Glossary · 37 definitions

The language behind the evidence.

Short definitions with the boundary intact. Use search for a concept or jump by letter.

A

Active ingredient: The component intended to produce a drug's effect. An ingredient name is not a complete product identity.
Adverse event: An unfavorable medical occurrence after exposure. It is not automatically caused by the intervention, but it must be recorded and evaluated.
Agonist: A molecule that activates a receptor. Receptor activation establishes a mechanism, not necessarily a useful patient outcome.
Alias: Another name used for a molecule or product. Aliases can hide important differences in sequence, salt form, modification, or formulation.
Approved indication: A specific use, population, and condition reviewed by a regulator for a particular drug product.

Biomarker: A measured biological signal such as a hormone level. A biomarker can support biological activity without proving that patients feel or function better.
Blinding: A study method that limits knowledge of treatment assignment to reduce expectation and measurement bias.

Clinical outcome: An outcome that reflects how a person feels, functions, survives, or uses healthcare, rather than only a laboratory change.
Compounded drug: A drug prepared for an identified patient or under other compounding provisions. Compounded drugs are not FDA-approved and are not premarket-reviewed for safety, effectiveness, or quality.
Comparator: The group or intervention against which a treatment is tested, such as placebo, usual care, or another active drug.
Confidence interval: A range that expresses statistical uncertainty around an estimate. Narrower intervals usually indicate greater precision.

Endpoint: A prespecified measurement used to judge a study result. Primary, secondary, and exploratory endpoints carry different evidentiary weight.
Evidence transfer: Applying a result from one molecule, product, route, population, or endpoint to another. Transfer requires evidence, not just similarity.

Formulation: The complete drug preparation, including active ingredient, concentration, excipients, route, and physical form.

Human pharmacology: Evidence that a substance changes exposure, receptor activity, hormones, or other biological measures in people. It does not by itself establish clinical benefit.

Immunogenicity: The potential for a substance or impurity to trigger an immune response. Peptide aggregation, modifications, impurities, route, and storage can affect risk.
Investigational: Being studied for possible use. Investigational does not mean approved, proven, or available for routine self-treatment.

Mechanism: A proposed or demonstrated biological process. Mechanistic plausibility is an early rung on the evidence ladder.

Observational study: A study that observes exposure and outcomes without random assignment. It can reveal associations but is more vulnerable to confounding.

Peptide: A chain of amino acids. The category includes natural signals, approved medicines, research molecules, and unverified products.
Pharmacodynamics: What a substance does to the body, including receptor activity, hormone release, or other measured responses.
Pharmacokinetics: How the body absorbs, distributes, metabolizes, and eliminates a substance over time.
Placebo: An inactive or comparison intervention used to estimate effects beyond expectation, natural history, and study participation.
Preclinical: Research conducted before or outside human clinical testing, commonly in cells, tissues, or animals.
Primary source: The original regulatory record, trial report, registry result, or study publication rather than a summary or promotional retelling.
Product certainty: Confidence that the material being discussed has known identity, quality, formulation, route, storage, and manufacturing controls.

Randomization: Assigning participants to study groups by chance to reduce systematic differences and confounding.
Registration: A public study plan. Registration improves transparency but is not proof that a trial was completed or produced a positive result.
RETA (retatrutide): RETA is informal online shorthand for retatrutide (LY3437943), an investigational single molecule that activates GIP, GLP-1, and glucagon receptors. The nickname is not an approved product name and cannot establish the identity, purity, or quality of material sold online.
Route of administration: How a product enters the body, such as oral, topical, subcutaneous, or intravenous. Evidence and risk can change materially by route.

Salt form: A chemical form used to affect stability or handling. Free base and acetate forms should not be treated as identical without supporting characterization.
Scope: The population, product, route, endpoint, comparator, and duration to which a conclusion applies.
Sequence: The ordered amino-acid chain of a peptide. A fragment, modification, or extra chemical group can create a different evidence object.
Statistical significance: Evidence that a result is unlikely under a specified null model. It does not establish that the effect is large, important, unbiased, or reproducible.
Systematic review: A structured effort to find, appraise, and synthesize all eligible studies for a defined question.

Trial registry: A public record of a study's planned methods and status. Results must still be checked separately.

UNII: A Unique Ingredient Identifier used by FDA's substance-registration system. A UNII identifies a substance and does not imply approval.