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    Reference

    Glossary

    Searchable reference of 77 research compound and peptide terms.

    A

    Acetylation
    A chemical modification where an acetyl group is added to a molecule, often to improve stability or bioavailability of peptides.
    Adjuvant
    A substance that enhances the body's immune response, sometimes used in research compound formulations.
    Agonist
    A compound that binds to a receptor and activates it, producing a biological response. Opposite of antagonist.
    Amino acid
    The building blocks of peptides and proteins. There are 20 standard amino acids that combine in various sequences to form peptides.
    Amidation
    A modification at the C-terminus of a peptide that replaces the carboxyl group with an amide group, often improving receptor binding and stability.
    Anabolic
    Relating to the building up of complex molecules in the body, such as muscle tissue. Opposite of catabolic.
    Antagonist
    A compound that binds to a receptor and blocks its activation, preventing the natural ligand from producing its effect.
    Autophagy
    A cellular recycling process where damaged components are broken down and reused. Several research compounds aim to upregulate this process.

    B

    BAC water
    Bacteriostatic water — sterile water containing 0.9% benzyl alcohol as a preservative. Used to reconstitute lyophilized peptides. Allows multi-use over ~28 days.
    Bioavailability
    The proportion of a compound that enters systemic circulation and is available for biological activity. Varies by administration route.
    Biomarker
    A measurable indicator of a biological state or condition, such as blood glucose, IGF-1, or inflammatory markers like CRP.
    BPC-157 →
    Body Protection Compound-157. A pentadecapeptide (15 amino acids) derived from human gastric juice, researched for its healing and tissue-repair properties.

    C

    Carrier protein
    A protein that binds to and transports another molecule through the bloodstream. Relevant to understanding compound half-life and clearance.
    Catabolic
    Relating to the breakdown of complex molecules into simpler ones, often releasing energy. Opposite of anabolic.
    Certificate of Analysis (COA) →
    A document from a third-party laboratory verifying the identity, purity, and potency of a research compound. A key indicator of vendor quality.
    CJC-1295 →
    A synthetic analog of growth hormone-releasing hormone (GHRH) with a longer half-life. Often used with Ipamorelin as a GH secretagogue stack.
    Clearance
    The rate at which a compound is removed from the body, typically measured in volume per unit time (e.g., mL/min).
    COA grade
    A rating assigned to a vendor's Certificate of Analysis based on lab accreditation, purity results, test date recency, and verification status.
    Concentration
    The amount of active compound per unit volume after reconstitution, typically expressed as mcg/mL or mg/mL.
    Cycle
    A defined period of compound use followed by a break. Cycling helps prevent receptor desensitization and allows the body to recover.
    Cytokine
    Small signaling proteins released by cells that regulate immune responses, inflammation, and cellular communication.

    D

    Desensitization
    Reduced receptor response after prolonged or repeated exposure to a compound. A key reason for cycling protocols.
    Dihexa →
    A nootropic hexapeptide analog of angiotensin IV, researched for cognitive enhancement and neuroprotective effects. Oral dosing typically 10–20 mg.
    Dose-response curve
    A graph showing the relationship between compound dose and the magnitude of biological effect. Used to identify minimum effective and maximum tolerated doses.

    E

    Endogenous
    Produced naturally within the body. Opposite of exogenous. Example: endogenous growth hormone vs. exogenous GH peptides.
    Epithalon →
    A tetrapeptide (Ala-Glu-Asp-Gly) that activates telomerase, researched for anti-aging and telomere length maintenance.
    Exogenous
    Introduced from outside the body. Research compounds are exogenous substances that mimic or modulate endogenous processes.

    G

    GH secretagogue
    A compound that stimulates the release of growth hormone from the pituitary gland. Includes GHRH analogs and ghrelin mimetics.
    GHRH
    Growth Hormone-Releasing Hormone. A natural hormone that stimulates GH release. CJC-1295 is a synthetic GHRH analog.
    GHK-Cu →
    A copper-binding tripeptide (Gly-His-Lys-Cu) researched for skin regeneration, wound healing, collagen synthesis, and hair growth.
    GLP-1
    Glucagon-Like Peptide-1. An incretin hormone that regulates blood sugar and appetite. Semaglutide and tirzepatide are GLP-1 receptor agonists.

    H

    Half-life →
    The time required for the concentration of a compound in the body to decrease by 50%. Determines dosing frequency.
    HPLC
    High-Performance Liquid Chromatography. An analytical technique used in COA testing to measure peptide purity, typically reported as a percentage.
    Hypothalamic-pituitary axis
    The hormonal feedback system connecting the hypothalamus and pituitary gland. Many research compounds interact with this axis.

    I

    IGF-1
    Insulin-like Growth Factor 1. A hormone produced in response to growth hormone, mediating many of GH's effects on tissue growth and repair.
    IM injection
    Intramuscular injection. Compound is injected directly into muscle tissue, typically providing slower absorption than subcutaneous injection.
    Insulin syringe
    A syringe calibrated in units (typically 100 units = 1 mL) used for precise subcutaneous injections of reconstituted peptides.
    Intranasal
    Administration through the nasal mucosa. Used for compounds like Selank and Semax that can cross the blood-brain barrier via this route.
    Ipamorelin →
    A selective growth hormone secretagogue that stimulates GH release with minimal effect on cortisol or prolactin. Often stacked with CJC-1295.
    IV injection
    Intravenous injection. Compound is delivered directly into a vein for immediate systemic availability. Rarely used outside clinical settings.

    K

    KPV
    A tripeptide (Lys-Pro-Val) derived from alpha-MSH, researched for its anti-inflammatory properties, particularly in gut and skin conditions.

    L

    Loading dose
    A higher initial dose used at the start of a protocol to rapidly achieve effective tissue concentrations before switching to a maintenance dose.
    Lyophilized
    Freeze-dried. Peptides are commonly sold in lyophilized (powder) form for stability and must be reconstituted with BAC water before use.

    M

    Mass spectrometry
    An analytical technique that measures molecular weight and structure. Used in COA testing to confirm peptide identity.
    mcg
    Microgram. One millionth of a gram (1/1000 of a milligram). The standard unit for peptide dosing.
    Mechanism of action (MOA)
    The specific biochemical process through which a compound produces its effect, such as receptor binding, enzyme inhibition, or gene expression modulation.
    Melanotan II →
    A synthetic analog of alpha-melanocyte-stimulating hormone (α-MSH), researched for tanning, libido, and appetite effects.
    mTOR
    Mechanistic Target of Rapamycin. A key cellular signaling pathway that regulates growth, protein synthesis, and autophagy.

    N

    Neuropeptide
    A peptide that acts as a neurotransmitter or neuromodulator in the nervous system. Examples include Selank, Semax, and Dihexa.
    Nootropic
    A compound that enhances cognitive function — memory, focus, learning, or neuroprotection — without significant side effects.

    O

    Oral bioavailability
    The fraction of an orally administered compound that reaches systemic circulation. Many peptides have low oral bioavailability due to GI degradation.

    P

    Peptide
    A short chain of amino acids (typically 2–50) linked by peptide bonds. Smaller than proteins, peptides are the basis of most research compounds discussed on this platform.
    Peptide bond
    The covalent chemical bond formed between the carboxyl group of one amino acid and the amino group of another during protein synthesis.
    Pharmacokinetics
    The study of how the body absorbs, distributes, metabolizes, and excretes a compound (ADME). Determines dosing schedules.
    Pituitary gland
    A small gland at the base of the brain that produces hormones including growth hormone, LH, FSH, and ACTH. Target of many GH secretagogues.
    Preclinical
    Research stage before human trials. Includes in vitro (cell) and in vivo (animal) studies. Many research compounds are at this stage.
    PT-141 →
    Bremelanotide. A melanocortin receptor agonist researched for sexual dysfunction. FDA-approved (Vyleesi) for hypoactive sexual desire disorder in women.
    Purity
    The percentage of a sample that consists of the intended compound, as measured by HPLC or mass spectrometry. High-quality vendors achieve ≥98% purity.

    R

    Receptor
    A protein on or in a cell that binds to a specific molecule (ligand), triggering a biological response. Compounds work by activating or blocking receptors.
    Reconstitution →
    The process of dissolving a lyophilized (freeze-dried) peptide in bacteriostatic water to create an injectable solution.
    Retatrutide
    A triple-agonist peptide targeting GLP-1, GIP, and glucagon receptors simultaneously. Researched for obesity and metabolic conditions.

    S

    Selank →
    A synthetic analog of the immunomodulatory peptide tuftsin, researched for anxiolytic and nootropic effects. Administered intranasally.
    Semaglutide →
    A GLP-1 receptor agonist used for weight management and blood sugar control. Available in injectable and oral forms. FDA-approved as Ozempic/Wegovy.
    Semax →
    A synthetic analog of ACTH(4-10) researched for cognitive enhancement, neuroprotection, and improved focus. Administered intranasally.
    Stacking
    Using two or more compounds simultaneously in a protocol, often to achieve synergistic effects. Example: BPC-157 + TB-500 for healing.
    SubQ injection
    Subcutaneous injection. Compound is injected into the fat layer beneath the skin, typically in the abdomen. The most common administration route for peptides.
    Syringe units
    Measurement markings on an insulin syringe. 100 units = 1 mL. Used to measure precise peptide doses after reconstitution.

    T

    TB-500 →
    Thymosin Beta-4. A 43-amino-acid peptide involved in tissue repair, cell migration, and wound healing. Often stacked with BPC-157.
    Telomerase
    An enzyme that adds DNA sequence repeats to telomere ends, counteracting chromosomal shortening during cell division. Epithalon activates telomerase.
    Telomere
    Protective caps at the ends of chromosomes that shorten with each cell division. Telomere length is a biomarker of biological aging.
    Tesamorelin →
    A GHRH analog FDA-approved for HIV-associated lipodystrophy. Stimulates natural GH production and reduces visceral fat.
    Tirzepatide →
    A dual GIP/GLP-1 receptor agonist researched for obesity and type 2 diabetes. FDA-approved as Mounjaro/Zepbound.
    Titration
    Gradually increasing a compound dose over time to find the minimum effective dose while minimizing side effects.
    Trophic
    Relating to nutrition, growth, or stimulation. A trophic factor promotes cell growth, survival, or differentiation.
    Trust Score →
    BodyHackGuide's 0–100 vendor rating based on COA verification, payment transparency, community feedback, shipping coverage, and active listings.

    V

    Vasodilation
    Widening of blood vessels, increasing blood flow. Some compounds cause vasodilation as a primary or side effect.
    Vial
    A small glass or plastic container holding lyophilized peptide powder. Common sizes include 2 mg, 5 mg, 10 mg, and 15 mg.