Peptide Glossary
Key terms and definitions used throughout this site, spanning biology, pharmacology, regulatory science, and general research concepts. Terms are listed alphabetically.
43 terms across 4 categories
A
- AgonistPharmacology
- A molecule that binds to a receptor and activates it, producing a biological response. For example, growth hormone secretagogues like ipamorelin act as agonists at the ghrelin receptor.
- Related:ipamorelincjc-1295mk-677
- Amino AcidGeneral
- The building blocks of proteins and peptides. There are 20 standard amino acids, each with a unique side chain that determines its chemical properties. Peptides are chains of amino acids linked by peptide bonds.
- AngiogenesisBiology
- The formation of new blood vessels from pre-existing vessels. Angiogenesis plays a key role in wound healing and tissue repair, and is a mechanism through which some peptides like BPC-157 are thought to act.
- Related:bpc-157
- AntagonistPharmacology
- A molecule that binds to a receptor but does not activate it, instead blocking the receptor from being activated by an agonist. Antagonists are used to reduce or inhibit specific biological pathways.
B
- BDNF (Brain-Derived Neurotrophic Factor)Biology
- A protein that supports the survival, growth, and maintenance of neurons. BDNF plays an important role in learning, memory, and mood regulation. Some cognitive peptides may influence BDNF expression.
- Related:semaxdihexa
- BioavailabilityPharmacology
- The proportion of a drug or compound that enters the bloodstream and is available to exert its effect. Oral bioavailability for most peptides is very low because digestive enzymes break them down before absorption.
C
- CathelicidinBiology
- A family of antimicrobial peptides produced by immune cells that help defend the body against bacterial and viral infections. LL-37 is the only human cathelicidin and is central to innate immune defense.
- Related:ll-37
- Clinical TrialRegulatory
- A research study that tests how a medical intervention works in people. Clinical trials follow a phased structure (Phase I through IV) to evaluate safety and efficacy before regulatory approval.
D
- Double-BlindGeneral
- A study design in which neither the participants nor the researchers know who is receiving the active treatment versus the placebo. This minimizes bias and is considered the gold standard for clinical trials.
E
- EndorphinBiology
- Neuropeptides produced by the central nervous system that reduce pain and promote feelings of well-being. Endorphins are among the most well-known naturally occurring peptides in the human body.
F
- FDA ApprovalRegulatory
- Authorization from the U.S. Food and Drug Administration confirming that a drug or treatment is safe and effective for its intended use in humans. Most peptides discussed on this site have not received FDA approval.
G
- GRAS (Generally Recognized as Safe)Regulatory
- A U.S. FDA designation for substances that are considered safe based on expert consensus or extensive history of use. Most research peptides have not received a GRAS designation.
- Growth FactorBiology
- A protein or steroid hormone that stimulates cell growth, proliferation, or differentiation. Peptides like GHK-Cu and IGF-1 act by mimicking or stimulating endogenous growth factors.
- Related:ghk-cumk-677cjc-1295ipamorelin
H
- Half-LifePharmacology
- The time it takes for the concentration of a substance in the body to decrease by half. A longer half-life generally means less frequent dosing is required. CJC-1295 with DAC, for example, has a significantly longer half-life than standard GHRH.
- Related:cjc-1295
- hTERT (Human Telomerase Reverse Transcriptase)Biology
- The catalytic component of telomerase, the enzyme responsible for maintaining telomere length. Epithalon is studied for its potential to activate hTERT expression, which may slow aspects of cellular aging.
- Related:epithalon
I
- IGF-1 (Insulin-Like Growth Factor 1)Biology
- A hormone structurally similar to insulin that promotes growth and has anabolic effects throughout the body. MK-677 and growth hormone secretagogues stimulate the production of IGF-1 via growth hormone release.
- Related:mk-677cjc-1295ipamorelin
- IND (Investigational New Drug)Regulatory
- An application filed with the FDA that allows a new drug to be tested in human clinical trials in the United States. Obtaining an IND is a prerequisite for conducting clinical research on an unapproved compound.
M
- MitochondriaBiology
- The organelles in cells responsible for producing ATP, the primary cellular energy currency. Mitochondrial dysfunction is implicated in aging and many chronic diseases. SS-31 is specifically designed to protect mitochondrial function.
- Related:ss-31
N
- NeuropeptideBiology
- A peptide that acts as a signaling molecule in the nervous system. Neuropeptides regulate a wide range of functions including mood, appetite, pain, and sleep. Selank and Semax are synthetic neuropeptides.
- Related:semaxselankdihexadsip
- NF-kB (Nuclear Factor kappa B)Biology
- A protein complex that acts as a master regulator of inflammation by controlling the transcription of pro-inflammatory genes. Modulating NF-kB activity is a proposed mechanism for several anti-inflammatory peptides.
- Related:bpc-157kpv
- Nitric OxideBiology
- A gaseous signaling molecule produced in the body that relaxes blood vessels, improves blood flow, and modulates inflammation. BPC-157 is thought to exert some of its healing effects by influencing nitric oxide pathways.
- Related:bpc-157
O
- Off-LabelRegulatory
- The use of a drug for a purpose, patient population, or dosage that has not been specifically approved by a regulatory agency. Physicians can legally prescribe approved drugs off-label, but this is distinct from unregulated research use.
P
- Peer-ReviewedGeneral
- A process in which scientific research is evaluated by independent experts in the same field before publication. Peer review helps ensure the quality, validity, and rigor of published findings.
- Peptide BondBiology
- The chemical bond that links amino acids together in a peptide or protein chain. It is formed by a condensation reaction between the carboxyl group of one amino acid and the amino group of the next.
- Phase I / II / III (Clinical Trials)Regulatory
- The three main phases of clinical drug testing. Phase I tests safety in a small group. Phase II tests efficacy and further evaluates safety in a larger group. Phase III tests efficacy in a large, randomized controlled trial to generate the data needed for regulatory approval.
- PlaceboGeneral
- An inert substance or sham treatment given to a control group in a study. Comparing outcomes between the placebo group and the treatment group allows researchers to isolate the true effect of the intervention.
- Placebo-ControlledRegulatory
- A study design in which some participants receive the active treatment and others receive an inert placebo, allowing researchers to isolate and measure the true effect of the treatment.
- PreclinicalRegulatory
- Research conducted in laboratory settings (in vitro, cell culture) or animal models before human trials begin. Most peptides have only preclinical evidence; this is an important limitation when interpreting research findings.
R
- Randomized Controlled Trial (RCT)Regulatory
- A study in which participants are randomly assigned to receive either the treatment or a control (placebo or standard care). RCTs are considered the gold standard for establishing causal evidence of a treatment's effectiveness.
- ReceptorPharmacology
- A protein molecule on or within a cell that receives chemical signals from outside the cell. Peptides exert their effects by binding to specific receptors, triggering a downstream cascade of biological events.
- ReconstitutionPharmacology
- The process of dissolving a lyophilized (freeze-dried) peptide powder in a liquid, typically bacteriostatic water, to prepare it for injection. Reconstitution is required for most injectable research peptides.
S
- SecretagoguePharmacology
- A compound that stimulates the secretion of another substance. Growth hormone secretagogues (GHS), such as ipamorelin and MK-677, stimulate the pituitary gland to release growth hormone.
- Related:ipamorelincjc-1295mk-677
- SenescenceBiology
- The process by which cells permanently stop dividing and enter a state of irreversible growth arrest. Accumulation of senescent cells is a hallmark of aging and may be influenced by telomere shortening.
- Related:epithalon
- SubcutaneousPharmacology
- Referring to the layer of tissue beneath the skin. Subcutaneous injection (injecting into fat tissue just under the skin) is the most common administration route for research peptides.
T
- TelomeraseBiology
- An enzyme that maintains telomere length by adding DNA sequences to the ends of chromosomes. Telomerase activity is high in stem cells and germ cells but low in most somatic cells, contributing to aging.
- Related:epithalon
- TelomereBiology
- Protective caps at the ends of chromosomes that shorten with each cell division. Telomere shortening is considered a key biomarker of cellular aging. Epithalon is studied for its potential to activate telomerase and slow telomere attrition.
- Related:epithalon
V
- VEGF (Vascular Endothelial Growth Factor)Biology
- A signaling protein that stimulates the formation of new blood vessels (angiogenesis). VEGF is central to wound healing and tissue regeneration, and is a proposed target of BPC-157's healing effects.
- Related:bpc-157
W
- WADA (World Anti-Doping Agency)Regulatory
- An international organization that maintains the Prohibited List of substances banned in competitive sport. Many peptides, including growth hormone secretagogues, are prohibited by WADA, making their use a concern for competitive athletes.
- Related:mk-677cjc-1295ipamorelintb-500bpc-157