Peptide Database

Human Neutrophil Peptides (HNP-1, HNP-2, HNP-3) · α-defensins

Alpha-defensins are cationic antimicrobial peptides secreted by neutrophils (HNP-1 to 4) and Paneth cells (HD-5, HD-6) in the small intestine. They kill bacteria, fungi, and enveloped viruses through membrane disruption and also function as chemokines, recruiting immune cells and bridging innate and adaptive immunity. Paneth cell alpha-defensins (HD-5, HD-6) play a critical role in shaping intestinal microbiome composition.

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.

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.

Lys-Pro-Val · α-MSH C-terminal tripeptide

KPV is a tripeptide derived from the C-terminal sequence of alpha-melanocyte-stimulating hormone (α-MSH). It exhibits potent anti-inflammatory effects by inhibiting NF-κB signaling and proinflammatory cytokine production. Research is particularly focused on its potential for inflammatory bowel disease, colitis, and skin inflammation, with studies showing efficacy even when administered orally or topically.

Cathelicidin · hCAP18/LL-37

LL-37 is the only known human cathelicidin antimicrobial peptide, derived from the C-terminus of hCAP18 protein. It exhibits broad-spectrum antimicrobial activity against bacteria, fungi, and viruses by disrupting microbial membranes. Beyond direct killing, LL-37 modulates inflammation, promotes wound healing, and may have anticancer properties. Research focuses on chronic wound care, infection, and skin disorders like rosacea.

Selanc · TP-7

Selank is a synthetic heptapeptide analog of tuftsin developed by the Russian Institute of Molecular Genetics. Approved in Russia for anxiety and cognitive disorders, it exhibits anxiolytic effects comparable to benzodiazepines without sedation or dependence. Research shows it modulates GABA, serotonin, and dopamine systems, enhances BDNF expression, and improves memory consolidation and learning.

C₃₃H₅₇N₁₁O₉ · 751.87 Da

Thymus Humoral Factor-Gamma 2 · THF-γ2

Thymalin is a peptide complex isolated from bovine thymus gland, approved in Russia for use as an immunomodulator. Research demonstrates it restores age-related decline in T-cell function, enhances bone marrow activity, and supports immune homeostasis. Long-term studies in elderly populations show reductions in all-cause mortality and improved immune resilience, positioning it as a key anti-aging immunotherapy research compound.

TP-5 · Timunox

Thymopentin (TP-5) is a synthetic pentapeptide corresponding to positions 32–36 of thymopoietin. It is approved in several countries for HIV infection, rheumatoid arthritis, and immune deficiencies. Research shows it selectively promotes T-cell maturation and differentiation, enhancing both cellular and humoral immune responses without causing immunosuppression.

Thymalfasin · Tα1

Thymosin Alpha-1 is a naturally occurring 28-amino-acid peptide derived from thymosin fraction 5 of the thymus gland. Approved in over 35 countries for hepatitis B, hepatitis C, and as an immune adjuvant in cancer therapy, it enhances T-cell maturation, dendritic cell function, and NK cell activity. Research continues to expand into sepsis, COVID-19, autoimmune conditions, and vaccine response enhancement.

C₁₂₉H₂₁₅N₃₃O₅₅ · 3108.29 Da

Tβ4 · LKKTETQ

Thymosin Beta-4 is the full-length 43-amino-acid peptide and one of the most abundant intracellular proteins in mammalian cells. It sequesters G-actin, regulating actin polymerization and cell motility, which underpins its role in wound healing, cardiac repair, and immune cell migration. Clinical trials have examined it for dry eye disease, epidermolysis bullosa, and cardiac repair after myocardial infarction.

Serum Thymic Factor · Facteur Thymique Sérique

Thymulin is a nonapeptide produced exclusively by thymic epithelial cells, requiring zinc for biological activity. It promotes T-cell differentiation, enhances cytokine production, and is a key marker of thymic function. Circulating thymulin levels decline with age, paralleling thymic involution. Research examines its role in autoimmunity, inflammatory diseases, and as a zinc-dependent immune regulator in aging.

Lys-Glu · KE dipeptide

Vilon is a synthetic dipeptide (Lys-Glu) developed at the St. Petersburg Institute of Bioregulation and Gerontology as a vascular cytoprotective peptide. Research demonstrates it reduces vascular endothelial cell aging, suppresses excessive collagen synthesis, and modulates the renin-angiotensin system. Long-term animal studies show improved vascular function and survival; it is often studied as part of peptide longevity protocols.

Vasoactive Intestinal Peptide · Vasoactive Intestinal Polypeptide

VIP (Vasoactive Intestinal Peptide) is a 28-amino-acid neuropeptide with pleiotropic anti-inflammatory, bronchodilatory, and immunomodulatory effects mediated through VPAC1 and VPAC2 receptors. Research spans pulmonary arterial hypertension (inhaled VIP trials), inflammatory bowel disease, sepsis, Parkinson's disease, and CIRS (chronic inflammatory response syndrome). It suppresses Th1 cytokines and promotes Treg cell function.