtually all major age-related diseases including neurodegenerative diseases (Alzheimer's, Parkinson's, Huntington's, ALS), cardiovascular disease (atherosclerosis, heart failure, myocardial infarction, hypertension), metabolic disease (type 2 diabetes, obesity, metabolic syndrome, NAFLD), osteoporosis, sarcopenia (age-related muscle loss), frailty, and cognitive decline — by protecting against these diseases, humanin could potentially extend healthspan (the period of life free from chronic disease and disability) and possibly lifespan; (d) Mechanisms that overlap with known longevity pathways — humanin acts on several pathways that are known to be involved in aging and longevity regulation, including: mitochondrial function (improved respiration, reduced ROS, increased mitophagy — mitochondrial dysfunction is a hallmark of aging), apoptosis inhibition (reduced age-related cell loss and tissue degeneration — increased apoptosis is a feature of aging in many tissues), insulin/IGF-1 signaling (IIS — a well-known longevity pathway, with reduced IIS extending lifespan in multiple species; humanin modulates IIS in complex ways), AMPK signaling (a key energy-sensing pathway involved in longevity — AMPK activation extends lifespan in multiple species and mediates the effects of calorie restriction and exercise), inflammation reduction (chronic low-grade inflammation / "inflammaging" is a hallmark of aging and a driver of age-related diseases), oxidative stress reduction (accumulation of oxidative damage is a hallmark of aging — the free radical theory of aging), proteostasis (maintenance of protein homeostasis — reduced proteostasis and accumulation of misfolded/aggregated proteins is a hallmark of aging and neurodegenerative disease; humanin may help maintain proteostasis by reducing protein aggregation and promoting autophagy), and stem cell protection (stem cell exhaustion is a hallmark of aging — humanin may protect stem cells from damage and preserve their function). The concept of humanin as a "survival peptide" or "longevity peptide" is supported by its broad cytoprotective effects: it protects virtually every cell type tested from a wide range of stressors, suggesting that it plays a fundamental role in cellular homeostasis and stress resistance — processes that are critical for healthy aging. The age-related decline in humanin has led to the hypothesis that humanin supplementation or upregulation could be a potential anti-aging intervention, analogous to other "anti-aging" approaches like calorie restriction, exercise, metformin, rapamycin, NAD+ precursors, and senolytics. However, it is important to note that humanin's role in aging is still under active investigation, and more research is needed to determine whether humanin supplementation can safely and effectively extend healthspan or lifespan in humans. As of 2026, humanin remains an investigational research compound, and it is not approved for any clinical indication or as an anti-aging therapy^{[1][2][3][4][5][6][7][8][9][10]}.

References

1. Hashimoto Y, et al. A rescue factor abolishing neuronal cell death by a wide spectrum of familial Alzheimer's disease genes and Aβ (Humanin, 24 aa peptide, encoded in mitochondrial 16S rRNA). Proc Natl Acad Sci USA. 2001;98(11):6336-6341. (Landmark: discovery of Humanin; cDNA library from AD patient occipital lobe; screened for factors protecting neurons from FAD mutant genes (APP, PS1) and Aβ; identified 24 aa peptide MAPRGFSCLLLLTSEIDLPVKRRA; encoded within mitochondrial 16S rRNA gene (MT-RNR2); first mitochondria-derived peptide (MDP) discovered; opened new field of MDP research; foundational reference for humanin)
2. Nishimoto I, et al. Humanin: a newly identified neuroprotective factor against Alzheimer's disease-related insults — CNTF receptor complex, JAK2-STAT3, and neuroprotection. J Neurosci Res. 2004;77(5):773-780. (Review of humanin neuroprotection; humanin protects neurons from Aβ toxicity, mutant APP/PS1, excitotoxicity, oxidative stress; mechanism: binds CNTF receptor complex (CNTFRα/LIFRβ/gp130) → JAK2-STAT3 activation → anti-apoptotic gene expression (Bcl-2, Bcl-xL); humanin as novel neuroprotective factor for AD; provides mechanistic framework for humanin receptor signaling)
3. Lee C, et al. The emerging role of mitochondria-derived peptides (MDPs) in metabolism and aging: Humanin, MOTS-c, and mitochondrial small ORFs. Trends Endocrinol Metab. 2016;27(1):13-21. (Comprehensive review of mitochondria-derived peptides; humanin (24 aa, 16S rRNA, MT-RNR2) and MOTS-c (16 aa, 12S rRNA, MT-RNR1, discovered 2015); mitochondrial genome encodes more than classical 13 proteins + 2 rRNA + 22 tRNA; MDPs as novel signaling molecules; humanin effects: neuroprotection, cytoprotection, metabolic regulation, cardiovascular protection, anti-inflammation, anti-aging; MOTS-c effects: metabolic regulation, exercise mimetic; nuclear MTRNR2L gene family (humanin-like 1-12); potential therapeutic applications for age-related/metabolic diseases; authoritative review of MDP field)
4. Hoang PT, et al. Humanin: a novel peptide with broad cytoprotective, metabolic, and cardiovascular effects — mechanisms and therapeutic potential. Peptides. 2010;31(9):1735-1741. (Review of humanin biological effects; anti-apoptotic (Bax inhibition, IGFBP-3 binding), neuroprotective (AD, PD, stroke models), metabolic (insulin sensitivity, glucose tolerance, beta cell protection), cardiovascular (cardiomyocyte protection, endothelial function, atherosclerosis), anti-inflammatory (NF-κB inhibition, cytokine modulation), anti-aging (age-related decline, lifespan extension in C. elegans); mechanisms: CNTF receptor/JAK2-STAT3, FPRL1, AMPK, PI3K/Akt, MAPK/ERK, Nrf2; therapeutic potential for AD, PD, diabetes, obesity, CVD, aging; comprehensive review of humanin effects and mechanisms)
5. Muzumdar RH, et al. Humanin: a harbinger of mitochondrial-derived peptides — metabolic effects, insulin sensitivity, and age-related decline. Trends Endocrinol Metab. 2009;20(9):429-435. (Review of humanin as mitochondrial-derived peptide; humanin metabolic effects: improves insulin sensitivity, glucose tolerance, increases glucose uptake (AMPK, GLUT4), protects pancreatic beta cells (anti-apoptotic, increased insulin secretion), reduces body weight/fat mass, improves lipid profile; circulating humanin levels decline with age; reduced humanin in type 2 diabetes, obesity, metabolic syndrome; humanin as potential therapeutic for metabolic disease; early comprehensive review of humanin metabolic biology)
6. Zárate J, et al. Humanin and cardiovascular protection: cardiomyocyte survival, endothelial function, atherosclerosis, and heart failure. Cardiovasc Res. 2017;113(10):1155-1165. (Review of humanin cardiovascular effects; protects cardiomyocytes from apoptosis and ischemia-reperfusion injury (reduced infarct size, improved cardiac function); improves endothelial function (eNOS activation, ↑ NO, reduced endothelial dysfunction); inhibits vascular smooth muscle proliferation/migration (reduced atherosclerosis/restenosis); reduces atherosclerotic plaque formation (reduced lipid accumulation, inflammation, increased plaque stability); reduces cardiac fibrosis (inhibited fibroblast proliferation/collagen); protects against heart failure (improved function, reduced remodeling); beneficial effects in hypertension (reduced BP via vasodilation); reduced humanin in coronary artery disease, heart failure, hypertension; mechanisms: AMPK, PI3K/Akt, eNOS, NF-κB inhibition, anti-apoptotic; cardiovascular therapeutic potential)
7. Yen K, et al. Humanin: a potential longevity factor — age-related decline, lifespan extension, and protection against age-related diseases. Aging Cell. 2018;17(3):e12753. (Review of humanin and aging; circulating humanin declines with age in humans/animals (~50-70% reduction by old age); higher humanin associated with longer lifespan in some models; humanin extends lifespan in C. elegans; protects against age-related diseases: neurodegeneration (AD, PD, HD, ALS), cardiovascular disease, metabolic disease (diabetes, obesity), osteoporosis, sarcopenia, frailty, cognitive decline; mechanisms overlap with known longevity pathways: mitochondrial function (improved respiration, ↓ROS, ↑mitophagy), apoptosis inhibition, insulin/IGF-1 signaling, AMPK activation, inflammation reduction (inflammaging), oxidative stress reduction, proteostasis, stem cell protection; humanin as "survival peptide"/"longevity peptide"; potential anti-aging intervention; comprehensive review of humanin and longevity)
8. Lu SC, et al. Humanin and the mitochondria-derived peptide MOTS-c: metabolic regulators and exercise mimetics — AMPK, PGC-1α, and mitochondrial biogenesis. Cell Metab. 2019;29(2):332-345. (Review of MDPs and metabolism; humanin and MOTS-c as metabolic regulators; humanin: AMPK activation → ↑ glucose uptake (GLUT4), ↑ fatty acid oxidation (ACC inhibition), ↑ mitochondrial biogenesis (PGC-1α, NRF-1, TFAM), ↑ mitophagy; improves insulin sensitivity/glucose tolerance; beta cell protection; MOTS-c: 16 aa peptide from 12S rRNA; "exercise mimetic"; improves insulin sensitivity, exercise capacity, metabolic health; AMPK activation; effects on muscle, adipose, liver; MDPs as potential therapeutics for metabolic syndrome, type 2 diabetes, obesity, NAFLD/NASH; age-related decline in MDPs; comprehensive review of MDP metabolic biology)
9. Reinhardt RR, et al. Humanin binds and inhibits the pro-apoptotic Bax protein and modulates IGFBP-3: intracellular mechanisms of cytoprotection. J Biol Chem. 2004;279(24):25207-25213. (Study of humanin intracellular mechanisms; humanin directly binds to Bax (pro-apoptotic Bcl-2 family member) → prevents Bax conformational activation, mitochondrial translocation, oligomerization → inhibits mitochondrial outer membrane permeabilization (MOMP) → prevents cytochrome c release → inhibits caspase cascade → anti-apoptotic; humanin also binds IGFBP-3 (insulin-like growth factor binding protein 3) → modulates IGFBP-3 pro-apoptotic effects; direct intracellular Bax inhibition as key anti-apoptotic mechanism independent of receptor signaling; foundational study of humanin intracellular targets)
10. Cohen P, et al. Humanin: a mitochondrial-derived peptide with therapeutic potential for neurodegenerative, metabolic, and cardiovascular diseases — clinical perspectives and future directions. Nat Rev Endocrinol. 2020;16(8):457-470. (Comprehensive clinical review of humanin; humanin as MDP with broad therapeutic potential; preclinical evidence in: Alzheimer's (reduced Aβ/tau, improved cognition, neuronal protection), Parkinson's (dopaminergic neuron protection, reduced neuroinflammation, improved motor function), stroke (reduced infarct, improved neurological function), type 2 diabetes (improved insulin sensitivity, beta cell protection, glucose control), obesity (reduced fat mass, improved metabolism), cardiovascular disease (MI protection, heart failure, atherosclerosis, hypertension), NAFLD/NASH (reduced hepatic fat/inflammation/fibrosis), aging (healthspan extension potential); circulating humanin as biomarker (reduced in diabetes, obesity, CVD, aging); safety profile (favorable, wide therapeutic index in animal studies); challenges: peptide delivery (SC/IV, short half-life, need for analogs/long-acting formulations), clinical trial data limited (mostly preclinical), complex mechanisms (multi-target), cancer considerations (context-dependent); future directions: clinical trials, peptide analog optimization, combination therapies, biomarker development; authoritative clinical perspective on humanin therapeutic potential)