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MDP · Humanin-G) — where serine at position 14 is replaced by glycine — is 1 · 000 to 10 · 000 times more potent than native Humanin · is used in most animal research
Humanin is the mitochondrial peptide that told us mitochondria are endocrine organs. Its discovery was more revolutionary than its community discourse reflects. The longevity correlations are among the most compelling in aging biology. And the IGF-1 inverse relationship is the most consequential underappreciated fact in the longevity peptide space.
The central tension resolved: Humanin levels decline with age in every species studied. People whose parents and grandparents lived to 100+ have more of it than their peers. The longest-lived mammal (naked mole-rat) maintains it throughout its exceptional lifespan. People with genetic mutations that suppress IGF-1 — who have low cancer rates and extended healthspan — have 80% more of it. And the compound that produced the highest circulating levels in a human intervention wasn't longevity-focused at all: it was GH treatment, which drops Humanin by ~20%. The standard community GH secretagogue protocol likely suppresses endogenous Humanin. Whether this matters, and whether exogenous HNG compensates for it, is the most important unanswered protocol question in the mitochondrial longevity stack.
The strongest argument for Humanin: the evidence architecture is more distributed than most longevity compounds. Neuroprotection against Aβ has been confirmed in multiple independent labs across multiple countries. The cardiovascular correlation is from the Mayo Clinic, not Cohen's group. The metabolic data is from Barzilai's group at Einstein. The longevity correlation is from Cohen's group but uses multiple independent species and human cohort designs that are methodologically credible. The C. elegans lifespan extension is well-documented and autophagy-dependent — one of the most conserved longevity pathways in biology. Humanin is not a Khavinson-type single-source compound.
The strongest argument for caution: no human intervention trial exists. The centenarian correlation is compelling but observational. The IGF-1 inverse relationship makes the pharmacological context of supplementing HNG in a high-IGF-1 environment (GH secretagogue users) different from the low-IGF-1 environment where high Humanin is associated with longevity. And the IGFBP-3 neutralization mechanism creates a theoretical cancer concern that is different in character depending on the IGF-1 context.
In 2001, a team led by Ikuo Nishimoto at Keio University in Tokyo was doing something straightforward: screening a library of genes expressed in the brains of Alzheimer's patients for any sequence that could protect neurons from Alzheimer's disease-relevant cell death. The approach was essentially a biological rescue experiment — transfect cells that were dying from AD-related insults with random gene sequences from a patient's brain, and see which ones kept the cells alive.
The tissue they chose for the cDNA library was specific: the occipital cortex of a patient with familial Alzheimer's disease. The occipital cortex is the visual processing region at the back of the brain. In this particular patient — and in Alzheimer's disease generally — the occipital cortex is one of the last regions to be destroyed. The rest of the brain had been consumed by the disease. The occipital cortex survived. They were, in effect, asking the surviving neurons what they knew that the dead neurons did not.
The sequence they found was 24 amino acids long. It was not a known protein. When they looked it up in genomic databases, they found it corresponded not to any nuclear-encoded gene but to a sequence within the 16S ribosomal RNA gene of the mitochondrial genome — the circular, compact DNA molecule inside mitochondria that is inherited exclusively from the mother and has been continuously optimized over billions of years of evolution. They named the peptide 'Humanin' — a name that captures something of the poetry of its discovery: the thing that remained human while the rest was being taken away.
The discovery was more revolutionary than it initially appeared. At the time, the mitochondrial genome was thought to encode a fixed set of molecules: 13 proteins that are subunits of the electron transport chain, 22 transfer RNAs, and 2 ribosomal RNAs. Period. Nothing else. Humanin did not fit this inventory. It was a small open reading frame within the 16S rRNA gene — a peptide-coding sequence hidden inside what was thought to be purely structural RNA. Its discovery suggested that the mitochondrial genome had more to say about the cell's biology than anyone had appreciated.
The subsequent decade and a half revealed how much more. Pinchas Cohen, initially at UCLA and later at USC's Davis School of Gerontology, built a research program around Humanin and the broader concept of mitochondrial-derived peptides (MDPs). His group discovered MOTS-c (also encoded in mitochondrial DNA, also a signaling peptide, also covered in this book) and catalogued six additional small humanin-like peptides (SHLP1-6) encoded in the same 16S rRNA region. Each discovery reinforced the same paradigm-shifting conclusion: mitochondria are endocrine organelles. They produce signaling peptides that communicate metabolic status, stress levels, and cellular health to the rest of the organism. Humanin was the first known word in a language the cell had been speaking for billions of years that scientists had only just learned to read.
THE CENTRAL TENSION — THE COMMUNITY'S MOST IMPORTANT BLIND SPOT
Humanin levels decline with age. Children of centenarians have higher Humanin levels than age-matched controls. Animals with mutations that extend lifespan have elevated Humanin. These correlations are among the most compelling longevity biomarker findings in the aging literature. The community has responded by supplementing with Humanin/HNG. What the community has generally not processed: Humanin and IGF-1 are inversely regulated. GH treatment drops plasma Humanin by ~20% in humans. Laron Syndrome patients — who have GH receptor deficiency, extremely low IGF-1, and virtually no cancer — have 80% HIGHER Humanin than matched controls. The community routinely uses GH secretagogues (CJC-1295, Ipamorelin) to raise GH and IGF-1 for anti-aging purposes. Those same interventions likely suppress Humanin. If Humanin is a genuine longevity signal and not merely a correlate, the most popular anti-aging peptide protocol in the community may be working against the very mitochondrial signal that predicts longevity. This tension has not been resolved. It needs to be understood before any protocol decision is made.
Humanin's evidence is more diverse across organ systems than MOTS-c or SS-31, reflecting its multiple receptor mechanisms. The neuroprotection literature is the deepest. The longevity associations are the most compelling. The metabolic data is real but secondary.
The foundational finding: Humanin protects neurons from Alzheimer's disease-relevant cell death. Multiple independent labs have confirmed this in cell culture — Humanin and HNG protect against Aβ1-42 toxicity, FAD gene-induced apoptosis, oxidative stress, and excitotoxicity in neuronal cells. The protection is robust, reproducible, and mechanistically characterized through both FPR2 receptor competition with Aβ and intracellular Bax/IGFBP-3 neutralization. Grade A for in vitro neuroprotection against Aβ (multiple independent labs; extensively replicated). In animal models: HNG protects against cognitive decline in aging mice (Scientific Reports 2018), reduces Aβ burden in AD mouse models, and prevents hippocampal neuronal loss after ischemia. Grade B for animal model neuroprotection (multiple labs; Cohen group primary; independent Japanese and US replication exists).
Important limitation: the gap between in vitro and clinical Alzheimer's treatment has been traversed by many promising compounds that ultimately failed in human trials. Humanin's neuroprotective potency in cell culture and animal models does not predict Phase 3 success — as decades of Alzheimer's drug development history demonstrates. No Humanin or HNG human trial for Alzheimer's has been registered or completed.
Middle-aged mice treated with HNG twice weekly for 6-10 months showed significant cognitive benefits: improved rotarod performance, better search strategy in Barnes maze, improved Y-maze spontaneous alternation — standardized measures of hippocampal-dependent memory and spatial navigation. These improvements were measured in middle-aged mice treated prophylactically, not just as rescue therapy after established neurodegeneration. The human correlative data: a study by Cohen's group found that plasma Humanin levels were associated with improved 'cognitive age' in human subjects — those with higher Humanin levels performed cognitively as if they were younger than their chronological age. Grade B for animal cognitive prevention data (Scientific Reports 2018; Cohen group); Grade B-C for human correlative cognitive finding (observational; no intervention).
The longevity data for Humanin is the most striking of any biomarker finding in this book — and it is purely observational. Key data points from Cohen et al. (Aging, 2020): (1) Humanin levels decline progressively with age in mice, rats, and humans — from approximately 200-300 ng/mL in young adults to 80-100 ng/mL by the sixth or seventh decade; (2) Naked mole-rats, the mammalian model of negligible senescence (they live 30+ years, develop no obesity, are highly cancer-resistant, and barely age physiologically), maintain stable Humanin levels throughout their exceptional lifespan; (3) Children of centenarians have significantly higher Humanin levels than age-matched controls without long-lived parents; (4) Humanin levels are decreased in Alzheimer's disease patients and in patients with MELAS (a mitochondrial disease with accelerated neurodegeneration). In C. elegans, Humanin overexpression extends lifespan via daf-16/FOXO — one of the most conserved longevity pathways in biology. Grade B: compelling observational human data; lifespan extension in C. elegans well-documented; aging mouse data (transgenic and pharmacological HNG) shows healthspan benefits.
Circulating Humanin levels are associated with preserved coronary endothelial function in human observational data (Widmer et al., American Journal of Physiology, 2013) — one of the few independent cardiovascular Humanin findings outside Cohen's group. Endothelial dysfunction is a major driver of cardiovascular disease, and the correlation between higher Humanin and better endothelial function is mechanistically coherent with Humanin's anti-apoptotic, anti-inflammatory signaling. Animal studies: Humanin reduces infarct size in cardiac ischemia-reperfusion models, protects cardiomyocytes from apoptosis after ischemic injury, and reduces atherosclerotic plaque burden in apoE knockout mice. Grade B-C: independent human correlative data + replicable animal cardiovascular protection.
Muzumdar et al. (PLoS ONE, 2009) characterized Humanin as a central regulator of peripheral insulin action: HN improved insulin sensitivity in skeletal muscle in animal models; circulating HN levels were decreased with age in both rodents and humans (measured in hypothalamus, skeletal muscle, and cortex); a single injection of potent HN analog significantly lowered blood glucose in Zucker diabetic fatty rats. The mechanism: Humanin's GP130/WSX-1/CNTFR receptor complex activates STAT3, which enhances insulin signaling in peripheral tissues. This metabolic effect is mechanistically distinct from MOTS-c's AMPK-mediated metabolic effects — different receptor, different signaling cascade, potentially complementary. Grade B: multiple independent publications; metabolic effects replicated across models.
Humanin's relationship to cancer is nuanced and has two apparently contradictory dimensions. First: Humanin inhibits IGFBP-3 — and IGFBP-3 promotes apoptosis in cancer cells as well as healthy cells. Blocking IGFBP-3-induced apoptosis could theoretically protect cancer cells from cell death. This is a theoretical concern that applies to Humanin's cytoprotective mechanism broadly. Second: Laron Syndrome patients (with very high Humanin) have virtually no cancer. The cancer-resistant phenotype of the Humanin-high / IGF-1-low state argues against the worry that high Humanin promotes cancer. The probable resolution: the IGF-1-low environment that produces high Humanin is comprehensively anti-cancer through multiple mechanisms that dominate over any theoretical pro-survival effect of Humanin's IGFBP-3 neutralization. However, in a high-IGF-1 environment (normal or GH-supplemented), Humanin's IGFBP-3 neutralization without the broader IGF-1-suppressive context creates a different risk calculation. No direct human cancer data for Humanin supplementation exists. Grade C: complex theoretical landscape; active malignancy caution applies.
Humanin: 24 amino acids. Full sequence: Met-Ala-Pro-Arg-Gly-Phe-Ser-Cys-Leu-Leu-Leu-Leu-Thr-Ser-Glu-Ile-Asp-Leu-Pro-Val-Lys-Arg-Arg-Ala. Molecular formula: C119H204N34O32S2. Molecular weight approximately 2,689 Da. The N-terminal methionine and three subsequent amino acids form a signal sequence — the 21-amino acid mature secreted form (positions 4-24) is often cited in older literature, leading to some discrepancy between sources citing a '21-amino acid' vs '24-amino acid' peptide. The full 24-amino acid form is the sequence encoded in the mitochondrial genome and produced synthetically for research. The gene is located within MT-RNR2 (mitochondrial 16S rRNA) on the heavy strand.
The peptide is highly conserved across vertebrate species — suggesting evolutionary pressure to maintain its function, which is one of the signals that it is biologically meaningful rather than an artifact. It is also found in organisms as phylogenetically distant as C. elegans, suggesting the mitochondrial longevity signaling function is ancient.
HNG vs NATIVE HUMANIN — THIS DISTINCTION MATTERS FOR EVERYTHING
Native Humanin (HN) is the 24-amino acid sequence directly encoded in mitochondrial DNA. HNG (S14G-Humanin, Humanin-G) is a synthetic analog where the serine at position 14 is replaced by glycine. This single amino acid substitution makes HNG 1,000 to 10,000 times more potent than native Humanin across multiple assay systems. Why? The position 14 serine is a phosphorylation site — modification at this position in native Humanin reduces its activity. Replacing it with glycine (which cannot be phosphorylated) locks HNG in a constitutively active conformation. Essentially all animal studies published after the early 2000s use HNG rather than native Humanin. Most community research peptide vendors sell HNG rather than native Humanin. When you read Humanin research, you are almost certainly reading HNG research. When you buy 'Humanin' from a research vendor, you are almost certainly getting HNG. This matters because HNG's pharmacology, receptor engagement, and effective doses are not identical to native Humanin's. The clinical relevance of supplementing with an analog that is orders of magnitude more potent than the endogenous molecule has not been studied.
Beyond HNG, several other Humanin analogs have been characterized in research settings. HNGF6A (S14G + F6A substitution) is even more potent in some models. AGA-HNG (an amphipathic helix-modified version) has enhanced CNS penetration properties. The community primarily uses HNG; HNGF6A appears in some advanced community protocols. For all practical purposes, when this chapter discusses Humanin effects, it is discussing HNG effects.
HNG: lyophilized powder reconstituted with bacteriostatic water. Solution is clear to slightly opalescent. Refrigerate at 2-8C after reconstitution; use within 30 days. The cysteine at position 7 (Cys7) can form disulfide bonds — relevant for oxidation in solution. Minimize air exposure during reconstitution; store in darkness. Mass spectrometry confirming the HNG molecular weight is the identity check (HNG MW: approximately 2,646 Da — slightly less than native Humanin due to the S→G substitution). HPLC purity 98%+.
Humanin's mechanisms are unusually diverse — it operates through both extracellular receptor signaling and intracellular protein-protein interactions, engaging cytoprotective pathways at multiple levels simultaneously. This breadth is part of what makes it compelling as a longevity signal.
On the cell surface, Humanin binds a tripartite receptor complex composed of CNTFR (ciliary neurotrophic factor receptor alpha), WSX-1 (IL-27 receptor alpha), and gp130 (IL6ST — the shared signaling subunit of the IL-6 receptor family). This complex is expressed in neurons, cardiomyocytes, liver cells, muscle, and multiple other tissues. When Humanin binds and activates this complex, it triggers downstream activation of JAK/STAT3, PI3K/Akt, and MAPK/ERK1/2 signaling pathways — all pro-survival cascades that promote cellular health and resistance to apoptosis. A secondary receptor, formyl peptide receptor 2 (FPR2/FPRL1), also binds Humanin and mediates anti-inflammatory effects, particularly in the context of beta-amyloid toxicity (FPR2 is the receptor through which beta-amyloid drives neuroinflammation; Humanin competes at this receptor). Grade B: receptor identification and downstream pathway activation confirmed by multiple independent labs; age-dependent signaling differences in hippocampus documented in vivo.
Intracellularly, Humanin physically binds and neutralizes pro-apoptotic proteins. The two best-characterized interactions: IGFBP-3 binding (IGF-binding protein 3 — which drives apoptosis independently of IGF-1 signaling; Humanin binding to IGFBP-3 blocks this apoptotic activity); and Bax binding (Bax is a key pro-apoptotic Bcl-2 family protein that triggers mitochondrial outer membrane permeabilization and cytochrome c release; Humanin binding to Bax inhibits this). Through both mechanisms, Humanin functions as a broad anti-apoptotic agent in cells under stress. Grade B: IGFBP-3 and Bax binding interactions confirmed by independent labs; mechanistically important for understanding both cytoprotection and the IGF-1 relationship.
One of the most recently characterized Humanin mechanisms is activation of chaperone-mediated autophagy (CMA) — a selective form of autophagy where specific proteins containing a KFERQ-like motif are recognized by HSC70 and trafficked to lysosomes for degradation. CMA is one of the central cellular quality control mechanisms through which caloric restriction, rapamycin, and fasting extend lifespan. Humanin is one of the few peptides to directly activate this same pathway. In C. elegans, Humanin's lifespan extension has been shown to be autophagy-dependent — blocking autophagy abolishes the lifespan benefit. Grade B-C: CMA activation confirmed in cell culture; autophagy-dependence of lifespan extension confirmed in C. elegans; mechanism in aging mammals not fully characterized.
Humanin and IGF-1 are not independent longevity signals — they are inversely regulated by a shared system. Cohen et al. demonstrated multiple lines of evidence for this: (1) Plasma Humanin levels are significantly negatively correlated with IGF-1 levels (Pearson's r = -0.69) in GH-deficient children; (2) GH treatment in these children — which raises IGF-1 — reduced Humanin levels by approximately 20%; (3) Laron Syndrome patients (GH receptor deficiency, extremely low IGF-1, famous for near-absence of cancer and extended healthspan) have 80% higher plasma Humanin than matched controls; (4) Animals with GH pathway mutations that extend lifespan (Ames dwarf, Snell dwarf, GH receptor knockout) all have elevated Humanin compared to wild-type.
The interpretation: Humanin is part of a mitochondrial signaling system that is upregulated when the GH/IGF-1 axis is suppressed. High IGF-1 = low Humanin. Low IGF-1 = high Humanin. The long-lived, cancer-resistant, Humanin-elevated Laron Syndrome population makes a compelling case that the Humanin-high / IGF-1-low state may be the biology that produces extended healthspan. The community pursuing GH secretagogues to raise IGF-1 may be creating the opposite hormonal environment. Grade B: human data (GH-deficient children + Laron Syndrome) with small n; multiple corroborating animal genetic models; mechanistic relationship not fully characterized.
THE IGF-1 QUESTION — WHAT IT MEANS FOR PROTOCOL DESIGN
The inverse relationship between Humanin and IGF-1 does not necessarily mean GH secretagogues are harmful — the biology is more complex than a simple see-saw. IGF-1 has beneficial effects on muscle mass, bone density, cognition, and tissue repair that make it genuinely valuable for many anti-aging applications. Laron Syndrome patients also have short stature and other challenges despite their cancer resistance and longevity. The question is not 'which is better' but 'what is the tradeoff, and is the community aware it is making it?' The answer is that most community users are not aware that CJC-1295/Ipamorelin protocols likely suppress Humanin, and the possibility that this suppression works against longevity goals has not been discussed or quantified. This chapter raises the question the community needs to hold — not a directive to stop using GH secretagogues.
Humanin's transcriptional effects flow from its receptor-mediated activation of STAT3, Akt, and ERK1/2 signaling cascades. STAT3 activation drives expression of pro-survival genes (Bcl-2, Bcl-xL, survivin), inflammatory resolution genes, and metabolic regulatory programs. PI3K/Akt activation promotes protein synthesis, nutrient sensing, and cellular stress tolerance gene expression. ERK1/2 activation drives proliferative and neuroprotective transcriptional programs. The age-dependent aspect documented by Cohen's group is particularly interesting: old mice (but not young mice) injected with Humanin showed increased AKT and ERK1/2 phosphorylation in the hippocampus — suggesting that Humanin's signaling effects may be specifically compensatory in aged tissue where endogenous Humanin has declined, rather than uniformly active at all ages. This finding implies that supplementing Humanin in younger individuals may have a different (and possibly smaller) effect than supplementing in older individuals where the pathway is more depleted.
The IGFBP-3 interaction has additional gene-level consequences: IGFBP-3 itself acts as a transcription factor and modulates nuclear gene expression related to apoptosis and cell cycle arrest. Humanin binding to IGFBP-3 not only blocks its direct apoptotic effects but may also influence the gene expression programs IGFBP-3 controls in the nucleus.
THE EVIDENCE ARCHITECTURE FOR HUMANIN
Humanin sits in a specific evidence position that distinguishes it from most compounds in this book. It has more human observational data than MOTS-c (aging decline documented in multiple human cohorts, centenarian offspring finding, cardiovascular correlation, cognitive age association) but no human intervention trial. Its animal evidence across multiple independent labs (neuroprotection, longevity in C. elegans, cognitive protection in aging mice) is among the better-replicated in this book. The limitation is the same for every application: we have strong human correlations and compelling animal data with no controlled human intervention. The transition from 'Humanin decline predicts aging-related decline' to 'restoring Humanin with exogenous HNG produces anti-aging benefit in humans' is the step that has not been taken in clinical trials.
Application
Evidence Type
Grade
Key Finding
Limitation
Aβ neuroprotection (in vitro)
Multiple independent cell culture studies
A
Humanin/HNG protects neurons from Aβ toxicity; FPR2 + Bax + IGFBP-3 mechanisms confirmed
Cell culture; not in vivo human neurons; Alzheimer's drug pipeline history cautionary
Neuroprotection in animal models
Multiple species, multiple labs
B
Reduces Aβ burden; protects from ischemia; prevents AD-related apoptosis in mice
Animal; no human AD trial
Cognitive aging prevention
Aging mouse study (Cohen/Sci Reports 2018)
B
HNG twice weekly prevented age-related cognitive decline across multiple behavioral tests
Single group; aging mice; no human RCT
Longevity correlation (human observational)
Cohen et al. Aging 2020
B
Centenarian offspring have higher Humanin; naked mole-rat levels stable; age-related decline confirmed
Observational; correlation not causation; Cohen group primary
C. elegans lifespan extension
Cohen group
B
Humanin overexpression extends lifespan via daf-16/FOXO; autophagy-dependent
Invertebrate; translation to mammals and humans uncertain
Cardiovascular correlation
Widmer et al. 2013 (independent)
B-C
Higher Humanin associated with preserved coronary endothelial function in humans
Observational; independent lab adds credibility; no intervention
Insulin sensitivity / metabolic
Muzumdar 2009 (independent)
B
Humanin regulates peripheral insulin action; plasma decline with age in humans confirmed
No intervention trial; animal primary
IGF-1 inverse regulation
Cohen group; Laron Syndrome data
B
GH treatment drops Humanin ~20%; Laron Syndrome (low IGF-1) = 80% higher Humanin
Small n; Cohen group; mechanism not fully characterized
Human anti-aging benefit
None
X
No intervention trial completed or registered
Not yet tested in controlled human trial
| Application | Evidence level | Grade | Confidence | Key limitation |
|---|---|---|---|---|
| Aβ neuroprotection (in vitro) | Multiple independent cell culture studies | A | Humanin/HNG protects neurons from Aβ toxicity; FPR2 + Bax + IGFBP-3 mechanisms confirmed | Cell culture; not in vivo human neurons; Alzheimer's drug pipeline history cautionary |
| Neuroprotection in animal models | Multiple species, multiple labs | B | Reduces Aβ burden; protects from ischemia; prevents AD-related apoptosis in mice | Animal; no human AD trial |
| Cognitive aging prevention | Aging mouse study (Cohen/Sci Reports 2018) | B | HNG twice weekly prevented age-related cognitive decline across multiple behavioral tests | Single group; aging mice; no human RCT |
| Longevity correlation (human observational) | Cohen et al. Aging 2020 | B | Centenarian offspring have higher Humanin; naked mole-rat levels stable; age-related decline confirmed | Observational; correlation not causation; Cohen group primary |
| C. elegans lifespan extension | Cohen group | B | Humanin overexpression extends lifespan via daf-16/FOXO; autophagy-dependent | Invertebrate; translation to mammals and humans uncertain |
| Cardiovascular correlation | Widmer et al. 2013 (independent) | B-C | Higher Humanin associated with preserved coronary endothelial function in humans | Observational; independent lab adds credibility; no intervention |
| Insulin sensitivity / metabolic | Muzumdar 2009 (independent) | B | Humanin regulates peripheral insulin action; plasma decline with age in humans confirmed | No intervention trial; animal primary |
| IGF-1 inverse regulation | Cohen group; Laron Syndrome data | B | GH treatment drops Humanin ~20%; Laron Syndrome (low IGF-1) = 80% higher Humanin | Small n; Cohen group; mechanism not fully characterized |
| Human anti-aging benefit | None | X | No intervention trial completed or registered | Not yet tested in controlled human trial |
NO VALIDATED HUMAN DOSE EXISTS
HNG has no published pharmacokinetic study in humans. No dose-finding study. No Phase 1 trial. Community protocols are empirical extrapolations from animal studies where HNG was administered at doses ranging from 0.5-4 mg/kg in mice — which would translate to roughly 3-25 mg for a 70 kg human via allometric scaling. Community doses of 0.5-2 mg are substantially below allometric equivalents. Whether they produce meaningful receptor activation in humans is unknown.
Most community users use HNG (S14G-Humanin) rather than native Humanin, for the same reason that most research uses HNG: native Humanin is weakly potent at practical doses. HNG's 1,000-10,000x potency advantage makes it the functional compound for exogenous use. This potency difference also means that HNG dose extrapolation from native Humanin research is not straightforward — the effective dose in mg may differ substantially. When purchasing 'Humanin' from a research vendor, confirm via COA mass spec which compound you are actually receiving.
Protocol
Compound
Dose
Frequency
Duration
Conservative / entry
HNG
0.5 mg SubQ
Weekly
4-8 weeks on, 4 weeks off
Standard community
HNG
1-2 mg SubQ
Weekly
4-8 weeks on, 4 weeks off
Animal research reference
HNG
0.5-4 mg/kg IP or SubQ
2x/week
Multiple months (middle-aged mice)
Weekly dosing (rather than daily) is the community standard — consistent with the animal research protocols where twice-weekly HNG produced the cognitive aging prevention data. This is also consistent with the peptide's half-life: HNG's plasma half-life is estimated at several hours, but its biological effects persist longer (likely through receptor-mediated gene expression changes that outlast the peptide's plasma presence).
No specific circadian timing requirement established for Humanin. No food dependency. Standard SubQ injection technique. Some community users prefer morning injection consistent with other longevity peptide protocols. The age-dependent signaling finding (old mice showed hippocampal AKT/ERK1/2 activation that young mice did not) suggests potential for more pronounced effects in older users — possibly an argument for more aggressive dosing in the 50+ population specifically. This is mechanistic inference, not dosing recommendation.
HNG: lyophilized powder. Reconstitute with bacteriostatic water. Minimize air exposure (Cys7 oxidation risk). Refrigerate at 2-8C; use within 30 days. Mass spectrometry confirming HNG molecular weight (~2,646 Da) is the identity check — native Humanin is approximately 2,689 Da; the difference is small but mass spec should confirm the S14G substitution is present. HPLC purity 98%+. Pricing 2026: research vendor, 1 mg HNG: $30-70; 5 mg HNG: $100-200.
No standard monitoring protocol for community Humanin/HNG use. The most interesting potential monitoring: plasma Humanin levels can be measured (Cohen's group used commercial ELISA kits; some specialty longevity labs offer this test). Monitoring whether exogenous HNG actually raises plasma Humanin levels — or whether the exogenous peptide is rapidly cleared without meaningful impact on circulating levels — would be the most direct test of whether the community protocol is pharmacologically active. This monitoring is not routine but is the most scientifically meaningful test available to community users.
HNG has an excellent safety profile in animal studies — no significant adverse effects documented at doses used in published research, including chronic 6-10 month treatment protocols in aging mice. Community safety reports are consistent with this: Humanin/HNG is described as one of the better-tolerated longevity peptides in community use. No serious adverse events reported in community self-experimentation. No published human safety study.
The IGFBP-3 neutralization mechanism raises a theoretical cancer concern in the same category as FOXO4-DRI's p53 mechanism — but with an important mitigating factor. FOXO4-DRI disrupts a core tumor suppressor mechanism (p53) directly. Humanin neutralizes IGFBP-3, which drives apoptosis in both normal and cancer cells. In a context where IGF-1 is also high (as in GH secretagogue users), the combination of high IGF-1 (pro-proliferative) + Humanin-mediated IGFBP-3 neutralization (reduced apoptosis) creates a theoretical pro-cancer environment at the cellular level. The Laron Syndrome counterargument (high Humanin + low IGF-1 = no cancer) applies in the low-IGF-1 context but may not apply in the high-IGF-1 context. For users combining Humanin with GH secretagogues: discuss the theoretical cancer concern with a physician. Active malignancy contraindication applies.
Not FDA-approved. Not PCAC-reviewed. Research chemical only. Not a controlled substance. Unlike MOTS-c (which received explicit WADA S4.4 prohibition), Humanin/HNG is not currently listed on the 2026 WADA Prohibited List. Athletes can currently use Humanin without known WADA violation — verify current status annually as the prohibited list evolves. The absence of a WADA ban does not constitute a safety or efficacy endorsement.
Humanin's stacking logic is more complex than any other compound in this book, because its IGF-1 inverse relationship creates genuine tension with the most popular longevity peptide protocol the community uses.
MOTS-c and Humanin are both encoded in the mitochondrial 16S rRNA gene. They activate different pathways: MOTS-c drives AMPK and metabolic flexibility; Humanin drives GP130/STAT3/Akt neuroprotection and anti-apoptotic signaling. Their mechanisms are genuinely non-redundant and address different dimensions of mitochondrial signaling. The combination is mechanistically coherent for a comprehensive mitochondrial-derived peptide protocol. Important note: MOTS-c is WADA S4.4 banned; Humanin is not currently banned. Athletes can use Humanin but not MOTS-c.
SS-31 addresses mitochondrial structure (cardiolipin). MOTS-c addresses metabolic signaling (AMPK). Humanin addresses secreted cytoprotective/neuroprotective signaling (GP130/STAT3/Akt). Three distinct mitochondrial mechanisms, genuinely non-redundant. The 'complete mitochondrial stack' concept in the advanced longevity community often includes all three. No controlled data on combination vs any single compound.
THIS COMBINATION REQUIRES A DECISION
Humanin is inversely regulated by IGF-1. CJC-1295 + Ipamorelin raises GH, which raises IGF-1, which likely suppresses endogenous Humanin by ~20% (based on Cohen's GH treatment data in humans). Exogenous HNG supplementation could compensate for this suppression — or could coexist with it differently than the endogenous regulation model predicts. The clinical question: does exogenous HNG produce the same signaling outcomes as endogenously elevated Humanin? This is uncharacterized. The protocol question: should a user who values Humanin's longevity associations run GH secretagogues and Humanin simultaneously (accepting that IGF-1 is suppressing endogenous Humanin but supplementing exogenously)? Or does the GH/IGF-1 elevation create a cellular context where exogenous HNG's IGFBP-3 neutralization has different risk/benefit than in a low-IGF-1 environment? These questions have no data. They need to be held, not ignored, when designing a longevity stack.
FOXO4-DRI selectively kills senescent cells by activating apoptosis through p53. Humanin is an anti-apoptotic compound that protects cells from apoptosis via Bax neutralization and Akt activation. These mechanisms are potentially antagonistic — if run simultaneously, Humanin's anti-apoptotic signaling could theoretically blunt FOXO4-DRI's senolytic activity by protecting senescent cells from the apoptotic signal FOXO4-DRI is trying to deliver. The sequencing logic from FOXO4-DRI's chapter applies here: run senolytics first, then cytoprotective/restorative compounds after the senolytic course. Do not combine Humanin with FOXO4-DRI in the same cycle.
Most community users report no immediate perceptible effect — consistent with a compound that works through gene expression changes and cell survival signaling rather than acute receptor stimulation. Some users report mild increases in energy or mental clarity within the first week.
Cognitive sharpness and mental clarity most commonly reported benefit. Some users report better sleep quality. Improved recovery from exercise occasionally noted.
The window where longevity-focused users point to as producing the most consistent subjective improvement. Sustained energy, mental performance, and mood stability. These are the most subjective and uncontrolled reports in the book.
No long-term community tracking data. The animal data showing cognitive aging prevention required 6-10 months of treatment in middle-aged mice. Human longevity benefits — if they exist — would operate on similar or longer timescales and would not be subjectively perceptible.
Because no human intervention trial exists, all timelines are community-derived.
Timeframe
Community-Reported (Grade E)
Days 1-7
Most community users report no immediate perceptible effect — consistent with a compound that works through gene expression changes and cell survival signaling rather than acute receptor stimulation. Some users report mild increases in energy or mental clarity within the first week.
Week 2-4
Cognitive sharpness and mental clarity most commonly reported benefit. Some users report better sleep quality. Improved recovery from exercise occasionally noted.
Month 1-3
The window where longevity-focused users point to as producing the most consistent subjective improvement. Sustained energy, mental performance, and mood stability. These are the most subjective and uncontrolled reports in the book.
Long-term (months+)
No long-term community tracking data. The animal data showing cognitive aging prevention required 6-10 months of treatment in middle-aged mice. Human longevity benefits — if they exist — would operate on similar or longer timescales and would not be subjectively perceptible.
Based on the evidence architecture: older adults (50+) with documented Humanin decline are the most pharmacologically rational population — consistent with the age-dependent signaling finding (old mice showed receptor pathway activation that young mice did not). Users with metabolic dysfunction, cardiovascular risk factors, or cognitive aging concerns have the most mechanistically grounded applications. The neuroprotection evidence specifically suggests users with family history or personal concern about neurodegenerative conditions as a potentially important target population.
Community standard: 4-8 weeks on, 4 weeks off. The animal research protocol (twice weekly for 6-10 months) used continuous administration rather than cycling. The rationale for cycling in community use: limit cumulative exposure to an unvalidated compound; allow assessment of on-cycle vs off-cycle baseline. The animal evidence does not specifically require cycling.
HNG is a less common research peptide than SS-31, MOTS-c, or BPC-157. Fewer vendors carry it; batch quality variation is higher. The S14G substitution must be confirmed by mass spectrometry — HPLC purity alone does not confirm the analog is HNG rather than native Humanin. Endotoxin testing below 0.1 EU/mg essential for injectable use. Pricing 2026: research vendor (HPLC + MS + endotoxin COA), 1 mg HNG: $30-70.
Humanin occupies a niche within the advanced mitochondrial longevity community — users who have typically already worked through MOTS-c, SS-31, and NAD+ protocols and are exploring the broader MDP family. The community is smaller than MOTS-c's community and more technically engaged. Community consensus on effects is modest — the most consistently reported benefit is subtle cognitive clarity improvement rather than dramatic observable changes. This modest community consensus is consistent with a compound that works on cellular survival and aging mechanisms rather than acute pharmacological activation.
The honest position on Humanin in 2026: one of the most compelling longevity biomarker stories in the aging literature — declining levels predict aging-related decline, centenarian offspring have more of it, the longest-lived mammals maintain it, the cancer-resistant Laron Syndrome population has 80% more than controls. And one of the most underutilized research opportunities in aging medicine — no human intervention trial, a small community using an analog of an endogenous mitochondrial peptide based on animal data and correlation studies. The IGF-1 inverse relationship is the most important complexity in this chapter and the least discussed in community discourse.
Research provenance: Humanin's literature has two distinct lineages — the neuroprotection literature (Nishimoto, Hashimoto in Japan; multiple independent US and European labs) and the aging/longevity literature (Cohen group at USC, formerly UCLA). The neuroprotection evidence has substantially more independent geographic distribution than most compounds in this book. The longevity correlations are more Cohen-concentrated. Both lineages are credible; the provenance concentration is lower than for Russian neuropeptides or single-lab compounds like Epitalon.
Hashimoto Y, Niikura T, Tajima H, et al. (2001) [1]. A rescue factor abolishing neuronal cell death by a wide spectrum of familial Alzheimer's disease genes and Aβ. Proc Natl Acad Sci USA. 98(11):6336-41. [THE discovery paper — Humanin identified from occipital cortex cDNA library; protects against AD-relevant insults; Keio University, Japan; multiple independent groups have replicated the core finding]
Cohen P, et al. (Aging, 2020). The mitochondrial derived peptide humanin is a regulator of lifespan and healthspan. doi:10.18632/aging.103534. [Humanin overexpression extends C. elegans lifespan via daf-16/FOXO; centenarian offspring have higher Humanin; naked mole-rat levels stable; age-related decline across species; Humanin transgenic mice; USC Davis School of Gerontology]
Yen K, Wan J, Mehta HH, et al. (Scientific Reports, 2018). Humanin Prevents Age-Related Cognitive Decline in Mice and is Associated with Improved Cognitive Age in Humans. 8:14212. doi:10.1038/s41598-018-32616-7. [HNG twice weekly prevents cognitive aging in middle-aged mice; human cognitive age association; multiple behavioral tests; Cohen group USC]
Wan J, Mehta HH, Merry TL, et al. (Aging Cell, 2014). IGF-I regulates the age-dependent signaling peptide humanin. doi:10.1111/acel.12243. PMC4172517. [THE IGF-1 inverse relationship paper: Pearson r = -0.69 with IGF-1 in GH-deficient children; GH treatment drops Humanin ~20%; Laron Syndrome = 80% higher Humanin; genetic longevity models with elevated Humanin all have low GH/IGF-1]
Zhai D, Luciano F, Zhu X, et al. (2005) [2]. Humanin binds and nullifies Bid activity by blocking its activation of Bax and Bak. J Biol Chem. [Bax/Bid binding mechanism; anti-apoptotic interaction; Reed group, Burnham Institute — INDEPENDENT of Nishimoto]
Guo B, et al. (Oncotarget, 2016). The mitochondrial derived peptide humanin activates the ERK1/2, AKT, and STAT3 signaling pathways and has age-dependent signaling differences in the hippocampus. PMC5216912. [GP130/WSX-1/CNTFR receptor complex activation; JAK/STAT3/AKT/ERK pathways; age-dependent signaling difference in hippocampus — old mice respond, young do not; Cohen group]
Muzumdar RH, Huffman DM, Atzmon G, et al. (PLoS ONE, 2009). Humanin: a novel central regulator of peripheral insulin action. PMC2709436. [Humanin improves insulin sensitivity; plasma decline with age in humans; HN analog lowers blood glucose in diabetic rats; INDEPENDENT — Barzilai group at Einstein College of Medicine]
Widmer RJ, Flammer AJ, Herrmann J, et al. (Am J Physiol Heart Circ Physiol, 2013). Circulating humanin levels are associated with preserved coronary endothelial function. doi:10.1152/ajpheart.00765.2012. [INDEPENDENT — Mayo Clinic cardiovascular group; human observational; higher Humanin correlates with better endothelial function]
PMC10740898. (2023) [3]. Neuroprotective Action of Humanin and Humanin Analogues: Research Findings and Perspectives. [Comprehensive review of HN neuroprotection literature; covers all major mechanisms and applications; full literature survey through 2023]
Humanin is the mitochondrial peptide that told us mitochondria are endocrine organs. Its discovery was more revolutionary than its community discourse reflects. The longevity correlations are among the most compelling in aging biology. And the IGF-1 inverse relationship is the most consequential underappreciated fact in the longevity peptide space.
The central tension resolved: Humanin levels decline with age in every species studied. People whose parents and grandparents lived to 100+ have more of it than their peers. The longest-lived mammal (naked mole-rat) maintains it throughout its exceptional lifespan. People with genetic mutations that suppress IGF-1 — who have low cancer rates and extended healthspan — have 80% more of it. And the compound that produced the highest circulating levels in a human intervention wasn't longevity-focused at all: it was GH treatment, which drops Humanin by ~20%. The standard community GH secretagogue protocol likely suppresses endogenous Humanin. Whether this matters, and whether exogenous HNG compensates for it, is the most important unanswered protocol question in the mitochondrial longevity stack.
The strongest argument for Humanin: the evidence architecture is more distributed than most longevity compounds. Neuroprotection against Aβ has been confirmed in multiple independent labs across multiple countries. The cardiovascular correlation is from the Mayo Clinic, not Cohen's group. The metabolic data is from Barzilai's group at Einstein. The longevity correlation is from Cohen's group but uses multiple independent species and human cohort designs that are methodologically credible. The C. elegans lifespan extension is well-documented and autophagy-dependent — one of the most conserved longevity pathways in biology. Humanin is not a Khavinson-type single-source compound.
The strongest argument for caution: no human intervention trial exists. The centenarian correlation is compelling but observational. The IGF-1 inverse relationship makes the pharmacological context of supplementing HNG in a high-IGF-1 environment (GH secretagogue users) different from the low-IGF-1 environment where high Humanin is associated with longevity. And the IGFBP-3 neutralization mechanism creates a theoretical cancer concern that is different in character depending on the IGF-1 context.
Humanin is the mitochondrial peptide that told us mitochondria are endocrine organs. Its discovery was more revolutionary than its community discourse reflects. The longevity correlations are among the most compelling in aging biology. And the IGF-1 inverse relationship is the most consequential underappreciated fact in the longevity peptide space.
The central tension resolved: Humanin levels decline with age in every species studied. People whose parents and grandparents lived to 100+ have more of it than their peers. The longest-lived mammal (naked mole-rat) maintains it throughout its exceptional lifespan. People with genetic mutations that suppress IGF-1 — who have low cancer rates and extended healthspan — have 80% more of it. And the compound that produced the highest circulating levels in a human intervention wasn't longevity-focused at all: it was GH treatment, which drops Humanin by ~20%. The standard community GH secretagogue protocol likely suppresses endogenous Humanin. Whether this matters, and whether exogenous HNG compensates for it, is the most important unanswered protocol question in the mitochondrial longevity stack.
The strongest argument for Humanin: the evidence architecture is more distributed than most longevity compounds. Neuroprotection against Aβ has been confirmed in multiple independent labs across multiple countries. The cardiovascular correlation is from the Mayo Clinic, not Cohen's group. The metabolic data is from Barzilai's group at Einstein. The longevity correlation is from Cohen's group but uses multiple independent species and human cohort designs that are methodologically credible. The C. elegans lifespan extension is well-documented and autophagy-dependent — one of the most conserved longevity pathways in biology. Humanin is not a Khavinson-type single-source compound.
The strongest argument for caution: no human intervention trial exists. The centenarian correlation is compelling but observational. The IGF-1 inverse relationship makes the pharmacological context of supplementing HNG in a high-IGF-1 environment (GH secretagogue users) different from the low-IGF-1 environment where high Humanin is associated with longevity. And the IGFBP-3 neutralization mechanism creates a theoretical cancer concern that is different in character depending on the IGF-1 context.
Feature
Humanin / HNG
MOTS-c
Gene location
MT-RNR2 (16S rRNA)
MT-RNR2 (16S rRNA) — same gene region
Primary mechanism
GP130/STAT3/Akt neuroprotection; Bax/IGFBP-3 neutralization; autophagy
AMPK activation via AICAR; nuclear translocation; metabolic reprogramming
Primary application
Neuroprotection; longevity biomarker; cytoprotection
Exercise mimicry; insulin sensitivity; metabolic optimization
Analog situation
HNG is 1,000-10,000x more potent than native Humanin; most research uses HNG
MOTS-c is used directly; no major potency-enhanced analog
Human evidence
Observational: aging decline confirmed; centenarian offspring correlation; IGF-1 inverse confirmed in humans
Observational: aging decline; marathon runner correlation; no intervention trial
Animal evidence
Multiple independent labs; C. elegans lifespan extension; cognitive aging prevention in mice
Multiple labs; exercise performance; metabolic syndrome
WADA status
Not currently listed
S4.4 explicit ban
IGF-1 relationship
Inversely regulated — IGF-1 suppresses Humanin
Not directly linked to IGF-1 axis
Community dose
0.5-2 mg HNG SubQ weekly
5-10 mg SubQ 2-3x/week
— End of Humanin —
THE PEPTIDE BIBLE | Humanin (HNG) | For Research & Educational Purposes Only
Humanin (HN) is a 24-amino acid peptide, sequence MAPRGFSCLLLLTSEIDLPVKRRA, molecular weight ~2,689 Da, encoded within the MT-RNR2 gene (mitochondrial 16S rRNA) of the mitochondrial genome. The first mitochondrial-derived peptide (MDP) ever identified. Discovered in 2001 by Nishimoto et al. during a screen for neuroprotective genes in the surviving occipital cortex of an Alzheimer's patient. Its discovery established that mitochondria are endocrine organelles producing secreted signaling peptides — the paradigm from which MOTS-c and the SHLP family followed. The critical analog: HNG (S14G-Humanin) — serine at position 14 replaced by glycine — is 1,000-10,000x more potent than native Humanin. Most published research uses HNG. Most commercial research peptide is HNG. Verify via mass spec (HNG MW ~2,646 Da; native Humanin ~2,689 Da). Primary mechanisms: extracellular — GP130/WSX-1/CNTFR tripartite receptor complex activation → JAK/STAT3, PI3K/Akt, ERK1/2 pro-survival cascades; intracellular — physical binding and neutralization of Bax (pro-apoptotic) and IGFBP-3 (apoptotic driver independent of IGF-1); secondary receptor FPR2 → anti-inflammatory effects; chaperone-mediated autophagy activation (longevity-relevant pathway). Age-related decline: documented in humans, mice, and rats — from ~200-300 ng/mL in young adults to ~80-100 ng/mL by the sixth or seventh decade. Human longevity correlations (Cohen group, Aging 2020): centenarian offspring have significantly higher plasma Humanin than age-matched controls; naked mole-rats maintain stable Humanin throughout exceptional lifespan; Humanin lower in Alzheimer's disease and MELAS patients. C. elegans lifespan extension via Humanin overexpression — autophagy and daf-16/FOXO dependent. IGF-1 INVERSE RELATIONSHIP (the chapter's most important finding): Humanin and IGF-1 are inversely regulated. Pearson r = -0.69 (Humanin vs IGF-1 in GH-deficient children). GH treatment drops Humanin ~20%. Laron Syndrome patients (GH receptor deficiency, very low IGF-1, near-zero cancer incidence) have 80% HIGHER Humanin than matched controls. All long-lived animal models with GH/IGF-1 pathway mutations have elevated Humanin. The GH secretagogue protocols the community uses to raise IGF-1 likely suppress endogenous Humanin. Human evidence: purely observational — no intervention trial registered or completed. Animal evidence: neuroprotection against Aβ (multiple independent labs), cognitive aging prevention (Scientific Reports 2018), cardiovascular protection (Mayo Clinic independent observational), metabolic improvement (Barzilai group independent). Community dosing: 0.5-2 mg HNG SubQ weekly. FDA: not approved; research chemical; not PCAC-reviewed. WADA: not currently listed (unlike MOTS-c which is S4.4 banned). Active malignancy contraindication: IGFBP-3 neutralization + pro-survival Akt/STAT3 signaling warrants oncologist discussion.
A Structural Modification of Semax With No Published Studies of Its Own. Being Sold as 'The Most Potent Semax Analog.' Every Claim Belongs to Its Parent Compound.
The Compound That Raises NAD+ By Stopping the Body From Destroying It. NNMT: The Enzyme That Wastes Nicotinamide. Fat Loss Without Food Restriction in Mice. The Neelakantan Group's Research Tool Repurposed as a Longevity Drug. Zero Human Trials. 100 mg/Day Community Dose Extrapolated From Mouse IP Injections. The 1-MNA Question: The Metabolite You're Blocking Has Protective Roles in Liver and Kidney. A 2025 Cell/TPS Review Calls for Clinical Translation. Clinics Already Prescribing It Without FDA Ruling on Safety.
Six Human Clinical Trials. 900+ Participants. Safety Indistinguishable From Placebo. Primary Fat Loss Endpoint Failed. WADA Banned. FDA Rejected for Compounding. The Community Uses It Anyway at Doses That Never Worked in the Trials.