The practical answer
A ClinicalTrials.gov record tells you whether a study was registered, its phase, who sponsors it, its recruitment status, how many people it planned or actually enrolled, and whether results were posted. It does not tell you whether a product works or is approved. Check the status, phase, last update and record verification dates, and the results flag before accepting any claim that a peptide is in clinical trials.
Evidence, method & source dates ↓Why read the registry yourself
Supplier pages and forum posts often say a peptide is "in clinical trials". That phrase can mean anything from a withdrawn registration to a completed phase 3 programme with posted results. A ClinicalTrials.gov record lets you check which, in a few minutes, from fields the sponsor or responsible party must keep current under federal rules for applicable trials. [4] [5]
This guide is about reading the record. It makes no claims about the benefit or safety of any peptide, and a registry entry is not evidence of either. For the research literacy steps that come after the registry, see the related guides.
The fields that matter, in order
The field names below are those used in the ClinicalTrials.gov data and API; the definitions come from the federal rule at 42 CFR Part 11 where it defines them. [1] [3] [4]
| Field | What it means | What to check |
|---|---|---|
| NCT number | The registry identifier for the study [2] | Any claim should cite one; search it directly |
| Study type | Interventional, observational or expanded access [1] | Observational studies do not assign an intervention |
| Study phase | For drug trials, the numerical phase consistent with FDA rules [4] | See the phase table below; Not Applicable is also a valid value [1] |
| Overall recruitment status | Status of the trial as a whole; if any site is recruiting, it must be recruiting [4] | Withdrawn, suspended or terminated studies did not run as planned |
| Why study stopped | A brief reason for suspended, terminated or withdrawn trials [4] | Read it; it is often one line |
| Lead sponsor | The organisation or person who initiates the study and has authority and control over it [3] | Is it a drug company, a university, or a clinic? |
| Enrollment | Estimated target number, or the actual number once primary completion is reached [4] | Actual vs Anticipated label [1] |
| Start, primary completion, study completion dates | Primary completion is when the last participant was examined for the primary outcome; study completion adds secondary outcomes and adverse events [4] | Estimated dates in the past are a staleness signal |
| Record verification date | When the responsible party last verified the record, even with no changes [4] | Part 11 requires review at least every 12 months for applicable trials [5] |
| Has results | Flag showing whether results are posted on the public site [3] | No results is not the same as negative results |
Status values and what they tell you
The registry uses a fixed list of overall status values for studies, plus separate values for expanded access programmes. [1] Under 42 CFR 11.64, a change in overall recruitment status must be reported within 30 calendar days, and a reason must be given when a study is suspended, terminated or withdrawn. [5]
One value is set by the registry rather than the sponsor. ClinicalTrials.gov describes an Unknown status study as one whose last known status was recruiting, not yet recruiting, or active, not recruiting, that has passed its completion date and has not been verified within the past 2 years. [3]
| Status | Plain reading |
|---|---|
| Not yet recruiting | Registered, not started enrolling [1] |
| Recruiting | Enrolling now [1] |
| Enrolling by invitation | Enrolling selected participants only [1] |
| Active, not recruiting | Running, no longer enrolling [1] |
| Completed | Ended as planned; check for results [1] |
| Suspended | Paused; read Why Stopped [1] [4] |
| Terminated | Stopped early; read Why Stopped [1] [4] |
| Withdrawn | Listed as withdrawn; read Why Stopped [1] [4] |
| Unknown status | Past its completion date and not verified for 2 years [3] |
Phase is a stage, not a result
The registry phase values are Not Applicable, Early Phase 1, Phase 1, Phase 2, Phase 3 and Phase 4. [1] FDA's patient-facing description of drug development gives typical sizes and purposes for phases 1 to 4. [7]
- Phase 1 studies are not "applicable drug clinical trials" under 42 CFR 11.10, so the Part 11 duties for applicable drug trials do not cover them. [4]
- A phase label tells you where a programme was, not that it succeeded. FDA's own figures show most drugs do not progress through every phase. [7]
| Phase | Typical participants (FDA) | Typical length (FDA) | Purpose (FDA) | Share moving on (FDA) |
|---|---|---|---|---|
| 1 | 20 to 100 healthy volunteers or people with the condition [7] | Several months [7] | Safety and dosage [7] | About 70% [7] |
| 2 | Up to several hundred people with the condition [7] | Several months to 2 years [7] | Efficacy and side effects [7] | About 33% [7] |
| 3 | 300 to 3,000 volunteers with the condition [7] | 1 to 4 years [7] | Efficacy and monitoring of adverse reactions [7] | About 25 to 30% [7] |
| 4 | Several thousand [7] | Not stated [7] | Safety and efficacy [7] | Not applicable |
Results: when they should appear
For applicable clinical trials, 42 CFR 11.44 sets the standard deadline for results at no later than 1 year after the primary completion date. A sponsor seeking approval of a new use may certify for a delay, but results are still due no later than 2 years after that certification. [6] Record information must also be updated at least every 12 months. [5]
So a phase 2 or 3 drug trial that completed several years ago with no results and an old verification date deserves a question. Not every registered study is an applicable clinical trial, though, so a missing result is a prompt to look further, not proof of anything.
Worked example: reading one record
NCT03548935 is a sponsor-registered peptide drug trial, used here only to show how the fields fit together. On 30 October 2026 the registry API returned these values. [2]
| Field | Value on 30 October 2026 | Reading |
|---|---|---|
| Brief title | STEP 1: Research Study Investigating How Well Semaglutide Works in People Suffering From Overweight or Obesity [2] | Names the investigational product |
| Lead sponsor | Novo Nordisk A/S [2] | A drug manufacturer, not a clinic |
| Study type and phase | Interventional, Phase 3 [2] | Late-stage drug trial |
| Overall status | Completed [2] | Ended; look for results |
| Enrollment | 1,961, Actual [2] | Real enrollment, not a target |
| Start and primary completion | 4 June 2018 and 30 March 2020 [2] | Results due within a year of primary completion for applicable trials [6] |
| Results first posted | 11 August 2021 [2] | Results are on the record |
| Last update posted and verified | 19 November 2021; verified November 2021 [2] | Normal for a completed study with results |
Checklist for an "in clinical trials" claim
Run these checks before repeating or relying on the claim. Record the NCT number and the date you checked, since records change.
- Is there an NCT number, and does the record name the same molecule, not a related one?
- Who is the lead sponsor, and is it connected to the seller making the claim?
- What is the status, and if stopped, what does Why Stopped say?
- What phase, and is enrollment Actual or Anticipated?
- When was the record last verified, and are estimated dates already in the past?
- Are results posted, and if the primary completion date is more than a year old, why not?
- Does any of this say the product is approved? It cannot. Approval is checked with FDA, not the registry.
Questions before you decide
Does a ClinicalTrials.gov listing mean a peptide is approved?
No. A record shows a study was registered and how it is progressing; approval status is a separate FDA question.
What does Unknown status mean on ClinicalTrials.gov?
The registry uses it for a study whose last status was active or recruiting, that passed its completion date and was not verified in the past 2 years.
When should results appear for a completed trial?
For applicable clinical trials, 42 CFR 11.44 sets the standard deadline at no later than 1 year after the primary completion date, with limited delays.
What is the difference between Actual and Anticipated enrollment?
Anticipated is the estimated target number; 42 CFR 11.10 requires the actual number once the trial reaches its primary completion date.
Check the underlying evidence
Sources & review dates
- ClinicalTrials.gov API: study field enumerations (status, phase, study type, enrollment type) ↗Accessed 30 Oct 2026
- ClinicalTrials.gov API: record NCT03548935, selected fields ↗Accessed 30 Oct 2026
- ClinicalTrials.gov API: study data metadata and field descriptions ↗Accessed 30 Oct 2026
- Cornell LII: 42 CFR 11.10, Definitions and data element definitions ↗Accessed 30 Oct 2026
- Cornell LII: 42 CFR 11.64, Updates to clinical trial information ↗Accessed 30 Oct 2026
- Cornell LII: 42 CFR 11.44, Deadlines for submitting results ↗Accessed 30 Oct 2026
- US FDA: Step 3, Clinical Research ↗Accessed 30 Oct 2026
Sources are documentary evidence. They do not establish firsthand testing of a listed supplier.