Peptide Database

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.

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.

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.

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.

NT · NTS

Neurotensin is a 13-amino-acid neuropeptide found in the brain and GI tract. Centrally, it modulates dopamine circuits, acts as an endogenous antipsychotic-like agent, and is analgesic. Peripherally, it inhibits gastric acid secretion, stimulates pancreatic secretion, and promotes fat absorption. Research explores neurotensin analogs for pain, schizophrenia, Parkinson's disease, and metabolic regulation.

Alpha-Melanocyte-Stimulating Hormone · α-Melanotropin

α-MSH is an endogenous 13-amino-acid peptide derived from POMC (pro-opiomelanocortin). It activates MC1R to stimulate melanin production in skin, MC4R to suppress appetite and regulate energy expenditure, and MC3R/MC1R to exert potent anti-inflammatory effects. It is the parent compound from which many synthetic melanocortin analogs (Melanotan I, II, PT-141, KPV) were derived and remains a cornerstone of melanocortin pharmacology research.