# ClinicalTrials.gov API

> ClinicalTrials.gov returns clinical trial records, locations, and sponsor studies as a workflow and API.

Search trials finds studies by condition or medicine, with optional location, distance, recruitment status, and phase filters. Get trial returns a public study record using an NCT number or title, including treatments, arms, locations, and public contacts. List company trials returns studies for a sponsor, with optional phase, status, and condition filters.

- Page: https://fous.com/workflows/clinicaltrials-gov
- Handle: `@clinicaltrials-gov`
- Category: [Health](https://fous.com/workflows/category/health)
- Source website: https://clinicaltrials.gov
- Last verified: Sep 29, 2026
- Fous is not affiliated with ClinicalTrials.gov.

## Methods

### Get trial

Operation `get_trial`, version 1. 1 credit per call.

Get the full public record for a clinical trial by NCT number or title. For ambiguous titles, returns the closest matching registered title. Dates without a recorded day are returned as null.

**Input**

| Field | Type | Required | Example | Description |
|---|---|---|---|---|
| `trial` | string | yes | `"NCT05175625"` | The trial title or NCT trial number, for example NCT04368728. |

**Input schema**

```json
{
  "type": "object",
  "required": [
    "trial"
  ],
  "properties": {
    "trial": {
      "type": "string",
      "description": "The trial title or NCT trial number, for example NCT04368728.",
      "examples": [
        "NCT05175625",
        "NCT04368728",
        "Immunogenicity and Safety of a Booster Dose of the SpikoGen COVID-19 Vaccine"
      ]
    }
  },
  "additionalProperties": false,
  "examples": [
    {
      "trial": "NCT05175625"
    },
    {
      "trial": "NCT04368728"
    },
    {
      "trial": "Immunogenicity and Safety of a Booster Dose of the SpikoGen COVID-19 Vaccine"
    }
  ]
}
```

**Output**

| Field | Type | Example | Description |
|---|---|---|---|
| `arms` | array |  |  |
| `arms[].name` | string or null | `"SpikoGen COVID-19 Vaccine"` |  |
| `arms[].type` | string or null | `"Experimental"` |  |
| `arms[].treatments` | array |  |  |
| `arms[].description` | string or null |  |  |
| `phase` | string or null | `"Phase 3"` |  |
| `title` | string or null | `"Immunogenicity and Safety of a Booster Dose of the SpikoGen COVID-19 Vaccine"` |  |
| `status` | string or null | `"Completed"` |  |
| `sponsor` | string or null | `"Cinnagen"` |  |
| `age_range` | string or null | `"18 Years and older"` |  |
| `locations` | array |  |  |
| `locations[].city` | string or null | `"Tehran"` |  |
| `locations[].country` | string or null | `"Iran"` |  |
| `locations[].facility` | string or null | `"Orchid Life Department, Orchid Pharmed Company"` |  |
| `locations[].recruitment_status` | string or null |  |  |
| `start_date` | string or null | `"2021-12-15"` |  |
| `treatments` | array |  |  |
| `treatments[].arms` | array |  |  |
| `treatments[].name` | string or null | `"SARS-CoV-2 recombinant spike protein + Advax-SM adjuvant"` |  |
| `treatments[].type` | string or null | `"Biological"` |  |
| `treatments[].description` | string or null | `"SARS-CoV-2 recombinant spike protein (25 µg) with Advax-SM adjuvant (15 mg); a single intramuscular injection into the ` |  |
| `trial_link` | string | `"https://clinicaltrials.gov/study/NCT05175625"` |  |
| `trial_number` | string | `"NCT05175625"` |  |
| `official_title` | string or null | `"A Randomized, Two-Armed, Placebo-Controlled, Double-Blind, Parallel-Group Clinical Trial to Evaluate the Immunogenicity` |  |
| `results_posted` | boolean | `false` |  |
| `completion_date` | string or null | `"2022-06-20"` |  |
| `public_contacts` | array |  |  |
| `public_contacts[].name` | string or null |  |  |
| `public_contacts[].role` | string or null |  |  |
| `public_contacts[].email` | string or null |  |  |
| `public_contacts[].phone` | string or null |  |  |
| `public_contacts[].facility` | string or null |  |  |
| `purpose_summary` | string or null |  |  |
| `primary_outcomes` | array |  |  |
| `primary_outcomes[].measure` | string or null | `"Percentage of participants with seroconversion for SARS-CoV-2 neutralizing antibodies"` |  |
| `primary_outcomes[].time_frame` | string or null | `"14 days after the booster dose"` |  |
| `primary_outcomes[].description` | string or null | `"As measured by ELISA"` |  |
| `secondary_outcomes` | array |  |  |
| `secondary_outcomes[].measure` | string or null | `"Incidence of solicited adverse events"` |  |
| `secondary_outcomes[].time_frame` | string or null | `"For 7 days after the booster dose"` |  |
| `secondary_outcomes[].description` | string or null | `"Injection site pain, erythema, swelling, and induration, axillary swelling or tenderness ipsilateral to the side of inj` |  |
| `eligibility_criteria` | string or null |  |  |
| `number_of_participants` | integer or null | `300` |  |

**Example input**

```json
{
  "trial": "NCT05175625"
}
```

**Example output**

```json
{
  "arms": [
    {
      "name": "SpikoGen COVID-19 Vaccine",
      "type": "Experimental",
      "treatments": [
        "Biological: SARS-CoV-2 recombinant spike protein + Advax-SM adjuvant"
      ],
      "description": null
    }
  ],
  "phase": "Phase 3",
  "title": "Immunogenicity and Safety of a Booster Dose of the SpikoGen COVID-19 Vaccine",
  "status": "Completed",
  "sponsor": "Cinnagen",
  "age_range": "18 Years and older",
  "locations": [
    {
      "city": "Tehran",
      "country": "Iran",
      "facility": "Orchid Life Department, Orchid Pharmed Company",
      "recruitment_status": null
    }
  ],
  "start_date": "2021-12-15",
  "treatments": [
    {
      "arms": [
        "SpikoGen COVID-19 Vaccine"
      ],
      "name": "SARS-CoV-2 recombinant spike protein + Advax-SM adjuvant",
      "type": "Biological",
      "description": "SARS-CoV-2 recombinant spike protein (25 µg) with Advax-SM adjuvant (15 mg); a single intramuscular injection into the deltoid muscle of the non-dominant arm"
    }
  ],
  "trial_link": "https://clinicaltrials.gov/study/NCT05175625",
  "trial_number": "NCT05175625",
  "official_title": "A Randomized, Two-Armed, Placebo-Controlled, Double-Blind, Parallel-Group Clinical Trial to Evaluate the Immunogenicity and Safety of a Booster Dose of an Adjuvanted Recombinant Spike Protein COVID-19…",
  "results_posted": false,
  "completion_date": "2022-06-20",
  "public_contacts": [],
  "purpose_summary": "This was a randomized, two-armed, double-blind, placebo-controlled trial designed to evaluate the safety and immunogenicity of a booster dose of an adjuvanted recombinant SARS-CoV-2 spike protein subu…",
  "primary_outcomes": [
    {
      "measure": "Percentage of participants with seroconversion for SARS-CoV-2 neutralizing antibodies",
      "time_frame": "14 days after the booster dose",
      "description": "As measured by ELISA"
    }
  ],
  "secondary_outcomes": [
    {
      "measure": "Incidence of solicited adverse events
…
```

### List company trials

Operation `list_company_trials`, version 1. 1 credit per call.

List studies run or funded by a sponsor, newest start date first. Dates without a full day are returned as null.

**Input**

| Field | Type | Required | Example | Description |
|---|---|---|---|---|
| `phase` | string | no | `"phase_3"` | Study phase to include, such as phase_3; any includes all phases. |
| `status` | string | no | `"recruiting"` | Study recruitment status, such as recruiting; any includes all statuses. |
| `sponsor` | string | yes | `"Pfizer"` | Company or organization sponsoring or collaborating on studies, such as Pfizer. |
| `condition` | string | no | `"obesity"` | Condition to match, such as obesity. |
| `max_results` | integer | no | `10` | Maximum number of studies to return, such as 50 (up to 200). |

**Input schema**

```json
{
  "type": "object",
  "required": [
    "sponsor"
  ],
  "properties": {
    "phase": {
      "enum": [
        "any",
        "phase_1",
        "phase_2",
        "phase_3",
        "phase_4"
      ],
      "type": "string",
      "default": "any",
      "description": "Study phase to include, such as phase_3; any includes all phases.",
      "examples": [
        "phase_3",
        "phase_4"
      ]
    },
    "status": {
      "enum": [
        "any",
        "recruiting",
        "active_not_recruiting",
        "completed"
      ],
      "type": "string",
      "default": "any",
      "description": "Study recruitment status, such as recruiting; any includes all statuses.",
      "examples": [
        "recruiting",
        "completed"
      ]
    },
    "sponsor": {
      "type": "string",
      "minLength": 1,
      "description": "Company or organization sponsoring or collaborating on studies, such as Pfizer.",
      "examples": [
        "Pfizer",
        "ACompanyThatDoesNotExist98364927"
      ]
    },
    "condition": {
      "type": "string",
      "description": "Condition to match, such as obesity.",
      "examples": [
        "obesity"
      ]
    },
    "max_results": {
      "type": "integer",
      "default": 50,
      "maximum": 200,
      "minimum": 1,
      "description": "Maximum number of studies to return, such as 50 (up to 200).",
      "x-fous-developer": true,
      "examples": [
        10
      ]
    }
  },
  "additionalProperties": false,
  "examples": [
    {
      "phase": "phase_3",
      "status": "recruiting",
      "sponsor": "Pfizer",
      "condition": "obesity",
      "max_results": 10
    },
    {
      "sponsor": "Pfizer"
    },
    {
      "phase": "phase_4",
      "status": "completed",
      "sponsor": "ACompanyThatDoesNotExist98364927",
      "condition": "obesity"
    }
  ]
}
```

**Output**

| Field | Type | Example | Description |
|---|---|---|---|
| `trials` | array |  | Matching trials sorted by start date, newest first. |
| `trials[].phase` | string or null | `"Phase 3"` | Study phase or phases in words. |
| `trials[].status` | string or null | `"Recruiting"` | Overall study status in words. |
| `trials[].conditions` | array |  | Conditions studied. |
| `trials[].start_date` | string or null | `"2026-06-10"` | Start date as YYYY-MM-DD when the day is known. |
| `trials[].trial_link` | string | `"https://clinicaltrials.gov/study/NCT07595549"` | ClinicalTrials.gov study page. |
| `trials[].trial_title` | string or null | `"A Study to Learn About the Study Medicine Called Berobenatide (PF-08653944) in People With Overweight or Obesity"` | Public study title. |
| `trials[].trial_number` | string | `"NCT07595549"` | NCT study number. |
| `trials[].number_of_participants` | integer or null | `954` | Enrolled or planned number of participants. |
| `trials[].primary_completion_date` | string or null | `"2028-05-04"` | Primary completion date as YYYY-MM-DD when the day is known. |

**Example input**

```json
{
  "phase": "phase_3",
  "status": "recruiting",
  "sponsor": "Pfizer",
  "condition": "obesity",
  "max_results": 10
}
```

**Example output**

```json
{
  "trials": [
    {
      "phase": "Phase 3",
      "status": "Recruiting",
      "conditions": [
        "Obesity",
        "Overweight and/or Obesity",
        "Overweight"
      ],
      "start_date": "2026-06-10",
      "trial_link": "https://clinicaltrials.gov/study/NCT07595549",
      "trial_title": "A Study to Learn About the Study Medicine Called Berobenatide (PF-08653944) in People With Overweight or Obesity",
      "trial_number": "NCT07595549",
      "number_of_participants": 954,
      "primary_completion_date": "2028-05-04"
    }
  ]
}
```

### Search trials

Operation `search_trials`, version 1. 1 credit per call.

Find ClinicalTrials.gov studies for a condition or medicine, with optional location, distance, recruitment status, and phase filters. With a location, results are ordered by distance to their closest eligible registered site. Site distances are approximate straight-line miles; contact and eligibility information may be missing.

**Input**

| Field | Type | Required | Example | Description |
|---|---|---|---|---|
| `phase` | string | no | `"phase_3"` | Study phase, for example phase_3 or any. |
| `location` | string | no | `"Boston, MA"` | City, state, or country for nearby trials, for example Boston, MA. |
| `condition` | string | yes | `"semaglutide"` | Condition or medicine to search, for example breast cancer or semaglutide. |
| `max_results` | integer | no | `3` | Maximum number of trials to return, for example 20 (up to 100). |
| `distance_miles` | number | no | `50` | Search radius in miles when a location is given, for example 50. |
| `recruiting_only` | boolean | no | `true` | Include only studies recruiting or preparing to recruit, for example true. |

**Input schema**

```json
{
  "type": "object",
  "required": [
    "condition"
  ],
  "properties": {
    "phase": {
      "enum": [
        "any",
        "early_phase_1",
        "phase_1",
        "phase_2",
        "phase_3",
        "phase_4"
      ],
      "type": "string",
      "default": "any",
      "description": "Study phase, for example phase_3 or any.",
      "examples": [
        "phase_3"
      ]
    },
    "location": {
      "type": "string",
      "default": "",
      "description": "City, state, or country for nearby trials, for example Boston, MA.",
      "examples": [
        "Boston, MA"
      ]
    },
    "condition": {
      "type": "string",
      "minLength": 1,
      "description": "Condition or medicine to search, for example breast cancer or semaglutide.",
      "examples": [
        "semaglutide",
        "breast cancer",
        "xxxxunlikelyconditionzxq9876543"
      ]
    },
    "max_results": {
      "type": "integer",
      "default": 20,
      "maximum": 100,
      "minimum": 1,
      "description": "Maximum number of trials to return, for example 20 (up to 100).",
      "x-fous-developer": true,
      "examples": [
        3,
        5,
        4
      ]
    },
    "distance_miles": {
      "type": "number",
      "default": 50,
      "description": "Search radius in miles when a location is given, for example 50.",
      "exclusiveMinimum": 0,
      "examples": [
        50
      ]
    },
    "recruiting_only": {
      "type": "boolean",
      "default": true,
      "description": "Include only studies recruiting or preparing to recruit, for example true.",
      "examples": [
        true
      ]
    }
  },
  "additionalProperties": false,
  "examples": [
    {
      "condition": "semaglutide",
      "max_results": 3
    },
    {
      "phase": "phase_3",
      "location": "Boston, MA",
      "condition": "breast cancer",
      "max_results": 5,
      "distance_miles": 50,
      "recruiting_only": true
    },
    {
      "location": "Boston, MA",
      "condition": "semaglutide",
      "max_results": 4,
      "distance_miles": 50
    }
  ]
}
```

**Output**

| Field | Type | Example | Description |
|---|---|---|---|
| `trials` | array |  |  |
| `trials[].sex` | string or null | `"All"` |  |
| `trials[].phase` | string or null | `"Not applicable"` |  |
| `trials[].status` | string or null | `"Recruiting"` |  |
| `trials[].sponsor` | string or null | `"University College Dublin"` |  |
| `trials[].age_range` | string or null | `"18 Years and older"` |  |
| `trials[].conditions` | array |  |  |
| `trials[].start_date` | string or null | `"2022-06-22"` |  |
| `trials[].trial_link` | string | `"https://clinicaltrials.gov/study/NCT04174755"` |  |
| `trials[].trial_title` | string or null | `"Semaglutide's Efficacy in Achieving Weight Loss for Those With HIV"` |  |
| `trials[].contact_name` | string or null | `"Aoife Cotter, PhD"` |  |
| `trials[].trial_number` | string | `"NCT04174755"` |  |
| `trials[].contact_email` | string or null | `"aoife.cotter@ucd.ie"` |  |
| `trials[].contact_phone` | string or null | `"562-826-8000"` |  |
| `trials[].distance_miles` | number or null | `0.1` |  |
| `trials[].nearest_site_city` | string or null | `"Dublin"` |  |
| `trials[].healthy_volunteers` | boolean or null | `false` |  |
| `trials[].nearest_site_state` | string or null | `"Dublin"` |  |
| `trials[].nearest_site_country` | string or null | `"Ireland"` |  |
| `trials[].nearest_site_facility` | string or null | `"Mater Misericordiae University Hospital"` |  |

**Example input**

```json
{
  "condition": "semaglutide",
  "max_results": 3
}
```

**Example output**

```json
{
  "trials": [
    {
      "sex": "All",
      "phase": "Not applicable",
      "status": "Recruiting",
      "sponsor": "University College Dublin",
      "age_range": "18 Years and older",
      "conditions": [
        "Obesity",
        "HIV-1-infection"
      ],
      "start_date": "2022-06-22",
      "trial_link": "https://clinicaltrials.gov/study/NCT04174755",
      "trial_title": "Semaglutide's Efficacy in Achieving Weight Loss for Those With HIV",
      "contact_name": "Aoife Cotter, PhD",
      "trial_number": "NCT04174755",
      "contact_email": "aoife.cotter@ucd.ie",
      "contact_phone": null,
      "distance_miles": null,
      "nearest_site_city": "Dublin",
      "healthy_volunteers": false,
      "nearest_site_state": "Dublin",
      "nearest_site_country": "Ireland",
      "nearest_site_facility": "Mater Misericordiae University Hospital"
    },
    {
      "sex": "All",
      "phase": "Phase 3",
      "status": "Recruiting",
      "sponsor": "VA Office of Research and Development",
      "age_range": "18 Years to 80 Years",
      "conditions": [
        "Alcohol Use Disorder"
      ],
      "start_date": "2026-07-28",
      "trial_link": "https://clinicaltrials.gov/study/NCT07218354",
      "trial_title": "Cessation or Reduction of Alcohol Consumption in Veterans: A Randomized Controlled Trial for Alcohol Use Disorder (CRAVE)",
      "contact_name": "Larry Albers, MD",
      "trial_number": "NCT07218354",
      "contact_email": "larry.albers@va.gov",
      "contact_phone": "562-826-8000",
      "distance_miles": null,
      "nearest_site_city": "Long Beach",
      "healthy_volunteers": true,
      "nearest_site_state": "California",
      "nearest_site_country": "United States",
      "nearest_site_facility": "VA Long Beach Healthcare System, Long Beach, CA"
    }
  ]
}
```

## Quick start

Call the API with a Fous API key (`FOUS_API_KEY`). To create one, turn on Developer mode in Fous Studio, then open Keys & connections → API keys (https://app.fous.com/keys).

```bash
# First set your key: export FOUS_API_KEY='YOUR_FOUS_API_KEY'
: "${FOUS_API_KEY:?Set FOUS_API_KEY before running this example}"

curl 'https://api.fous.com/v1/query' \
  --fail-with-body --silent --show-error --max-time 120 \
  -H "Authorization: Bearer $FOUS_API_KEY" \
  -H 'Content-Type: application/json' \
  --data-raw '{
  "api": "@clinicaltrials-gov",
  "visibility": "public",
  "operation": "get_trial",
  "version": 1,
  "input": {
    "trial": "NCT05175625"
  },
  "response": {
    "format": "json"
  }
}'
```

```python
# Save as fous.py and run with python3 fous.py. No packages needed.
# First set your key: export FOUS_API_KEY='YOUR_FOUS_API_KEY'
import json
import os
import urllib.error
import urllib.request

api_key = os.environ.get("FOUS_API_KEY")
if not api_key:
    raise RuntimeError("Set FOUS_API_KEY before running this example")

body = json.loads("{\n  \"api\": \"@clinicaltrials-gov\",\n  \"visibility\": \"public\",\n  \"operation\": \"get_trial\",\n  \"version\": 1,\n  \"input\": {\n    \"trial\": \"NCT05175625\"\n  },\n  \"response\": {\n    \"format\": \"json\"\n  }\n}")
request = urllib.request.Request(
    "https://api.fous.com/v1/query",
    data=json.dumps(body).encode("utf-8"),
    headers={
        "Authorization": f"Bearer {api_key}",
        "Content-Type": "application/json",
    },
    method="POST",
)
try:
    with urllib.request.urlopen(request, timeout=120) as response:
        result = json.load(response)
except urllib.error.HTTPError as error:
    raise RuntimeError(f"HTTP {error.code}: {error.read().decode('utf-8', errors='replace')}") from error
if result.get("success") is False:
    raise RuntimeError(result.get("error", {}).get("message", "Request failed"))
print(json.dumps(result["data"]["output"], indent=2))
```

```typescript
// Save as fous.mts and run with npx tsx fous.mts.
// First set your key: export FOUS_API_KEY='YOUR_FOUS_API_KEY'
const apiKey = process.env.FOUS_API_KEY;
if (!apiKey) throw new Error("Set FOUS_API_KEY before running this example");

const response = await fetch("https://api.fous.com/v1/query", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${apiKey}`,
    "Content-Type": "application/json",
  },
  signal: AbortSignal.timeout(120_000),
  body: JSON.stringify({
  "api": "@clinicaltrials-gov",
  "visibility": "public",
  "operation": "get_trial",
  "version": 1,
  "input": {
    "trial": "NCT05175625"
  },
  "response": {
    "format": "json"
  }
}),
});
type ApiResult = { success: boolean; data?: { output: unknown }; error?: { message: string } };
const result: ApiResult = await response.json();
if (!response.ok || result.success === false) {
  throw new Error(result.error?.message ?? `HTTP ${response.status}`);
}
if (!result.data) throw new Error("Missing API response data");
console.log(result.data.output);
```

Or describe the data in plain language: send `{"api":"@clinicaltrials-gov","prompt":"Describe the data you need, with every detail"}` to the same URL. Fous fills in the input, runs the method that fits and returns only the fields you asked for; `data.route.calls[].request` is the exact call it made. Routing is free; the run costs the same.

## Use cases

- Find recruiting trials for a condition near a city
- Review a trial’s treatments, arms, locations, and public contacts
- Compare company studies by phase, status, or condition
- Track study start dates and participant counts by sponsor

## FAQ

### Is Fous affiliated with ClinicalTrials.gov?

No. Fous is not affiliated with ClinicalTrials.gov. This workflow reads the public clinicaltrials.gov website and returns its data.

### How much does it cost?

Each run costs 1 credit. With pay-as-you-go, a credit costs 1¢; monthly plans cost less per credit.

### Do I need a ClinicalTrials.gov account?

No. You only need a Fous account.

### How current is the data?

Fous gets the data from clinicaltrials.gov when you run it; repeating the same request within a day may return the saved result. Fous checks this workflow automatically; it last passed a check on Sep 29, 2026.

### Which trials are recruiting near a location?

Search trials finds studies for a condition or medicine and can filter by location, distance, recruitment status, and phase.

### What treatments and locations are listed for a trial?

Get trial returns a public record with treatments, study arms, locations, and recruitment status by location.

### What studies is a company sponsoring?

List company trials returns studies for a sponsor, with optional filters for phase, status, and condition.

## Related

- [NLM Clinical Tables API](https://fous.com/workflows/nlm-clinical-tables.md): NLM Clinical Tables provides public clinical terminology tables, with diagnosis searches that may miss relevant codes and code explanations checked against current NLM and official classification sources.
- [PubMed API](https://fous.com/workflows/pubmed.md): PubMed searches medical and life-science articles by topic and retrieves one article’s abstract and publication details; abstracts and free full-text links may be unavailable.
- [FDA API](https://fous.com/workflows/fda.md): FDA provides drug safety data, latest matching drug labels, common reported side effects, and newest-first drug, food, and device recalls; recent drug and device recalls may be missing, and weekly food statuses may lag.
- [Mayo Clinic API](https://fous.com/workflows/mayo-clinic.md): Mayo Clinic provides health information from public condition pages, including condition overviews and, where available, diagnosis, treatment, home care, alternative medicine, and appointment preparation.
- [MedlinePlus API](https://fous.com/workflows/medlineplus.md): MedlinePlus provides health information from the U.S. National Library of Medicine, including condition and symptom overviews and explanations of tests with matching pages.
- [Grants.gov API](https://fous.com/workflows/grants-gov.md): U.S. federal grant opportunities and application information.
- [NHS API](https://fous.com/workflows/nhs.md): NHS provides condition and medicine guidance, with condition dates reflecting the latest pages used, and nearby England service listings ordered by distance; availability details may be missing.
- [WebMD API](https://fous.com/workflows/webmd.md): Plain-language health condition and symptom guides from WebMD.
- [All Health workflows](https://fous.com/workflows/category/health)