A statistical approach that includes every participant in the analysis according to their originally assigned treatment group, regardless of whether they completed the study, adhered to the protocol, or even received the treatment. If 100 patients are randomized to receive a drug and 20 drop out, all 100 are still counted in the results.

Intention-to-treat (ITT) analysis is considered the gold standard because it preserves the benefits of randomization and reflects real-world conditions where not everyone completes treatment. The alternative—per-protocol analysis, which counts only participants who completed the study as planned—tends to make treatments look more effective than they actually are. When evaluating peptide clinical trial results, check whether ITT or per-protocol analysis was used; the distinction can significantly affect reported efficacy.