{
  "_meta": {
    "publisher": "peptide.wiki",
    "licence": "CC BY 4.0",
    "licence_url": "https://creativecommons.org/licenses/by/4.0/",
    "attribution": "Data: peptide.wiki (https://www.peptide.wiki/data), CC BY 4.0",
    "version": "2026.11",
    "updated": "2026-11-10"
  },
  "data": [
    {
      "term": "Agonist",
      "definition": "A molecule that binds a receptor and activates it, mimicking the natural signal. Semaglutide, for example, is a GLP-1 receptor agonist.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Amidation (C-terminal)",
      "definition": "Replacing the carboxyl end of a peptide with an amide group. It removes a negative charge, often improves stability and is common in naturally occurring hormones.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Amino acid",
      "definition": "The building block of peptides and proteins. Twenty standard amino acids are encoded by DNA; research peptides sometimes include unnatural or D-form residues.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Analogue",
      "definition": "A compound built by modifying a natural peptide, for instance by swapping residues or adding a fatty-acid chain, to change stability or receptor behaviour.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Antagonist",
      "definition": "A molecule that binds a receptor without activating it, blocking the natural signal.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Acylation",
      "definition": "Attaching a fatty-acid chain to a peptide. It promotes binding to serum albumin and slows clearance, which is how several long-acting GLP-1 analogues are built.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Batch number",
      "definition": "An identifier linking a vial to one manufacturing run and its analytical records, so a Certificate of Analysis can be matched to the material in hand.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Bioavailability",
      "definition": "The fraction of a substance that reaches the circulation in active form. Peptides generally have low oral bioavailability because digestive enzymes break them down.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Certificate of Analysis (CoA)",
      "definition": "A document reporting the tests run on a batch, typically HPLC purity and mass spectrometry identity. It is only meaningful if it matches your batch reference.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Cyclic peptide",
      "definition": "A peptide whose ends or side chains are joined into a ring, for example through a disulfide bond. Ring closure can improve stability and receptor selectivity.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Disulfide bond",
      "definition": "A covalent link between the sulfur atoms of two cysteine residues. It can close a ring within one peptide or join two chains.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Dual agonist",
      "definition": "A compound designed to activate two receptors at once, such as GIP and GLP-1.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Endogenous",
      "definition": "Produced naturally inside the body, as opposed to a synthetic or administered compound.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Evidence level",
      "definition": "peptide.wiki's one-to-five rating of the published literature for a compound, from approved medicine with phase 3 trials (5) to limited preclinical data (1). See the methodology page.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "GHS-R (ghrelin receptor)",
      "definition": "The receptor that growth hormone secretagogues such as ipamorelin and GHRP-6 act on.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "GLP-1",
      "definition": "Glucagon-like peptide-1, an incretin hormone released from the gut. A family of long-acting analogues targets its receptor.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Half-life",
      "definition": "The time for the concentration of a substance to fall by half. Chemical modifications are often made specifically to lengthen a peptide's half-life.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "HPLC",
      "definition": "High-performance liquid chromatography. It separates the components of a sample, and the purity on a CoA is the share of the main peak in the chromatogram.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Incretin",
      "definition": "A gut hormone, such as GLP-1 or GIP, that influences insulin secretion and appetite signalling.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "In vitro",
      "definition": "Done in a dish or test tube rather than in a living organism. Research peptides on this site are described for in vitro laboratory research only.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Isoelectric point (pI)",
      "definition": "The pH at which a peptide carries no net charge. It affects solubility and how the peptide behaves in chromatography.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Lyophilised",
      "definition": "Freeze-dried. Most research peptides are supplied as a lyophilised powder because the dry form is far more stable than a solution.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Mass spectrometry (MS)",
      "definition": "A technique that measures molecular mass. It confirms a peptide's identity by comparing the observed mass with the theoretical mass.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Melanocortin receptors",
      "definition": "A family of five receptors (MC1R to MC5R) involved in pigmentation, appetite and other processes. MC4R and MC1R are the best known.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Molecular weight",
      "definition": "The mass of one mole of a molecule, in g/mol or daltons. It is needed to convert between mass and molar concentrations.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Monoisotopic mass",
      "definition": "Mass calculated using the most abundant isotope of each element. It matches the main peak in high-resolution mass spectrometry.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "N-terminus / C-terminus",
      "definition": "The two ends of a peptide chain: the free amino end and the free carboxyl end. Modifications there, such as acetylation or amidation, change stability and charge.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Net peptide content",
      "definition": "The proportion of a lyophilised vial that is actual peptide, the rest being counter-ions and water. It is usually lower than HPLC purity.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Off-label",
      "definition": "Use of an approved medicine outside its authorised indication. It is a regulatory term for medicines and says nothing about research compounds.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Peptide",
      "definition": "A short chain of amino acids joined by peptide bonds. By convention, chains longer than roughly 50 residues are called proteins.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Peptide bond",
      "definition": "The amide bond joining the carboxyl group of one amino acid to the amino group of the next.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Preclinical",
      "definition": "Research in cells or animals before any human trials. Most data for newer research peptides sits at this stage.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Purity",
      "definition": "On a CoA, usually the percentage of the main peak by HPLC. It describes related peptide impurities, not water or salt content.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Receptor",
      "definition": "A protein, usually on a cell surface, that a signalling molecule binds to in order to trigger a cellular response.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Reconstitution",
      "definition": "Dissolving a lyophilised powder in a solvent to make a solution. See the stock solution calculator for the concentration arithmetic.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Residue",
      "definition": "A single amino acid unit within a peptide chain.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Secretagogue",
      "definition": "A substance that prompts the secretion of another, such as growth hormone secretagogues that prompt pituitary release.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Sequence",
      "definition": "The ordered list of amino acids in a peptide, written from the N-terminus to the C-terminus using one- or three-letter codes.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Trifluoroacetate (TFA) salt",
      "definition": "A common counter-ion left over from peptide purification. It adds mass to the vial, which is why net peptide content is lower than total weight.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Aggregation",
      "definition": "The clumping together of peptide molecules into insoluble assemblies. It is why native human amylin cannot be used directly, and why analogues such as pramlintide were engineered.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Albumin binding",
      "definition": "Reversible attachment of a modified peptide to serum albumin. Fatty-acid side chains promote it, shielding the peptide from clearance and lengthening its half-life.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Alpha-helix",
      "definition": "A common coiled secondary structure in peptides, stabilised by hydrogen bonds along the backbone. Many receptor-binding peptides adopt a helix when they bind.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Chromatogram",
      "definition": "The trace produced by HPLC, with peaks for each component of a sample. Purity is calculated from the area of the main peak relative to the total.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Counter-ion",
      "definition": "A small ion, such as acetate or trifluoroacetate, that balances the charge on a peptide. It contributes to vial weight but is not peptide.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "D-amino acid",
      "definition": "The mirror-image form of an amino acid. Inserting D-residues into a peptide makes it harder for enzymes to cut, as seen in hexarelin and several other secretagogues.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Desensitisation",
      "definition": "A fading response of a receptor after repeated or continuous activation. Ghrelin-receptor agonists such as hexarelin are a well-documented example.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "DPP-4",
      "definition": "Dipeptidyl peptidase-4, an enzyme that rapidly cleaves native GLP-1 and some other peptides. Resistance to it is a major design goal for GLP-1 analogues.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Endotoxin",
      "definition": "A fragment of bacterial cell wall that can contaminate preparations. Endotoxin testing is a standard quality check for peptides used in cell-based work.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Excipient",
      "definition": "An inactive ingredient in a lyophilised product, such as a bulking agent, that helps the freeze-dried cake form and stay stable.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Gastric emptying",
      "definition": "The rate at which the stomach releases food into the intestine. Slowing it is one of the actions of GLP-1 and amylin receptor agonists.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Ghrelin",
      "definition": "A gut-derived hormone that activates the GHS receptor, driving growth hormone release and appetite signalling.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "GHRH",
      "definition": "Growth-hormone-releasing hormone, a 44-residue hypothalamic peptide that prompts the pituitary to release growth hormone. Sermorelin and CJC-1295 are GHRH analogues.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "GIP",
      "definition": "Glucose-dependent insulinotropic polypeptide, an incretin hormone. Dual agonists such as tirzepatide activate both its receptor and the GLP-1 receptor.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Glucagon",
      "definition": "A pancreatic hormone that raises blood glucose and increases energy expenditure. Triple agonists such as retatrutide add activity at its receptor.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "IGF-1",
      "definition": "Insulin-like growth factor 1, produced mainly by the liver in response to growth hormone. It is the main downstream mediator of GH signalling and a common readout in GH-axis research.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Lipolysis",
      "definition": "The breakdown of stored fat into free fatty acids and glycerol.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "m/z",
      "definition": "Mass-to-charge ratio, the quantity a mass spectrometer actually measures. A multiply charged peptide shows several m/z peaks from which its mass is calculated.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Molar concentration",
      "definition": "Moles of a substance per litre. Converting a mg/mL stock to molar needs the molecular weight; see the stock solution calculator.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Oxyntomodulin",
      "definition": "A natural gut hormone that activates both the GLP-1 and glucagon receptors. Several dual agonists are analogues of it.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Pharmacokinetics",
      "definition": "How a compound is absorbed, distributed, broken down and cleared over time. Half-life is its most quoted parameter.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Receptor selectivity",
      "definition": "How strongly a compound prefers one receptor over related ones. High selectivity makes a cleaner research tool; low selectivity brings broader effects.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Solid-phase peptide synthesis (SPPS)",
      "definition": "The standard way to make research peptides: amino acids are added one at a time to a chain anchored on a resin, then the finished peptide is cleaved off and purified.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Truncation",
      "definition": "Using only part of a natural peptide's sequence. Sermorelin is a truncation of GHRH that keeps full activity in 29 of its 44 residues.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Tripeptide",
      "definition": "A peptide of exactly three amino acids, such as GHK, the core of GHK-Cu.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Glucagon receptor (GCGR)",
      "definition": "The receptor activated by the hormone glucagon. Dual agonists such as survodutide and mazdutide combine GLP-1 receptor activity with glucagon-receptor activity.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Mitochondrial-derived peptide (MDP)",
      "definition": "A short peptide encoded within mitochondrial DNA rather than the nuclear genome. Humanin and MOTS-c are the best-known examples.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "PTH1 receptor",
      "definition": "The receptor activated by parathyroid hormone and by its active fragment teriparatide.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Innate repair receptor",
      "definition": "A receptor complex of the erythropoietin receptor and the common beta receptor, associated with tissue-protective rather than blood-cell signalling. ARA 290 was designed to target it.",
      "url": "https://www.peptide.wiki/glossary"
    },
    {
      "term": "Gonadotropin-releasing hormone (GnRH)",
      "definition": "A ten-amino-acid hypothalamic hormone that signals the pituitary to release LH and FSH. Gonadorelin is its synthetic copy.",
      "url": "https://www.peptide.wiki/glossary"
    }
  ]
}