Glossary.

A short chain of amino acids linked by peptide bonds.

A large amino-acid chain that folds into a functional 3-D structure.

A molecule that activates a receptor to produce a response.

A molecule that blocks a receptor without activating it.

A modified version of a molecule designed to alter its properties.

A portion of a larger peptide or protein.

Produced naturally within the body.

A protein that binds a signalling molecule and triggers a cellular response.

The time for the amount of a compound in the body to fall by half.

The fraction of a dose that reaches systemic circulation in active form.

How the body absorbs, distributes, metabolizes, and clears a compound.

What a compound does to the body: its effects and mechanism.

A study that randomly assigns participants to treatment or control.

A statistical synthesis of results from multiple studies.

A structured review that gathers and appraises all relevant studies.

Research in cells or animals, before human trials.

Experiments performed in cells or test tubes, outside a living organism.

Experiments performed in a living organism.

The specific biochemical way a compound produces its effect.

Glucagon-like peptide-1, an incretin hormone affecting insulin and appetite.

Glucose-dependent insulinotropic polypeptide, another incretin hormone.

Growth-hormone-releasing hormone, which stimulates GH secretion.

Growth-hormone-releasing peptides, which act on the ghrelin receptor.

Insulin-like growth factor 1, a mediator of growth-hormone effects.

Gut hormones (GLP-1, GIP) that boost insulin after eating.

A substance that triggers secretion of another substance.

The formation of new blood vessels.

Dissolving a lyophilized (freeze-dried) peptide into liquid for research use.

Freeze-dried for stability.

A lab document reporting a batch's identity and purity tests.

High-performance liquid chromatography, used to assess purity.

A technique that measures molecular mass to confirm identity.

Bacterial cell-wall components that can cause harmful reactions.

The proportion of a sample that is the intended compound.

An unwanted medical occurrence during use of a compound.

A condition that makes a treatment inadvisable.

Gradually adjusting a dose to a target.

The World Anti-Doping Agency, which sets the prohibited-substance list.

U.S. authorization to market a drug for specific indications.

Labeled for laboratory research, not human use.

A protein that regulates the opening of intestinal tight junctions.

A protein that limits skeletal muscle growth.

Gonadotropin-releasing hormone, the top of the reproductive hormone axis.

The share of a vial's mass that is actual peptide rather than salts and water.

A drug developed for a rare disease under special regulatory incentives.

A required FDA safety programme attached to certain higher-risk drugs.

A pharmacy that prepares customized medications for individual prescriptions.

A rapid loss of response to a compound after repeated exposure.

Improvement that follows an inert treatment or the act of being treated.

The protein seal between adjacent cells that controls what passes between them.

A measurable indicator used to track a biological state or response.

An engineered molecule that binds a signalling protein before it reaches its receptor.

A muscle stem cell that supports repair and growth of muscle fibres.

A marketing and research-programme label, not an established pharmacological class.