Clinical Trial Phases
Clinical trial phases are the ordered steps of human testing for a new compound: Phase 1 checks safety in a small group, Phase 2 looks for an effect, and Phase 3 confirms it in a large group. A compound must pass each phase before regulators consider approval.
Where the word comes from
“Clinical” traces to the Greek klinē, “bed” — klinikos meant “at the bedside,” medicine observed in real patients rather than in theory. “Phase” comes from the Greek phasis, “appearance,” the same root as the phases of the moon: stages that show up one after another. The numbered-phase framework became standard in the mid-1900s, when drug law began requiring staged proof of safety and effectiveness before approval.
What it means here
Our research pages report where a compound sits in this pipeline, so the phase names appear often. “Completed a Phase 1 trial” means a small group of people received the compound so researchers could study safety — nothing more. Most peptides in this catalog have only preclinical or early-phase data. A few are related to pharmaceutical programs that finished Phase 3 and reached approval; after approval, Phase 4 monitoring continues in the general population. Knowing the phases makes those trial summaries much easier to read.
Words you’ll see together
- placebo — an inactive comparator given to part of a study group
- randomized — participants are assigned to study groups by chance
- double-blind — neither participants nor study staff know the group assignments until the trial ends
- endpoint — the outcome a trial is designed to measure
- participants — the people enrolled in a trial
Related terms
- Preclinical — the lab and animal research stage that comes before Phase 1
- FDA approval status — what completing the phases can lead to
- PubMed / DOI — where published trial results are found and cited
Where it appears in our catalog
- Retatrutide — the product page reports published early-phase trial data
- Tesamorelin — a compound whose related pharmaceutical program completed late-phase trials
References
- U.S. Food and Drug Administration — The Drug Development Process, Step 3: Clinical Research: fda.gov/patients/drug-development-process/step-3-clinical-research
