Glossary · 37 definitions

Plain words for research terms.

Each entry shows the exact term first, then gives its simple meaning. Choose a letter or search for a word.

A

Active ingredient: The part of a drug intended to cause its main effect. Its name alone does not tell you what the whole product is.
Adverse event: A health problem reported after someone receives a product. It may not have been caused by the product.
Agonist: A substance that turns on a body signal. It activates a receptor. This shows how it may work, not that it helps patients.
Alias: Another name for a molecule or product. Different names may hide changes in sequence, chemical form, or finished product.
Approved indication: The exact use a regulator reviewed for one drug product. It includes the condition, people, and product.

Biomarker: A body measurement, such as a hormone level. It can show activity without showing that patients feel or function better.
Blinding: A study method that keeps some people from knowing which treatment they received. This can reduce expectation and measurement bias.

Clinical outcome: A result that matters in a person's life or care. It covers how a person feels, functions, survives, or uses healthcare, not only a laboratory change.
Compounded drug: A drug made for a named patient or under compounding rules. It is not FDA-approved or reviewed before marketing for safety, effectiveness, or quality.
Comparator: What a treatment is compared with in a study. It can be a placebo, usual care, or another active drug.
Confidence interval: A range that shows how uncertain a study estimate is. A narrower range usually means the estimate is more precise.

Endpoint: The result a study plans to measure. Primary, secondary, and exploratory endpoints do not all carry the same weight.
Evidence transfer: Using a result from one situation to support a different one. To do this safely, check the molecule, product, route, people, and result.

Formulation: The finished form of a drug, not only its main ingredient. It includes the active ingredient, amount, inactive ingredients, route, and physical form.

Human pharmacology: How a substance changes the body in people. It can include exposure, receptor activity, hormone changes, and other body measures. It does not by itself show a health benefit.

Immunogenicity: The chance that a substance makes the immune system react. Clumping, changes to the molecule, impurities, route, and storage can affect this risk.
Investigational: Still being studied. It does not mean approved, proven, or available for routine self-treatment.

Mechanism: How a substance may work in the body. This can explain a biological process, but it is not proof of a health benefit.

Observational study: A study that watches what happens without assigning people to groups by chance. It can show links but cannot rule out other explanations.

Peptide: A short chain of amino acids, the building blocks of proteins. The word can describe natural signals, approved medicines, research molecules, and unverified products.
Pharmacodynamics: What a substance does to the body. It can include receptor activity, hormone release, and other body responses.
Pharmacokinetics: What the body does to a substance over time. It includes how the body absorbs, moves, changes, and removes it.
Placebo: A comparison treatment that may not contain an active drug. It helps estimate how much of a result came from the drug rather than expectation, illness changes, or taking part in the study.
Preclinical: Research in cells, tissues, or animals before testing in people.
Primary source: The original record, not someone else's summary. It can be a regulator's record, trial report, registry result, or study publication.
Product certainty: How sure the evidence is about what the product actually is. It covers identity, quality, formulation, route, storage, and how the product was made and checked.

Randomization: Putting study participants into groups by chance. This helps reduce systematic differences and other explanations for the results.
Registration: A public record of a study plan. It does not prove that a trial finished or had a positive result.
RETA peptide (retatrutide): An online nickname for retatrutide (LY3437943), one investigational molecule. The molecule activates glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), and glucagon receptors. The nickname is not an approved product name and does not show what a product sold online contains or its purity or quality.
Route of administration: How a product enters the body. It includes oral (by mouth), topical (on the skin), subcutaneous (under the skin), and intravenous (into a vein) routes. Evidence and risk can change with the route.

Salt form: A chemical form that can affect how a substance is handled or stays stable. Free base and acetate are examples; they are not identical without supporting tests.
Scope: What a conclusion covers. It includes the people, product, route, result, comparison, and time period.
Sequence: The order of amino acids in a peptide. A fragment, change, or extra chemical group can make a different thing to study.
Statistical significance: A test result that is unlikely to be explained by chance under a stated model. It does not show that an effect is large, important, unbiased, or reproducible.
Systematic review: A planned review that finds and assesses all relevant studies on one question.

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

UNII: A Unique Ingredient Identifier, or UNII, is a code used in an FDA system to identify a substance. It does not mean a drug is approved.