ClinicalTrials.gov Study Lookup

Look up any registered clinical trial by NCT ID against the official, free ClinicalTrials.gov v2 API run by the U.S. National Institutes of Health — status, phase, sponsor, enrollment, conditions, interventions, and trial site countries. No API key, no scraping — this hits the official government API directly.

Features

• NCT ID → full protocol record. Brief and official title, overall status, phase, study type, start/completion dates.
• Sponsor & scale. Lead sponsor name and target enrollment count.
• Clinical detail. Conditions studied, interventions (with type: drug, device, behavioral, etc.), and location countries with site count.
• Pay only for hits. NCT IDs that don't resolve cost nothing — see Pricing.
• Built for bulk. Feed in thousands of NCT IDs; concurrency, keyword filtering, and column selection are all configurable.

How to use ClinicalTrials.gov Study Lookup — Official NIH Registry API

1. In the Apify Console. Open the actor page and click Start — the nctIds field is already pre-filled with a working example. Results land in the run's dataset as soon as each item is found.
2. Via the API. Call it directly with a POST request — no Console needed once you have an API token:

   curl "https://api.apify.com/v2/acts/accountable_eel~clinicaltrials-study-lookup/run-sync-get-dataset-items?token=<YOUR_TOKEN>" \
     -X POST \
     -H "Content-Type: application/json" \
     -d '{"nctIds":["NCT04280705"]}'
   

3. On a schedule. Save this actor as an Apify Task with the input you want, then add a Schedule (hourly, daily, weekly) so it runs on its own — no server of your own required.

Input

{
  "nctIds": [
    "NCT04280705"
  ]
}

One NCT ID per line, e.g. NCT04280705. Accepted formats: NCT04280705.

{
  "nctIds": ["NCT04280705"],
  "testRun": false,
  "onlyFound": false,
  "maxConcurrency": 5
}

nctIds is a list of ClinicalTrials.gov identifiers (format NCT followed by 8 digits, e.g. NCT04280705). One dataset row is returned per ID; rows with "found": false are never charged. Turn on testRun to try your list against just the first 5 IDs before running the full batch. Optional includeKeywords / excludeKeywords filter rows by content, maxResults caps the run early, and columns lets you pick which fields to return.

Output

One row per NCT ID, for example:

{
  "query": "NCT04280705",
  "found": true,
  "status": "OK",
  "nctId": "NCT04280705",
  "title": "Adaptive COVID-19 Treatment Trial (ACTT)",
  "officialTitle": "A Multicenter, Adaptive, Randomized Blinded Controlled Trial of the Safety and Efficacy of Investigational Therapeutics for the Treatment of COVID-19",
  "overallStatus": "COMPLETED",
  "startDate": "2020-02-21",
  "completionDate": "2021-04-19",
  "phase": "PHASE3",
  "studyType": "INTERVENTIONAL",
  "enrollment": 1062,
  "leadSponsor": "National Institute of Allergy and Infectious Diseases (NIAID)",
  "conditions": ["Covid19"],
  "interventions": [{ "type": "DRUG", "name": "Remdesivir" }],
  "locationCountries": ["United States", "South Korea", "Japan"],
  "locationCount": 60,
  "briefSummary": "A randomized, placebo-controlled trial evaluating investigational therapeutics for COVID-19...",
  "scrapedAt": "2026-08-21T10:00:00.000Z"
}

NCT IDs that don't resolve still get a row ("found": false, "status": "NOT_FOUND" or "BAD_FORMAT", with a plain-English message), so you always get one row per input — but you're never charged for those.

Use cases

• Trial status monitoring — track a watchlist of NCT IDs for status changes (recruiting → active → completed) across a therapeutic area.
• Competitive intelligence — pull sponsor, phase, and enrollment for a set of trials in a given condition or drug class.
• Site & country coverage analysis — see which countries a trial recruits in and how many sites it runs, without opening each record.
• Regulatory & literature enrichment — attach structured trial metadata to a publication or citation dataset that already references NCT IDs.

Pricing

$4 per 1,000 studies, plus a $0.00005 start fee. Misses (found:false) are never charged.

Use it from Clay, n8n, Make, or an AI agent

This actor runs synchronously over plain HTTP — call it directly from a script, a workflow tool, or an AI agent, no Apify Console needed once you have an API token.

curl "https://api.apify.com/v2/acts/accountable_eel~clinicaltrials-study-lookup/run-sync-get-dataset-items?token=<YOUR_TOKEN>" \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{"nctIds":["NCT04280705"]}'

n8n. Add an HTTP Request node: Method POST, URL https://api.apify.com/v2/acts/accountable_eel~clinicaltrials-study-lookup/run-sync-get-dataset-items?token=<YOUR_TOKEN>, Body Content Type JSON, JSON Body {"nctIds":["NCT04280705"]} (swap in an expression from an earlier node for a real value).

Clay. Add an "HTTP API" column: Method POST, URL https://api.apify.com/v2/acts/accountable_eel~clinicaltrials-study-lookup/run-sync-get-dataset-items?token=<YOUR_TOKEN>, Body {"nctIds":["{{study}}"]}, mapping the row's study into the nctIds array.

MCP. In Claude, Cursor, or any MCP client with the Apify MCP server, ask for "ClinicalTrials.gov API — Study Protocol & Status Lookup" — the agent will find and run this actor.

FAQ

Do I need a ClinicalTrials.gov API key? No. The ClinicalTrials.gov v2 API is free and public — this actor calls it directly, with no credentials required on your end.

What counts as "not found"? A well-formed NCT ID with no matching study returns "found": false" with

"status": "NOT_FOUND"

What ID format does it expect? NCT followed by exactly 8 digits, e.g. NCT04280705. The actor extracts the NCT pattern from your input automatically, so pasting a longer string containing a valid ID still works.

Does phase cover trials with multiple phases? Yes — some trials span more than one phase (e.g. Phase 2/3). When that's the case, phase returns a comma-separated list, e.g. "PHASE2, PHASE3".

Can I run this against thousands of NCT IDs at once? Yes. Turn on testRun first to sanity-check your list against just 5 IDs, then run the full batch — maxConcurrency controls how many requests run in parallel.

Is this limited to U.S. trials? No — ClinicalTrials.gov indexes trials registered from sponsors and sites worldwide. Use locationCountries in each result to see which countries a given trial actually recruits in.