Peptide Families

The peptide drug class that has reshaped diabetes and obesity care over 2005-2026 — GLP-1 receptor agonists plus the dual GLP-1/GIP and triple GLP-1/GIP/glucagon multi-receptor agonists. Founded by exenatide (a venom-derived peptide approved 2005) and now anchored by semaglutide, tirzepatide, and retatrutide, with cardiovascular, kidney, and MASH outcomes data.

A family of small copper-binding tripeptides — GHK-Cu, AHK-Cu, and palmitoyl variants — that form stable copper(II) complexes with documented effects on collagen synthesis, wound healing, and skin remodeling. Founded by Loren Pickart's 1973 isolation of GHK-Cu and now a fixture of cosmetic dermatology and the wound-care literature.

The peptide family of α-MSH analogs and selective melanocortin-receptor agonists — covering pigmentation (afamelanotide, melanotan-II), monogenic obesity (setmelanotide), and female sexual desire (bremelanotide / PT-141), plus the immunomodulatory KPV tripeptide and the cosmetic α-MSH analog nonapeptide-1.

The peptide family that stimulates pulsatile endogenous growth hormone release rather than supplying exogenous GH directly. Two mechanistic branches: GHRH analogs (sermorelin, CJC-1295, tesamorelin) acting at the GHRH receptor, and ghrelin receptor agonists (GHRP-2, GHRP-6, hexarelin, ipamorelin, MK-677/ibutamoren) acting at GHSR1a. Often stacked together for synergistic GH pulses.

The peptide family of synthetic amylin agonists — pramlintide (FDA-approved 2005 for diabetes adjunct), cagrilintide (long-acting weekly amylin in CagriSema combination with semaglutide), petrelintide and eloralintide (next-generation Phase 2/3 amylin analogs), plus the multi-receptor amycretin (amylin+GLP-1). Amylin co-administered with GLP-1 has emerged as the dominant combination strategy for next-generation obesity pharmacotherapy.

The cosmetic peptide actives applied topically for skin aging, wrinkles, and pigmentation — including argireline (acetyl hexapeptide-8, the SNAP-25-targeting 'topical Botox' analog), matrixyl (palmitoyl pentapeptide-4, the matrikine collagen stimulator), syn-ake (the snake-venom-derived nicotinic-receptor antagonist), SNAP-8, vialox, rigin, and the broader cluster of palmitoylated tripeptides, palmitoylated tetrapeptides, and signal peptides used in cosmetic formulations.

Two distinct meanings of 'collagen peptide' that consumer marketing often conflates: (1) oral hydrolyzed-collagen protein supplements (gelatin-derived powders sold for skin, hair, and joint health) with modest RCT support for skin elasticity and moisture, and (2) cosmetic 'matrikine' peptides (Matrixyl, syn-coll, palmitoyl-tripeptide-1, GHK-Cu) that stimulate fibroblast collagen synthesis topically. Different molecules, different routes, different evidence bases.

The peptide family derived from thymic tissue and its synthetic analogs — Thymosin α-1 (Zadaxin / thymalfasin, immune modulation), Thymosin β-4 (TB-500, tissue repair through actin sequestration), Thymalin (Russian-tradition thymic-extract preparation), Thymulin (zinc-dependent thymic hormone), and Thymagen (Khavinson-program synthetic thymic peptide). Two functional branches: α-family for immune function, β-family for actin-mediated tissue repair.

The peptide family anchored by somatostatin (SRIF, isolated by Brazeau and Vale at the Salk Institute in 1973) and its long-acting synthetic analogs — octreotide (Sandostatin), lanreotide (Somatuline), pasireotide (Signifor) — used clinically for acromegaly, neuroendocrine tumors, Cushing's disease, and post-operative pancreatic fistula prophylaxis. The endogenous family also includes cortistatin, the somatostatin paralog with overlapping but distinct pharmacology.

The peptide family of synthetic gonadotropin-releasing hormone (GnRH) agonists and antagonists — leuprolide, triptorelin, goserelin, buserelin, nafarelin, histrelin (agonists) and degarelix (antagonist) — used clinically for prostate cancer, endometriosis, central precocious puberty, and IVF cycle regulation. Plus the upstream master regulator kisspeptin and the diagnostic prototype gonadorelin.

The cardiac and vascular peptide family centered on atrial natriuretic peptide (ANP, de Bold 1981), B-type natriuretic peptide (BNP, Sudoh 1988), and C-type natriuretic peptide (CNP, Sudoh 1990) — the endogenous regulators of vascular tone, sodium balance, and fluid homeostasis. Plus nesiritide (recombinant BNP, FDA-approved 2001 for acute heart failure) and the related vascular peptide adrenomedullin.

The endogenous peptide ligands of the mu, delta, and kappa opioid receptors — the enkephalins (Hughes & Kosterlitz 1975), beta-endorphin, dynorphin (Goldstein 1979), endomorphin-1 and -2, nociceptin/orphanin FQ, plus food-derived exorphins (casomorphin) and the indirect opioid analgesic kyotorphin. The neurobiological basis of endogenous pain modulation, reward, and stress response.

The peptide family of host-defense antimicrobial peptides — LL-37 (the human cathelicidin), KPV (the alpha-MSH-derived anti-inflammatory tripeptide), lactoferricin (the lactoferrin-derived antimicrobial), DS-5, plus the broader research-tier cluster including tuftsin, hepcidin, and larazotide. Antimicrobial peptides are an active drug-development area for resistant infections, mucosal immunity, and inflammatory disease, with origins traceable to Michael Zasloff's 1987 discovery of the magainins.

A catalog of synthetic short peptides (typically 2-4 amino acids) developed at the St. Petersburg Institute of Bioregulation and Gerontology since the 1970s, positioned as tissue-specific epigenetic regulators of gene expression. The catalog spans 20+ entries — Epitalon, Cortagen, Pinealon, Vilon, Thymalin, Cardiogen, Bronchogen, and others — each targeted at a specific organ. A real Russian peer-reviewed literature with substantial preclinical depth, but a mechanistically speculative framework that has not been validated to mainstream Western molecular-biology standards.