Humanin: The First Mitochondrial-Derived Peptide — A 2026 Research Guide

Humanin occupies an unusual place in molecular biology: it was the peptide that forced researchers to reconsider what the mitochondrial genome actually encodes. Identified in 2001 from a small open reading frame inside the mitochondrial 16S ribosomal RNA region, humanin became the founding member of a class now called mitochondrial-derived peptides (MDPs) — short bioactive sequences transcribed from mtDNA rather than the nuclear genome. In the years since, it has become one of the most-cited model systems for studying cytoprotective and stress-response signaling in cell and animal work. This guide summarizes the molecular profile, the receptor and pathway-level mechanism, and the published preclinical literature as they stand in 2026.

The information below describes in-vitro and preclinical laboratory research only. It is not medical guidance, and none of the findings described here establish safety or efficacy in humans.

Section 1 — Molecular Profile

Humanin is a 24-amino-acid peptide. Its full sequence, written in single-letter notation, is MAPRGFSCLLLLTSEIDLPVKRRA (Met-Ala-Pro-Arg-Gly-Phe-Ser-Cys-Leu-Leu-Leu-Leu-Thr-Ser-Glu-Ile-Asp-Leu-Pro-Val-Lys-Arg-Arg-Ala). The sequence contains a single cysteine residue that is important to several of its documented interactions, and a hydrophobic core that governs its self-association behavior in solution.

Key identifiers used in the literature and in analytical characterization:

• Compound name: Humanin (HN); the potency-enhanced analog is S14G-Humanin (HNG)
• CAS number: 330936-69-1
• Molecular formula: C₁₁₉H₂₀₄N₃₄O₃₂S₂
• Molecular weight: ~2687.2 g/mol
• Genomic origin: small ORF within the mitochondrial 16S rRNA region (MT-RNR2)
• Class: mitochondrial-derived peptide (MDP)

A widely studied variant, S14G-humanin (HNG), carries a single serine-to-glycine substitution at position 14 and is reported in the literature to display markedly greater potency in cell-based cytoprotection assays than the native sequence. Both native humanin and HNG appear across the published record, so the specific analog matters when interpreting any preclinical result.

Section 2 — Mechanism

Humanin is studied primarily as a cytoprotective signaling peptide, and the mechanistic literature converges on three linked lines of activity, all described here strictly at the pathway and receptor level.

Bax antagonism. The most structurally detailed mechanism is direct interaction with Bax, a pro-apoptotic Bcl-2-family protein. In the model established by Guo and colleagues, humanin binds Bax and prevents its translocation from the cytosol to the mitochondrial membrane, blocking the membrane permeabilization step that would otherwise release cytochrome c. Later work extended this to Bid, describing reduced mitochondrial membrane association and oligomerization of both proteins in vitro.

Receptor-mediated STAT3 signaling. Extracellularly, humanin has been studied as a ligand for a trimeric receptor complex involving gp130 (IL6ST) together with CNTFR and WSX-1. Engagement of this complex is associated in the literature with activation of the JAK/STAT3 pathway, and separately with ERK1/2 and AKT signaling. A study in hippocampal tissue reported that humanin activates ERK1/2, AKT, and STAT3 with age-dependent differences in signaling intensity — a finding frequently cited in MDP and aging research.

IGF axis modulation. Humanin also binds insulin-like growth factor binding protein 3 (IGFBP-3), and this interaction has been described as bidirectional: the two molecules co-regulate cell-survival and apoptotic readouts in cell models, and IGFBP-3 influences the clearance kinetics of humanin in animal studies. This places humanin at an intersection between the classic IGF signaling axis and the mitochondrial stress-response program.

Throughout the literature these mechanisms are described as things humanin has been studied for and researched for in defined experimental systems — not as demonstrated clinical effects.

Section 3 — Preclinical Research Data

The preclinical dataset for humanin is unusually broad for a peptide of its size, spanning neuronal, metabolic, cardiovascular, and cellular-senescence models.

In neuronal work, humanin and HNG have been used extensively as tool compounds in amyloid-beta toxicity models, where they reduce apoptotic readouts in cultured cells. In metabolic models, humanin and related MDPs have been characterized as age-dependent regulators of apoptosis, insulin sensitivity, and inflammatory markers, with circulating levels reported to decline with age in several species. In vascular and cellular-senescence systems, MDPs including humanin have been studied for their effects on stress-response pathways and mitochondrial function.

An important theme in the 2016–2026 literature is that humanin is not an isolated curiosity. The same mtDNA region encodes a family of small humanin-like peptides (SHLPs), and MOTS-c is encoded elsewhere in the mitochondrial genome. Studying humanin has therefore become a gateway into the broader question of how the mitochondrion signals to the rest of the cell — a research area PYXAX has covered separately in its work on MOTS-c and SS-31.

None of these datasets constitute evidence of a therapeutic effect in humans. They describe measured changes in defined in-vitro and animal systems, which is the appropriate frame for interpreting them.

Section 4 — Published Literature

The following are real, published papers that anchor the humanin research record. Researchers should consult the primary sources directly rather than relying on summaries.

• Hashimoto Y, et al. (2001). “A rescue factor abolishing neuronal cell death by a wide spectrum of familial Alzheimer’s disease genes and Aβ.” PNAS 98(11):6336–6341. The original identification of humanin as a neurosurvival factor.
• Guo B, et al. (2003). “Humanin peptide suppresses apoptosis by interfering with Bax activation.” Nature 423:456–461. The landmark Bax-antagonism mechanism.
• Ikonen M, et al. (2003). “Interaction between the Alzheimer’s survival peptide humanin and insulin-like growth factor-binding protein 3 regulates cell survival and apoptosis.” PNAS 100(22):13042–13047.
• Lee C, Yen K, Cohen P (2013). “Humanin: a harbinger of mitochondrial-derived peptides?” Trends in Endocrinology & Metabolism 24(5):222–228. A foundational review of the MDP concept.
• Cobb LJ, et al. (2016). “Naturally occurring mitochondrial-derived peptides are age-dependent regulators of apoptosis, insulin sensitivity, and inflammatory markers.” Aging (Albany NY) 8(4):796–809. Introduces the SHLP family alongside humanin.
• Zhang X, et al. (2017). “Humanin decreases mitochondrial membrane permeability by inhibiting the membrane association and oligomerization of Bax and Bid proteins.” Acta Pharmacologica Sinica 39:220–229.

Together these span the discovery, the core mechanism, the IGFBP-3 axis, and the modern MDP framework, and they are the citations most worth reading in full before designing new experiments.

Section 5 — Research Applications

In laboratory settings, humanin is used chiefly as a reference or tool compound. Reported in-vitro applications include serving as a positive control in apoptosis and Bax-translocation assays; as a probe for gp130/STAT3, ERK1/2, and AKT pathway activation in cultured cells; as a comparator in studies of the broader MDP and SHLP family; and as a model ligand for investigating IGFBP-3 interactions. In animal research it appears as an intervention in neuronal-stress and metabolic models, often alongside its more potent HNG analog.

Because the native peptide and the HNG analog behave differently in potency terms, careful documentation of which sequence, which lot, and which purity grade was used is essential to reproducibility. These are the details that separate a citable result from an uninterpretable one. Reconstitution behavior is another practical consideration: humanin’s hydrophobic core drives self-association in aqueous buffers, so solubility conditions and handling should be recorded as part of the experimental methods, and stock concentrations verified rather than assumed.

The peptide’s dual identity as both an intracellular Bax antagonist and an extracellular gp130 ligand also means the experimental readout depends heavily on how the compound is delivered in a given system. Studies using intracellular expression, extracellular application, and stabilized analogs are not always directly comparable, and that distinction is worth tracking when assembling a literature base for a new project.

Section 6 — How to Evaluate a Source

Peptide characterization is only as good as the analytical data behind it, and for a research-grade compound the certificate of analysis (COA) is the document that matters. When evaluating any humanin source, a researcher should confirm:

• Identity by mass spectrometry (LC-MS), matching the expected ~2687 g/mol mass and the MAPRGFSCLLLLTSEIDLPVKRRA sequence — and, critically, distinguishing native humanin from the S14G (HNG) analog, since the two are easy to conflate.
• Purity by HPLC, with a stated percentage and a visible chromatogram rather than a bare number.
• Endotoxin testing (USP <85> LAL), which matters for any cell-based work.
• Heavy metals by ICP-MS.
• Lot-specificity: the COA should correspond to the exact batch shipped, be dated, and name the accredited laboratory that performed the testing.

A supplier that cannot produce a lot-matched COA naming its testing lab has not given you enough to trust the material. As a pricing reference point, humanin in 2026 typically lists in the range of roughly $50–90 per 10 mg vial at retail, with lower per-milligram costs on bulk lots — but price should never substitute for analytical verification.

Section 7 — The PYXAX Verification Standard

PYXAX uses accredited independent laboratories in its verification network, including ILS Labs, Krause Analytical, and Janoshik. The current per-batch panel covers purity by HPLC, potency against label claim, and identity by LC-MS. A lot-specific COA is published in the COA Library before dispatch and names the laboratory that tested that batch. Endotoxin, heavy-metals, and final-vial sterility screening are not part of the current panel.

Founding batches are documented end to end, and full analytical data files are available per lot. You can review current documentation in the COA library, read the underlying methodology on the verification standard page, or browse the full catalog in the shop.

All PYXAX compounds are supplied strictly for in-vitro and preclinical laboratory research use only. Not for human consumption. Not for veterinary use. Not for diagnostic procedures. These statements have not been evaluated by the FDA. Researchers are responsible for compliance with all applicable laws and regulations governing the use of research compounds in their jurisdiction.