Also called placebo-controlled · control arm
A placebo is an inactive comparator — typically saline injection or sugar pill — administered to the control arm of a trial. Comparing outcomes between the treatment and placebo arms isolates the effect of the drug from expectation, regression to the mean, and other confounders. Placebo-adjusted weight loss is the standard reporting metric in GLP-1 trials.
Research use only. This definition is an educational reference, not medical advice or dosing guidance.