Research

Peptide half-life — the time required for plasma concentration to decrease by 50% — is a fundamental pharmacokinetic parameter that governs study design, dosing frequency, and biological interpretation in peptide research. This article examines enzymatic degradation mechanisms, structural modifications that extend half-life including PEGylation, acetylation, and DAC technology, delivery route considerations, lyophilization and storage stability, and how researchers account for pharmacokinetic variability in experimental design.

AOD-9604 (Anti-Obesity Drug 9604) is a synthetic peptide fragment corresponding to amino acids 177–191 of human growth hormone, modified with a tyrosine residue. Developed by Metabolic Pharmaceuticals, it was designed to retain the fat-metabolizing properties of growth hormone without its growth-promoting and insulin-desensitizing effects. This article reviews AOD-9604’s mechanism of lipolysis induction, its clinical trial history, cartilage repair research, comparison to full-length hGH, and current regulatory status.

Peptide T is a synthetic octapeptide (ASTTTNYT) derived from the V2 region of the HIV-1 gp120 envelope glycoprotein. Developed by Candace Pert and colleagues at the NIH, it was proposed to block HIV entry into CD4+ cells via CD26 (later CCR5) receptor interaction. Research has also examined Peptide T in AIDS dementia complex and broader neuroprotective contexts. This article reviews its discovery, antiviral and neurological research, the evolution of the underlying receptor science, and its current standing.

Insulin-like growth factor 1 (IGF-1) is a 70-amino acid peptide hormone that mediates many of the anabolic and growth-promoting effects of growth hormone. IGF-1 LR3 is an extended recombinant analog with a prolonged half-life designed for research purposes. Studies have investigated their roles in muscle protein synthesis, satellite cell activation, metabolic regulation, and tissue growth. This article also addresses the important dual nature of IGF-1 in cancer biology, a critical consideration for research interpretation.

Melanotan II (MT-II) is a synthetic analog of alpha-melanocyte-stimulating hormone (α-MSH) that acts as a non-selective melanocortin receptor agonist. Research has investigated its effects on skin pigmentation via MC1R, appetite and metabolic regulation via MC4R, sexual function, and cardiovascular physiology. This article reviews the melanocortin receptor system, key preclinical and clinical findings on MT-II’s biological actions, its distinction from MT-1, and the safety flags that have emerged in research literature.

Delta sleep-inducing peptide (DSIP) is a nonapeptide originally isolated from rabbit cerebral venous blood during slow-wave sleep. Research has examined its effects on sleep architecture, EEG delta wave activity, stress hormone regulation, antioxidant defense, and pain modulation. This overview covers DSIP’s discovery, proposed mechanisms, scope of biological effects beyond sleep, research in opioid withdrawal models, and the significant limitations and controversies within the current evidence base.

Semax is a synthetic heptapeptide analog of adrenocorticotropic hormone fragment ACTH(4-7), developed in Russia and registered as a nootropic and neuroprotective drug. Research has demonstrated its ability to upregulate BDNF and NGF expression, protect neurons from ischemic damage, enhance cognitive performance, and support recovery from stroke. This article reviews its molecular structure, neuroprotective mechanisms, key clinical studies, and ongoing research into its cognitive and ADHD-related applications.

Selank is a synthetic heptapeptide analog of the endogenous immunomodulatory peptide tuftsin, developed at the Institute of Molecular Genetics of the Russian Academy of Sciences. Research has examined its anxiolytic properties in animal models, GABAergic modulation, cognitive enhancement effects, and its clinical use in Russia for anxiety disorders. This article reviews the mechanistic basis of Selank’s action, key experimental findings, and its comparison with classical benzodiazepine anxiolytics.

Thymosin Beta-4 (Tβ4) is a 43-amino acid peptide and primary actin-sequestering molecule in eukaryotic cells. Research has identified its roles in wound healing, cardiac repair, anti-inflammatory signaling, and the promotion of tissue regeneration across multiple organ systems. This article reviews the mechanistic biology of Tβ4, its preclinical evidence base in tendon, muscle, and cardiac models, its relationship to the synthetic analog TB-500, and its current clinical development status.

Epithalon (Ala-Glu-Asp-Gly) is a synthetic tetrapeptide developed by Vladimir Khavinson at the St. Petersburg Institute of Bioregulation and Gerontology. Research has focused on its ability to activate telomerase, elongate telomeres in somatic cells, regulate pineal gland function, and extend lifespan in animal models. This overview examines the scientific evidence behind epithalon’s proposed mechanisms, key preclinical and human studies, and its current status in gerontological research.

Metabolic Research GLP-1 Peptides: Understanding the Science Behind Metabolic Research Published: March 2026 • Educational content for research purposes only

Preclinical Research BPC-157 Research: What Studies Show About Tissue Repair Published: March 2026 • Educational content for research purposes only

Research Overview What Are Bioregulator Peptides? A Complete Research Overview Published: March 2026 • Educational content for research purposes only