Randomized controlled trial (RCT)
Participants are allocated to study groups by a random process, reducing allocation bias. Randomization does not guarantee a large, well-powered or clinically relevant study.
RESEARCH GLOSSARY
Read the literature without the hype.
Plain-language definitions used throughout the WILGO Research Index.
Double-blind
Typically means participants and specified study personnel do not know assignment. The exact masking roles should be checked in the paper or registry.
Placebo-controlled
An intervention is compared with an inactive or matched control intended to isolate the effect of the intervention.
Pharmacokinetics (PK)
What the body does to a compound: absorption, distribution, metabolism, elimination and exposure over time.
Pharmacodynamics (PD)
What a compound does to the body or a measured biological system, such as a hormone or biomarker response.
Clinical efficacy endpoint
An outcome intended to measure whether an intervention improves a clinically meaningful condition or function.
Biomarker
A measured biological characteristic. A biomarker change can be important without proving a clinical benefit.
Observational study
Researchers observe exposures or characteristics without random assignment. Associations do not automatically establish causation.
Case series
A descriptive report of multiple cases without a randomized comparator. Useful for signals; weak for causal efficacy claims.
In vivo
Research performed in a living organism, commonly an animal model in preclinical peptide literature.
In vitro
Research performed outside a living organism, such as cultured cells or biochemical systems.
Ex vivo
Research on tissue or organs removed from an organism and studied outside the body.
Review article
A synthesis of existing literature. Reviews are useful maps but are not substitutes for the underlying primary studies.
Preclinical
Research conducted before or outside definitive human clinical testing, commonly involving cells, tissues or animals.
Statistical significance
A statistical threshold describing compatibility with a null hypothesis under a model. It is not the same as clinical importance.
Primary source
The original study, trial registry, database record or authoritative document rather than a secondary summary.