Peptide Science Glossary

The fundamental building blocks of proteins and peptides. There are 20 standard amino acids, each with a unique side chain that determines its chemical properties. Amino acids are linked together by peptide bonds to form polypeptide chains. The sequence of amino acids in a peptide determines its three-dimensional structure and biological function.

The physiological process by which new blood vessels form from pre-existing vessels. Angiogenesis is a critical component of wound healing and tissue repair, as new blood vessels deliver oxygen and nutrients to healing tissue. Many peptides, including BPC-157 and TB-500, promote angiogenesis through mechanisms involving VEGF upregulation and endothelial cell activation.

The proportion of a substance that enters the circulation when introduced into the body and is thus available to have an active effect. For peptides, bioavailability varies significantly depending on the route of administration. Oral bioavailability of most peptides is low due to degradation by digestive enzymes, which is why many research peptides are administered subcutaneously or intramuscularly.

Body Protection Compound-157, a synthetic pentadecapeptide (15 amino acids) derived from a protective protein found in human gastric juice. BPC-157 has demonstrated remarkable tissue-healing properties in preclinical research, including effects on tendon, ligament, muscle, and gastrointestinal tissue. Its mechanisms include VEGF upregulation, nitric oxide modulation, and FAK-paxillin pathway activation.

A synthetic analog of growth hormone-releasing hormone (GHRH) with modifications that extend its half-life. CJC-1295 with DAC (Drug Affinity Complex) binds to albumin in the bloodstream, extending its half-life from minutes to days. It stimulates the pituitary gland to release growth hormone in a pulsatile, physiologically appropriate manner.

The most abundant protein in the human body, forming the structural framework of skin, bones, tendons, ligaments, and other connective tissues. Collagen is composed of three polypeptide chains wound into a triple helix. Its production declines with age, contributing to skin aging, reduced joint flexibility, and impaired wound healing. Several peptides, including GHK-Cu, stimulate collagen synthesis.

A peptide consisting of exactly two amino acid residues joined by a single peptide bond. Dipeptides are the simplest form of peptide and can have significant biological activity. For example, carnosine (beta-alanyl-L-histidine) is a naturally occurring dipeptide with antioxidant and anti-aging properties.

The study of heritable changes in gene expression that do not involve changes to the underlying DNA sequence. Epigenetic modifications include DNA methylation, histone modification, and non-coding RNA regulation. Several longevity peptides, including Epitalon, are thought to exert their effects partly through epigenetic mechanisms, potentially resetting age-related epigenetic changes.

A synthetic tetrapeptide (Ala-Glu-Asp-Gly) developed by the St. Petersburg Institute of Bioregulation and Gerontology. Epitalon is one of the most studied longevity peptides, with proposed mechanisms including telomerase activation, melatonin regulation, and antioxidant effects. It is based on the naturally occurring pineal peptide Epithalamin.

Glycyl-L-histidyl-L-lysine copper complex, a naturally occurring tripeptide-copper complex found in human plasma, saliva, and urine. GHK-Cu has demonstrated multiple biological activities including stimulation of collagen and elastin synthesis, wound healing acceleration, antioxidant effects, and anti-inflammatory activity. It is widely studied in the context of skin aging and aesthetic medicine.

Growth Hormone-Releasing Hormone, a 44-amino-acid peptide produced by the hypothalamus that stimulates the pituitary gland to synthesize and secrete growth hormone. GHRH analogs such as Sermorelin and CJC-1295 mimic the action of endogenous GHRH and are used in research to study growth hormone secretion and its physiological effects.

Growth Hormone-Releasing Peptides, a class of synthetic peptides that stimulate growth hormone release through the ghrelin receptor pathway. GHRPs include GHRP-2, GHRP-6, Ipamorelin, and Hexarelin. They work synergistically with GHRH analogs, making them commonly studied in combination protocols.

The time required for the concentration of a substance in the body to decrease by half. Peptide half-lives vary enormously — from minutes for unmodified peptides to days for albumin-binding analogs like CJC-1295 DAC. Understanding half-life is essential for designing appropriate research dosing protocols and interpreting pharmacokinetic data.

A peptide consisting of six amino acid residues. Several important research peptides are hexapeptides, including GHRP-6 (a growth hormone secretagogue) and certain cosmetic peptides used in aesthetic research. The term describes the peptide's length and does not imply any specific biological activity.

Insulin-Like Growth Factor 1, a peptide hormone produced primarily by the liver in response to growth hormone stimulation. IGF-1 mediates many of the anabolic effects of growth hormone, including muscle protein synthesis, bone growth, and cellular proliferation. Several research peptides, including Mechano Growth Factor (MGF), are derived from the IGF-1 gene.

A synthetic pentapeptide and selective growth hormone secretagogue that stimulates GH release through the ghrelin receptor. Ipamorelin is notable for its high selectivity — it stimulates GH release with minimal effects on cortisol, prolactin, or appetite, making it one of the most studied GHRPs for research applications requiring isolated GH stimulation.

Also known as freeze-drying, lyophilization is a process that removes water from a product by freezing it and then reducing the surrounding pressure to allow the frozen water to sublimate directly from solid to gas. Most research peptides are supplied in lyophilized form, which dramatically extends their shelf life by preventing hydrolysis and other water-dependent degradation reactions.

The specific biochemical interaction through which a drug or compound produces its pharmacological effect. For peptides, mechanisms of action typically involve binding to specific receptors, enzymes, or other proteins, triggering downstream signaling cascades. Understanding a peptide's mechanism of action is essential for predicting its effects, potential interactions, and appropriate research applications.

A synthetic analog of alpha-melanocyte-stimulating hormone (α-MSH) that binds to melanocortin receptors. Melanotan II has been studied for its effects on skin pigmentation, sexual function, and appetite regulation. It is a non-selective melanocortin receptor agonist, binding to MC1R, MC3R, MC4R, and MC5R.

A peptide that functions as a neurotransmitter or neuromodulator in the nervous system. Neuropeptides are released by neurons and can influence the activity of other neurons, endocrine cells, and immune cells. Examples include substance P, neuropeptide Y, and vasoactive intestinal peptide. Some research peptides, including Semax and Selank, are designed to interact with neuropeptide systems.

A peptide consisting of a relatively small number of amino acids, typically between 2 and 20. Most research peptides are oligopeptides. The term distinguishes these shorter chains from polypeptides (typically 20-50 amino acids) and proteins (generally more than 50 amino acids).

The covalent chemical bond formed between the carboxyl group of one amino acid and the amino group of another, with the release of a water molecule. Peptide bonds are the fundamental structural links in peptides and proteins. They are relatively stable under physiological conditions but can be cleaved by proteolytic enzymes (proteases) or by acid/base hydrolysis.

A peptide consisting of exactly 15 amino acid residues. BPC-157 is the most well-known pentadecapeptide in research contexts. The prefix 'penta' means five and 'deca' means ten, together indicating fifteen amino acids.

A molecule that binds to a receptor and activates it, producing a biological response. Most peptide hormones function as receptor agonists, binding to specific receptors and triggering downstream signaling cascades. Synthetic peptide analogs are often designed to be more potent or selective agonists than the natural peptide they mimic.

The process of dissolving a lyophilized (freeze-dried) peptide in an appropriate solvent to prepare it for use. Common reconstitution solvents include sterile water, bacteriostatic water, and dilute acetic acid solutions. The choice of solvent depends on the peptide's solubility characteristics, and proper reconstitution technique is essential for maintaining peptide integrity.

A substance that causes another substance to be secreted. Growth hormone secretagogues (GHS) are compounds that stimulate the pituitary gland to secrete growth hormone. This class includes both GHRH analogs (which act through GHRH receptors) and ghrelin mimetics (which act through the ghrelin receptor/GHS-R).

A synthetic analog of growth hormone-releasing hormone consisting of the first 29 amino acids of GHRH. Sermorelin is the shortest GHRH fragment with full biological activity and has the longest clinical research history of any GHRH analog. It has been used diagnostically to assess growth hormone secretory capacity.

A synthetic peptide corresponding to the actin-binding domain of Thymosin Beta-4 (amino acids 17-23). TB-500 promotes tissue repair through multiple mechanisms including angiogenesis, anti-inflammatory signaling, and modulation of actin dynamics. It is frequently studied in combination with BPC-157 for synergistic tissue repair effects.

Repetitive DNA sequences (TTAGGG in humans) that cap the ends of chromosomes, protecting them from degradation and preventing chromosomal fusion. Telomeres shorten with each cell division, and critically short telomeres trigger cellular senescence or apoptosis. Telomere length is considered a biomarker of biological aging, and telomerase activation is a key mechanism proposed for longevity peptides like Epitalon.

A peptide consisting of exactly four amino acid residues. Epitalon (Ala-Glu-Asp-Gly) is the most well-known tetrapeptide in longevity research. Several cosmetic peptides, including PKEK (Pro-Lys-Glu-Lys), are also tetrapeptides.

Vascular Endothelial Growth Factor, a signal protein that stimulates the formation of new blood vessels (angiogenesis) and increases vascular permeability. VEGF upregulation is one of the primary mechanisms by which BPC-157 promotes tissue healing. VEGF binds to receptors on endothelial cells, triggering their proliferation, migration, and organization into new capillary networks.