Peptide Database
265 therapeutic peptides with research summaries, clinical findings, and regulatory status.
Thymalin
A peptide bioregulator originally extracted from bovine thymus gland, consisting of a mixture of polypeptides that modulate immune function. Thymalin restores T-cell mediated immunity by promoting T-lymphocyte maturation and differentiation in the thymus. It also normalizes the ratio of T-helper to T-suppressor cells and enhances phagocytic activity of neutrophils and macrophages.
LL-37
The only human cathelicidin antimicrobial peptide, a 37-amino acid cationic peptide cleaved from the precursor protein hCAP18. LL-37 disrupts microbial membranes through electrostatic interactions and exerts broad-spectrum activity against bacteria, fungi, and enveloped viruses. Beyond direct antimicrobial effects, it modulates innate immunity by recruiting immune cells, promoting angiogenesis, and regulating inflammatory cytokine release.
VIP (Vasoactive Intestinal Peptide)
A 28-amino acid neuropeptide widely distributed in the central and peripheral nervous systems and immune cells. VIP acts through VPAC1 and VPAC2 receptors to produce potent anti-inflammatory effects by inhibiting the production of pro-inflammatory cytokines (TNF-alpha, IL-6, IL-12) and promoting regulatory T-cell differentiation. It also functions as a vasodilator, bronchodilator, and neuromodulator.
Thymosin Alpha 1 (Zadaxin)
A 28-amino acid peptide originally isolated from thymic tissue (thymosin fraction 5) that serves as a potent immunomodulator. Thymosin alpha 1 enhances T-cell maturation, dendritic cell function, and antibody responses by activating Toll-like receptors (TLR2, TLR9) on innate immune cells. It promotes Th1 immune responses and augments vaccine efficacy while modulating inflammatory cytokine production.
Thymopentin (TP-5)
A synthetic pentapeptide (Arg-Lys-Asp-Val-Tyr) corresponding to residues 32-36 of thymopoietin, a thymic hormone involved in T-cell differentiation. Thymopentin stimulates early T-cell precursor differentiation and modulates mature T-cell function by enhancing IL-2 production and expression of T-cell surface markers. It partially restores immune function in immunocompromised states without the risks of whole thymic extracts.
Thymulin
A zinc-containing nonapeptide (facteur thymique serique) produced exclusively by thymic epithelial cells. Thymulin requires zinc for biological activity and promotes T-lymphocyte differentiation, maturation, and function. Circulating thymulin levels decline progressively with age in parallel with thymic involution, and zinc deficiency independently impairs thymulin activity, linking nutritional status to immune competence.
KPV
A C-terminal tripeptide fragment (Lys-Pro-Val) of alpha-melanocyte-stimulating hormone (alpha-MSH) that retains potent anti-inflammatory activity without melanogenic effects. KPV inhibits NF-kB nuclear translocation and reduces production of pro-inflammatory cytokines including TNF-alpha, IL-1beta, and IL-6. It penetrates cell membranes and directly interacts with inflammatory signaling cascades, making it effective topically and orally for mucosal inflammation.
Icatibant (Firazyr)
A synthetic decapeptide bradykinin B2 receptor antagonist containing five non-natural amino acids for enhanced stability and receptor selectivity. Icatibant competitively blocks bradykinin, the primary mediator of swelling in hereditary angioedema (HAE) caused by C1 esterase inhibitor deficiency. By preventing bradykinin-induced vasodilation and increased vascular permeability, it rapidly reverses mucosal and subcutaneous edema.
Thymogen (Glutamyl-Tryptophan)
Thymogen is a dipeptide consisting of glutamic acid and tryptophan, originally isolated from thymic extracts and proposed to function as an immunomodulatory agent. It is thought to influence T-cell differentiation and cytokine production, thereby enhancing cellular immunity in states of immune suppression or aging-related immunosenescence. The peptide has been investigated primarily in Eastern European and Russian research settings for adjunctive therapy in infections and immune deficiencies.
Thymostimulin (TP-1)
Thymostimulin is a polypeptide extract derived from bovine thymus tissue containing multiple biologically active thymic peptides. It acts on T-lymphocyte maturation and differentiation by mimicking thymic hormone activity. The therapeutic rationale centers on restoring or augmenting immune function in states of T-cell deficiency or immunosuppression.
Splenopentin
Splenopentin is a synthetic pentapeptide (Arg-Lys-Glu-Val-Tyr) corresponding to residues 32 to 36 of the splenic hormone splenin. It modulates immune cell function by enhancing macrophage activity and stimulating antibody production. The therapeutic rationale is to provide targeted immune enhancement without whole-organ extract variability.
Bursin
Bursin is a tripeptide (Lys-His-Gly) originally isolated from the bursa of Fabricius in avian species. It promotes B-lymphocyte differentiation and immunoglobulin production. The therapeutic rationale is to selectively enhance humoral immunity in conditions marked by antibody deficiency.
Tuftsin
Tuftsin is a naturally occurring tetrapeptide (Thr-Lys-Pro-Arg) cleaved from the Fc portion of the heavy chain of immunoglobulin G. It binds to specific receptors on phagocytes, enhancing chemotaxis, phagocytosis, and microbicidal activity. The therapeutic rationale is to augment innate immune responses in immunocompromised states or chronic infections.
Imuthiol (Diethyldithiocarbamate)
Imuthiol is the sodium salt of diethyldithiocarbamate, a small molecule rather than a peptide, historically explored for immune modulation and antiviral properties. It is thought to alter cytokine profiles and scavenge reactive oxygen species. Therapeutic interest has focused on HIV infection and other states of immune dysregulation.
Alpha-MSH
Alpha-melanocyte-stimulating hormone (alpha-MSH) is a 13-amino-acid peptide derived from proopiomelanocortin (POMC). It acts via melanocortin receptors to exert potent anti-inflammatory and immunomodulatory effects, including suppression of proinflammatory cytokines and inhibition of nuclear factor kappa B (NF-kB). Therapeutic interest spans inflammatory and autoimmune disorders.
Beta-Defensin 2
Beta-defensin 2 (hBD-2) is an antimicrobial peptide of approximately 40 amino acids produced by epithelial cells in response to infection or inflammation. It disrupts microbial membranes and also functions as a chemoattractant for immune cells via CCR6 receptor binding. Therapeutic interest includes infection control and immune adjuvant applications.
Beta-Defensin 3
Beta-defensin 3 (hBD-3) is an antimicrobial peptide of approximately 45 amino acids with potent activity against a wide range of pathogens, including antibiotic-resistant strains. It acts by permeabilizing microbial membranes and modulating host immune responses. Therapeutic applications include topical antimicrobial therapy and vaccine adjuvants.
Granulysin
Granulysin is a 15-kDa antimicrobial and cytolytic protein expressed by cytotoxic T lymphocytes and natural killer cells. It disrupts microbial and tumor cell membranes via lipid interactions and induces apoptosis. The therapeutic rationale includes treatment of intracellular infections and cancer immunotherapy.