Blinding (Masking)
The practice of concealing treatment assignment from participants, investigators, or both to prevent bias. Single-blind means participants are unaware; double-blind means both participants and investigators are unaware. Triple-blind additionally conceals assignment from data analysts.
Technical Context
Blinding challenges for peptide drug trials: injectable drugs require matched placebo devices (same pen type, appearance, injection procedure), different injection frequencies between drugs require dummy dosing schedules (double-dummy design — e.g. comparing daily vs weekly injection requires the daily group to receive weekly placebo and the weekly group to receive daily placebo), and distinctive side effects (GLP-1 RA nausea) may functionally unblind participants. Blinding assessment: some trials include questionnaires asking participants to guess their treatment assignment — if guessing accuracy significantly exceeds 50%, functional unblinding may have occurred. Central adjudication of endpoints (blinded committee reviews de-identified data) provides an additional layer of bias protection regardless of participant-level blinding.