↳ Definitions · 22

Glossary

Plain-language definitions of the research-peptide and longevity terms used across Peptidoteca — each one a self-contained answer.

Amino acid sequence

An amino acid sequence is the ordered list of amino acid residues that make up a peptide or protein, written from the amino (N) terminus to the carboxyl (C) terminus.

Bacteriostatic water is sterile water containing roughly 0.9% benzyl alcohol, a preservative that inhibits bacterial growth and allows a reconstituted vial to be accessed multiple times in laboratory settings.

Bioavailability

Bioavailability is the fraction of an administered dose of a compound that reaches systemic circulation in an unchanged, active form, expressed as a percentage.

CAS number

A CAS number is a unique numerical identifier assigned by the Chemical Abstracts Service to a specific chemical substance, formatted as up to ten digits in three hyphenated groups (for example 137525-51-0).

Certificate of analysis (COA)

A certificate of analysis (COA) is a document issued by a laboratory that reports the measured quality attributes of a specific batch of material, typically including identity, purity, and the analytical methods used.

GHRH (growth-hormone-releasing hormone)

GHRH (growth-hormone-releasing hormone) is a hypothalamic peptide hormone that binds the GHRH receptor on pituitary somatotroph cells and stimulates the synthesis and release of growth hormone.

GHRP (growth-hormone-releasing peptide)

GHRP (growth-hormone-releasing peptide) is a class of synthetic secretagogues that act as agonists at the ghrelin receptor (GHS-R1a) to stimulate growth-hormone release from the pituitary.

Growth-hormone secretagogue

A growth-hormone secretagogue is any molecule that stimulates the pituitary gland to secrete growth hormone, acting at either the ghrelin receptor (GHS-R1a) or the GHRH receptor.

Half-life

Half-life is the time required for the concentration of a compound in a biological system to fall to one half of its initial value, denoted t½.

HPLC purity

HPLC purity is a measure of how much of a sample is the target compound, determined by high-performance liquid chromatography, which separates components by their differing affinities for a column and reports each as a percentage of total peak area.

In vitro

In vitro is a Latin term, meaning "in glass," that describes experiments performed outside a living organism, in a controlled environment such as a test tube, culture dish, or cell-free system.

Lyophilization

Lyophilization, also called freeze-drying, is a preservation process that removes water from a frozen material by sublimation under vacuum, leaving a dry, stable powder.

Mass spectrometry

Mass spectrometry is an analytical technique that ionizes a sample and measures the mass-to-charge ratio of the resulting ions, producing a spectrum used to determine molecular weight and confirm identity.

Molecular weight

Molecular weight is the mass of a molecule, calculated as the sum of the atomic weights of all its constituent atoms and expressed in daltons (Da) or grams per mole.

Pentadecapeptide

A pentadecapeptide is a peptide composed of exactly fifteen amino acid residues joined by peptide bonds.

Peptide

A peptide is a short chain of amino acids linked by peptide bonds, conventionally distinguished from a protein by its smaller size, often defined as fewer than about fifty residues.

Peptide bond

A peptide bond is the covalent amide bond that links two amino acids, formed when the carboxyl group of one reacts with the amino group of another and releases a molecule of water in a condensation reaction.

Preclinical research

Preclinical research is the stage of scientific investigation that takes place before any testing in humans, using in vitro systems and animal models to characterize a compound's biological activity, mechanism, and safety profile.

Receptor agonist

A receptor agonist is a molecule that binds a specific cellular receptor and activates it, producing a biological response that mimics the receptor's natural ligand.

Reconstitution

Reconstitution is the laboratory process of dissolving a lyophilized (freeze-dried) powder back into a liquid by adding a measured volume of a diluent such as bacteriostatic or sterile water.

Research use only (RUO)

Research use only (RUO) is a labeling and regulatory designation indicating that a material is intended exclusively for laboratory research and is not approved, evaluated, or sold for diagnostic, therapeutic, or human or veterinary use.

Subcutaneous

Subcutaneous describes the tissue layer beneath the skin and, in pharmacology, an administration route in which a substance is deposited into that layer rather than into muscle or a vein.