Peptide Database

Trappin-2 · SKALP

Elafin is an endogenous serine protease inhibitor (serpin-like) peptide produced by epithelial cells at mucosal surfaces. It inhibits neutrophil elastase and proteinase 3, protecting tissues from excessive inflammatory damage, while also exhibiting direct antimicrobial activity against bacteria and fungi. Research focuses on inflammatory bowel disease, cystic fibrosis, ARDS, and vaginal microbiome modulation, where recombinant elafin is in Phase 2 trials.

ET-1 · Big endothelin-1

Endothelin-1 (ET-1) is a 21-amino-acid vasoconstrictor peptide produced primarily by vascular endothelial cells. It is the most potent endogenous vasoconstrictor known, acting through ETA and ETB receptors on vascular smooth muscle and endothelium. Elevated ET-1 is implicated in pulmonary arterial hypertension, heart failure, and renal disease — driving the development of endothelin receptor antagonists (bosentan, ambrisentan, macitentan) as clinical drugs.

Leu-Enkephalin · Met-Enkephalin

Enkephalins are endogenous opioid pentapeptides (Met-enkephalin and Leu-enkephalin) acting as natural ligands for delta and mu opioid receptors. They modulate pain, mood, reward, and immune function. Low-dose naltrexone (LDN) works partly by transiently blocking opioid receptors to upregulate enkephalin production. Methionine enkephalin (met-enkephalin) has shown immune-modulating and anti-tumor properties in research, particularly for HIV and cancer.

Epitalon · Epithalamin

Epithalon is a synthetic tetrapeptide (Ala-Glu-Asp-Gly) modeled on the endogenous pineal peptide epithalamin. It is one of the most extensively studied longevity peptides, with Russian research demonstrating telomerase activation, telomere elongation, melatonin normalization, and extended lifespan in animal models. Long-term human studies show reduced all-cause mortality rates and improved biomarkers of aging.

Byetta · Bydureon

Exenatide is a GLP-1 receptor agonist derived from exendin-4, a peptide found in Gila monster saliva. The first GLP-1 RA approved for type 2 diabetes, it established the GLP-1 drug class. Extended-release formulations (Bydureon) allow once-weekly dosing. Emerging research explores repurposing for Parkinson's disease, where small trials show motor improvement, and Alzheimer's disease neuroprotection.

FGF-21

FGF-21 is a 181-amino-acid endocrine fibroblast growth factor secreted by the liver under fasting conditions. It promotes fatty acid oxidation, ketogenesis, insulin sensitization, and thermogenesis in brown adipose tissue. Animal studies show it extends lifespan and reverses metabolic syndrome. Long-acting FGF-21 analogs and fusion proteins (efruxifermin, pegbelfermin) are in Phase 2–3 trials for NASH, type 2 diabetes, and dyslipidemia.

FST-344 · Follistatin isoform 344

Follistatin-344 is an isoform of follistatin, an endogenous glycoprotein that binds and neutralizes myostatin (GDF-8) and activin, thereby releasing the natural inhibition on muscle growth. Without myostatin's inhibitory signal, satellite cells proliferate and muscle fiber hypertrophy is dramatically enhanced. Gene therapy studies in animals and in rare myostatin-null humans demonstrate extreme muscle mass increases, driving significant research interest.

Proxofim

FOXO4-DRI is a D-retro-inverso peptide that disrupts the interaction between FOXO4 and p53 in senescent cells, triggering selective apoptosis of senescent cells (senolysis) while leaving healthy cells unaffected. Mouse studies demonstrated restoration of fitness, fur density, and renal function after treatment. It represents a first-in-class peptide senolytic, establishing proof-of-concept for peptide-mediated clearance of the senescent cell burden.

HGH Frag 176-191 · Growth Hormone Fragment 176-191

Fragment 176-191 is the C-terminal amino acid sequence 176–191 of human growth hormone, closely related to AOD-9604. It mimics the lipolytic activity of natural GH without binding to the GH receptor, thus avoiding insulin resistance and proliferative effects. Research shows it reduces fat mass in animal models by enhancing fat metabolism and inhibiting new fat formation.

GAL

Galanin is a 29-30 amino acid neuropeptide widely distributed throughout the CNS and peripheral nervous system. It modulates memory, mood, pain, seizures, appetite, and sleep via three receptor subtypes (GALR1–3). Research focuses on its roles in Alzheimer's disease (galanin hyperinnervation of cholinergic neurons), depression, epilepsy, and eating behavior. Both agonists and antagonists have therapeutic potential depending on the target condition.

Growth Differentiation Factor 11 · Bone Morphogenetic Protein 11

GDF-11 is a member of the TGF-β superfamily that generated significant excitement when studies reported it as a "rejuvenating factor" in young parabiosis mouse blood. Subsequent research has been highly contested — some studies suggest it reverses cardiac hypertrophy and restores skeletal muscle and neural stem cell function in aged mice, while others find it increases with age and impairs muscle regeneration. It remains one of the most debated factors in aging biology.

Copper Peptide GHK · Glycyl-L-histidyl-L-lysine copper

GHK-Cu is a naturally occurring copper-binding tripeptide found in human plasma, saliva, and urine. Research demonstrates it stimulates collagen, elastin, and glycosaminoglycan synthesis, promotes wound healing, reduces inflammation, and activates protective antioxidant genes. Plasma levels decline with age, making it a significant anti-aging research target.

C₁₄H₂₄CuN₆O₄ · 340.84 Da (free ligand)

Motilin-related peptide · Growth hormone secretagogue

Ghrelin is a 28-amino-acid acylated peptide hormone primarily produced by gastric X/A-like cells and is the endogenous ligand for the growth hormone secretagogue receptor (GHS-R1a). It stimulates GH release, increases appetite and food intake, promotes energy storage, and modulates sleep and mood. Research explores ghrelin axis manipulation for obesity, cachexia, heart failure, and neurodegenerative diseases.

Growth Hormone-Releasing Hormone · Somatoliberin

GHRH is the endogenous 44-amino-acid hypothalamic peptide that drives the pulsatile secretion of growth hormone from the anterior pituitary. Native GHRH acts through GHRHR, stimulating GH gene transcription and secretion. It has a very short half-life in vivo, making it impractical as a therapeutic — which drove the development of modified analogs like sermorelin, CJC-1295, and tesamorelin. Research into GHRH receptor signaling underpins the entire GH secretagogue drug class.

Pralmorelin · Growth Hormone-Releasing Peptide 2

GHRP-2 is a synthetic hexapeptide and potent ghrelin receptor agonist that stimulates growth hormone release from the pituitary. It produces a strong GH pulse with some elevation of cortisol and prolactin at higher doses. Research includes GH deficiency diagnosis, body composition, sleep quality, and appetite stimulation via its ghrelin-mimetic mechanism.

C₄₅H₅₅N₉O₆ · 817.99 Da

Growth Hormone-Releasing Peptide 6 · His-DTrp-Ala-Trp-DPhe-Lys-NH₂

GHRP-6 is one of the original synthetic GHRPs, acting as a strong ghrelin receptor agonist. It produces robust GH release accompanied by significant appetite stimulation — a property that makes it both valuable for cachexia research and distinct from cleaner GHRPs like Ipamorelin. Research also shows cytoprotective and cardioprotective properties independent of GH secretion.

C₄₆H₅₆N₁₂O₆ · 873.02 Da

Glucose-dependent Insulinotropic Polypeptide · Gastric Inhibitory Polypeptide

GIP is a 42-amino-acid incretin hormone secreted by duodenal K-cells in response to fat and carbohydrate ingestion. Like GLP-1, it enhances glucose-dependent insulin secretion. Unlike GLP-1, it also promotes insulin secretion during hypoglycemia, protects β-cells, and at high doses may stimulate glucagon in a glucose-independent manner. The GIP receptor's role in energy homeostasis underlies the efficacy of dual GIP/GLP-1 agonists like tirzepatide.

Glucagon-like Peptide-1 · GLP-1(7-37)

GLP-1 is an endogenous incretin hormone secreted by intestinal L-cells in response to nutrient ingestion. It enhances glucose-dependent insulin secretion, suppresses glucagon, slows gastric emptying, and signals satiety to the hypothalamus. Native GLP-1 has a half-life of only 1–2 minutes due to DPP-4 degradation, which drove the development of DPP-4-resistant analogs (semaglutide, liraglutide, exenatide) that are now major drug classes.

GCG

Glucagon is a 29-amino-acid pancreatic alpha-cell hormone and physiological counter-regulator to insulin. It raises blood glucose through hepatic glycogenolysis and gluconeogenesis and is also lipolytic and thermogenic at supraphysiological doses. FDA-approved for hypoglycemia rescue and GI relaxation, it is now a major drug design target as a component of dual (GLP-1/glucagon) and triple agonists for obesity and NASH treatment.

GnRH · Gonadotropin-Releasing Hormone

Gonadorelin is a synthetic decapeptide identical to endogenous GnRH. When administered in pulsatile fashion it stimulates LH and FSH release from the pituitary, driving gonadal testosterone and estrogen production. Clinically used for diagnosing hypothalamic-pituitary dysfunction, treating hypogonadotropic hypogonadism, and inducing ovulation. Paradoxically, continuous administration causes receptor downregulation and hormonal suppression — the basis of GnRH agonist therapy in prostate cancer.

Examorelin · EP 23905

Hexarelin is one of the most potent synthetic GHRP compounds, producing the largest GH pulse among GHRPs. Beyond its GH-stimulating properties, research highlights direct cardioprotective effects through CD36 receptor binding, independent of GH or IGF-1. Studies show benefits in heart failure models, myocardial infarction recovery, and protection against ventricular dysfunction.

HN · mitochondria-derived peptide humanin

Humanin is a 21-amino-acid mitochondria-derived peptide (MDP) encoded within the 16S rRNA gene of mitochondrial DNA. It is cytoprotective against Alzheimer's-related neuronal death, reduces oxidative stress, improves insulin sensitivity, and suppresses apoptosis through multiple pathways (STAT3, IGFBP-3, FPRL1). Circulating humanin levels decline with age, linking it to age-related diseases.

Long R3 IGF-1 · Insulin-like Growth Factor 1 Long R3

IGF-1 LR3 is a modified version of Insulin-like Growth Factor-1 with an arginine substitution and 13-amino-acid N-terminal extension, which reduces binding to IGF-binding proteins and extends its half-life. It promotes muscle cell hyperplasia and hypertrophy by activating the PI3K/AKT/mTOR pathway. Research explores its role in muscle wasting, recovery from injury, and anabolic signaling.

Insulin-like Growth Factor 2 · Somatomedin A

IGF-2 is a 67-amino-acid peptide growth factor closely related to IGF-1, primarily active during fetal and neonatal development. In adults, research highlights its potent cognitive effects — IGF-2 administration after training enhances long-term memory consolidation in rodents by a remarkable degree, acting through IGF2R and mannose-6-phosphate receptors in the hippocampus. It has also emerged as a candidate for treating cognitive deficits in aging and neurodegenerative disease.