Randomized Controlled Trial

A randomized controlled trial (RCT) is a prospective experimental study design in which participants are randomly allocated to receive either the intervention under investigation or a control condition (placebo, standard care, or active comparator). Randomisation minimises selection bias and ensures that both known and unknown confounding variables are distributed evenly across groups, enabling causal inference about treatment effects. RCTs progress through defined phases: phase I evaluates safety and dosing in small cohorts, phase II assesses efficacy and side effects in larger groups, phase III confirms effectiveness in large populations, and phase IV monitors long-term outcomes post-approval. Key design features that strengthen an RCT include double-blinding, intention-to-treat analysis, adequate statistical power, and pre-registered primary endpoints. In peptide research, landmark RCTs include the SURPASS and SURMOUNT trials for tirzepatide, which demonstrated statistically significant improvements in glycaemic control and body weight reduction, leading to regulatory approvals.