Healing & Recovery

AHK-Cu (Ala-His-Lys copper complex, also known as Copper Tripeptide-3) is a synthetic tripeptide–copper chelate structurally related to GHK-Cu (Gly-His-Lys copper complex). It differs from GHK-Cu by a single amino acid substitution at position 1 (Ala instead of Gly), which modifies the copper chelation geometry and may alter tissue distribution and receptor engagement. AHK-Cu is used in cosmetic and hair growth formulations and is an active subject of dermatological research. The only peer-reviewed study directly characterizing AHK-Cu is the 2007 ex vivo/in vitro hair follicle paper (PMID 17703734). No human clinical trials have been conducted. Evidence quality is limited to a single publication at cellular/tissue level.

BPC-157 is a synthetic pentadecapeptide derived from a protective protein found in human gastric juice. It consists of 15 amino acids and is notable for its stability in gastric acid, a property uncommon among peptides of its size. Research interest centers on its cytoprotective effects across multiple organ systems, including the gastrointestinal tract, musculoskeletal tissues, and the central nervous system. Unlike many bioactive peptides, BPC-157 has no known natural counterpart at its specific sequence length. It was originally isolated as a fragment of a larger gastric protein and has been studied primarily by research groups at the University of Zagreb. It remains an investigational compound with no regulatory approval for clinical use.

Bronchogen is a synthetic tetrapeptide Ala-Glu-Asp-Leu (AEDL), developed as a pulmonary/bronchial bioregulator by the Khavinson group at the St. Petersburg Institute of Bioregulation and Gerontology. It is derived from bovine lung tissue and proposed to support bronchial epithelial cell function and mucosal integrity through epigenetic gene regulation. Bronchogen has the thinnest published evidence base among the commercially available Khavinson tetrapeptides: a single in vitro DNA thermostability study (PMID 21240358) measuring physical peptide-DNA interactions without assessing cellular function, tissue response, or therapeutic outcome. No animal or human studies with confirmed PMIDs have been published.

Ovagen is a liver-derived peptide bioregulator developed by the Khavinson group at the St. Petersburg Institute of Bioregulation and Gerontology. It is extracted from bovine liver tissue and proposed to support hepatocyte function, liver structural integrity, and protection against hepatotoxic injury. The pentapeptide form Ile-Glu-Pro-Gly-Pro is the most commonly cited sequence, though alternative shorter sequences appear in some vendor and review sources — the sequence field above reflects the predominant published form.

TB-500 is a synthetic version of thymosin beta-4 (Tβ4), a 43-amino acid peptide naturally present in virtually all human and animal cells. Thymosin beta-4 is the primary intracellular G-actin sequestering peptide, playing a central role in cytoskeletal dynamics, cell motility, and tissue repair. The designation "TB-500" refers specifically to the synthetic research-grade form used in investigational settings. The active fragment Ac-SDKP (N-acetyl-seryl-aspartyl-lysyl-proline) is a four-amino acid peptide released by enzymatic cleavage of thymosin beta-4. This tetrapeptide mediates several of the anti-inflammatory and anti-fibrotic effects attributed to the parent molecule. TB-500 remains an unregulated research compound with no clinical approval, though Tβ4-based formulations have entered clinical trials for dermal and ophthalmic applications.

TB-500 Frag 17-23 (Ac-LKKTETQ) designates residues 17–23 of thymosin beta-4 with an N-terminal acetyl group. It is important to understand this compound in its correct context: **TB-500 Frag 17-23 is not a purposefully designed therapeutic peptide.** It was identified analytically by anti-doping researchers as a fragment present in commercial TB-500 (thymosin beta-4) lyophilized preparations — a manufacturing-related impurity or degradation product, not a designed active pharmaceutical ingredient. Some research peptide vendors sell TB-500 Frag 17-23 as an independent product, but this practice reflects commercial opportunism rather than independent therapeutic evidence. The entirety of published data on this fragment is from a single anti-doping analytical study (PMID 22962027) that characterized its presence in commercial TB-500 vials for the purpose of developing urine/plasma detection methods. Researchers and users seeking the therapeutic effects described for TB-500 should refer to the TB-500 (thymosin beta-4) entry, which covers the full protein with its established wound healing, tissue repair, and cardioprotective evidence.