This section contains detailed information on peptide compounds intended for research and educational purposes only.
Peptide category
Signalling Peptides
Short peptide sequences associated with signalling and matrix-related research pathways.
21 profiles
About this category
Signalling peptides are typically reviewed for their interactions with cell surface receptors, intracellular markers, and matrix-associated processes. Studies in this category usually focus on observation of pathway activity within controlled laboratory systems.
AHK-Cu
Signalling Peptides
Copper-binding tripeptide (Ala-His-Lys) studied alongside GHK-Cu in skin and hair research
AHK-Cu is a copper-binding tripeptide (Ala-His-Lys) sometimes paired with GHK-Cu in skin and hair research. The peer-reviewed literature directly on AHK / AHK-Cu is more limited than on GHK / GHK-Cu, and several papers focus on the related DAHK (Asp-Ala-His-Lys) human-serum-albumin N-terminal sequence rather than AHK itself.
Limited primary literature; documented as part of the broader copper-tripeptide research alongside GHK-Cu
ARA-290 (cibinetide) is an 11-residue peptide derived from the helix B domain of erythropoietin. It engages the innate-repair receptor (a heterodimer of EPO-R and β common receptor) without stimulating erythropoiesis. Phase II clinical evidence exists in small-fibre neuropathy contexts; it is investigational at the time of writing.
Phase II clinical evidence in sarcoidosis small-fibre neuropathy and diabetic neuropathy; investigational
Khavinson short peptide · Ala-Glu-Asp tripeptide · Preclinical only
Cartalax is a short tripeptide (Ala-Glu-Asp / AED) developed by the Khavinson research group in St Petersburg. Published evidence is preclinical, primarily organotypic and cell-culture work, and is concentrated within the Khavinson network. There are no FDA, MHRA, or EMA approvals.
Preclinical (cell-culture) literature from a single research network
Neuropeptide / amino-acid mixture derived from porcine brain tissue · Approved in multiple jurisdictions (not US/UK); Cochrane evidence is mixed
Cerebrolysin (FPF1070) is a porcine-brain-derived peptide and free-amino-acid mixture marketed by Ever Neuro Pharma. It is approved in many countries (including parts of Europe and Asia) for stroke, traumatic brain injury, and dementia, but is not FDA-approved in the United States. Multiple Cochrane systematic reviews have evaluated the evidence base — the most recent stroke update (2023) reports no mortality benefit and a possible increase in non-fatal serious adverse events.
Multiple Cochrane systematic reviews in stroke and vascular dementia; clinical evidence is mixed
Dermorphin is a seven-residue opioid peptide isolated from the skin of South American Phyllomedusa frogs in the 1980s. It is a highly selective μ-opioid receptor agonist and is approximately 30–40 times more potent than morphine in animal models. Dermorphin and its analogues are research compounds; the parent compound has documented illicit use in horse racing and is treated as a controlled substance for veterinary and anti-doping purposes.
Pharmacology and structure-activity literature from the 1980s onwards; analogue development for analgesia research
Endogenous nonapeptide implicated in delta-sleep induction
DSIP (delta sleep-inducing peptide) is an endogenous nine-residue peptide isolated from rabbit cerebral venous blood during electrical sleep stimulation in the 1970s. Most of the peer-reviewed literature consists of reviews and early-phase research from the 1970s–2000s; modern controlled clinical trials are limited.
Foundational review and early-phase literature from 1970s–2000s; limited recent peer-reviewed primary research
Glycyl-L-histidyl-L-lysine — endogenous tripeptide (uncomplexed form of GHK-Cu)
GHK is the uncomplexed tripeptide form of GHK-Cu — the same sequence (Gly-His-Lys) without bound copper. It is endogenously present in human plasma and declines markedly with age. Most published research discusses GHK in the copper-bound (GHK-Cu) form because the copper binding is central to the proposed mechanisms; this profile distinguishes the uncomplexed peptide for completeness.
Mostly in vitro and topical-formulation literature; serum-level decline with age documented
GHK-Cu is a copper-binding tripeptide complex studied across in vitro, rodent, and topical-cosmetic models, primarily in the context of extracellular matrix and skin biology research.
Kisspeptin-10 is a C-terminal fragment of the KISS1 gene product that activates the KISS1R (GPR54) receptor. Published research spans cell-based signalling assays, knockout-mouse models, and human reproductive-endocrinology pharmacology studies, alongside emerging bone-biology research.
Receptor signalling and reproductive endocrinology literature
C-terminal tripeptide of α-melanocyte-stimulating hormone (α-MSH 11-13)
KPV is the C-terminal tripeptide fragment of α-melanocyte-stimulating hormone (α-MSH). Research has demonstrated anti-inflammatory activity in models of intestinal inflammation (colitis) and keratinocyte biology, with the PepT1 transporter implicated in cellular uptake.
Active in vitro and rodent inflammation literature; in vivo colitis models and dermatology research
Human cathelicidin antimicrobial peptide (C-terminal cleavage of hCAP-18)
LL-37 is the C-terminal 37-residue active fragment of the human cathelicidin precursor hCAP-18. It is an endogenous antimicrobial and immunomodulatory peptide expressed by neutrophils, macrophages, and epithelial cells. The peer-reviewed literature is large and includes antimicrobial, anti-HIV, and host-defence research.
Extensive in vitro / animal antimicrobial and immunomodulatory literature; early-phase human studies in skin and infection contexts
Melanotan-1 (afamelanotide) is a synthetic 13-residue analogue of α-melanocyte-stimulating hormone (α-MSH) with substitutions that improve potency and stability. It is FDA-approved as Scenesse (Clinuvel Pharmaceuticals) for the prevention of phototoxicity in adult patients with a history of phototoxic reactions from erythropoietic protoporphyria (EPP).
FDA-approved for erythropoietic protoporphyria (2019); EU approval for EPP earlier; additional research in vitiligo and other photodermatoses
Synthetic cyclic α-MSH analogue · Not approved for human use in any jurisdiction
Melanotan-2 is a synthetic cyclic seven-residue analogue of α-melanocyte-stimulating hormone (α-MSH) that activates multiple melanocortin receptors (notably MC4R). It is not approved as a medicine in any jurisdiction. PT-141 (bremelanotide) was developed from the same cyclic scaffold but is a distinct, separately-approved compound.
Preclinical animal pharmacology; documented adverse-event case reports in unregulated human use
Mitochondrial-derived peptide (mitochondrial 12S rRNA open reading frame product)
MOTS-c is a 16-residue peptide encoded within the mitochondrial 12S rRNA open reading frame, discovered in 2015. It has been studied in metabolic homeostasis, insulin resistance, and skeletal muscle research. All cited primary studies on this profile are preclinical (mouse and cell models).
Active preclinical literature (mouse and cell models); no controlled human clinical trials at time of writing
Khavinson short peptide · Glu-Asp-Arg tripeptide · Preclinical only
Pinealon is a short tripeptide (Glu-Asp-Arg / EDR) developed by the Khavinson research group at the St Petersburg Institute of Bioregulation and Gerontology. Published evidence is preclinical — rodent in vivo and cell-culture studies — and is concentrated within the Khavinson network. There are no FDA, MHRA, or EMA approvals.
Preclinical (rodent and cell-culture) literature from a single research network
Melanocortin receptor agonist · FDA-approved (Vyleesi, as bremelanotide)
PT-141 (bremelanotide) is a cyclic heptapeptide melanocortin receptor agonist derived from α-melanocyte-stimulating hormone (α-MSH). It is FDA-approved as Vyleesi for acquired, generalised hypoactive sexual desire disorder (HSDD) in premenopausal women. Approval is indication-specific.
Phase III clinical evidence; FDA-approved (Vyleesi) for hypoactive sexual desire disorder in premenopausal women
Semax is a synthetic heptapeptide derived from ACTH(4–7), most extensively characterised in rodent models of cerebral ischaemia and in vitro neurobiology assays. Approved in the Russian Federation as a research and clinical compound; not approved for human therapeutic use in the United States, United Kingdom, or European Union.
SS-31 (elamipretide, MTP-131) is a mitochondria-targeted synthetic tetrapeptide developed by Szeto and Schiller. It concentrates in the inner mitochondrial membrane and interacts with cardiolipin to support electron transport and reduce reactive oxygen species. It has been studied in multiple late-phase clinical trials (Barth syndrome, primary mitochondrial myopathy, age-related macular degeneration, heart failure) but is not FDA-approved at the time of writing.
Multiple Phase II–III clinical trials (Barth syndrome, primary mitochondrial myopathy, dry AMD, heart failure); not FDA-approved at time of writing
Thymalin is a peptide complex extracted from calf thymus tissue, developed and characterised by the Khavinson group in St Petersburg, Russia. It is registered as a preparation in the Russian Federation. The peer-reviewed literature consists predominantly of work from the Khavinson group and collaborators across cellular ageing, immunology, and pineal-thymus axis research.
Khavinson-group experimental and observational literature spanning four decades; limited independent replication outside the originating research network
Synthetic 28-residue immunomodulatory peptide · Approved in multiple jurisdictions (not FDA-approved in the US)
Thymosin Alpha-1 (Tα1, thymalfasin, marketed as Zadaxin) is a synthetic 28-residue immunomodulatory peptide based on a thymic peptide fragment. It is approved in many jurisdictions (including Italy and China) for chronic hepatitis B and as an immunomodulator, and remains unapproved by the FDA in the United States. The most recent Phase III data (Wu 2025, BMJ) examined sepsis.
Phase III clinical evidence including sepsis (BMJ 2025); approved in Italy, China, and other jurisdictions for hepatitis B/C and as an immunomodulator
VIP is an endogenous 28-residue neuropeptide discovered in the 1970s. It functions as a neurotransmitter, vasodilator, and immunomodulator. Most published research is mechanistic (cell biology, animal physiology) or focused on VIP-secreting tumours (VIPomas); a smaller body of clinical research has explored VIP and its analogues in pulmonary, inflammatory, and cancer-targeting contexts.
Extensive endogenous-physiology and pathophysiology literature; small clinical trials in pulmonary and inflammatory disease
