How to find clinical studies

Start with an official study registry

Use ClinicalTrials.gov for U.S. records and many international records submitted under applicable registration rules and voluntary submissions. It is not a complete global registry. Search by one condition or topic first. Add a location radius that you can sustain across the full study, then filter for studies that are recruiting or will recruit.

ClinicalTrials.gov recommends (opens in a new tab) using one condition at a time and applying the status and location filters that matter. A broad first search helps you learn the terms sponsors use. A narrow search can hide relevant records when the condition name, intervention name, or location spelling differs from your wording.

For international research, use the WHO International Clinical Trials Registry Platform (opens in a new tab) or the relevant national or regional registry. For cancer studies, use the National Cancer Institute’s trial search as a second official source. For studies at the NIH Clinical Center, use NIH’s Search the Studies database. Disease organizations and research networks can provide leads, but trace each lead back to the sponsor, institution, or registry record before sharing personal information.

Choose location, age, and study filters

Apply filters that determine whether participation can happen: age, sex when relevant to eligibility, study status, distance, study type, intervention, and phase. Do not over-filter on a first pass. Eligibility sections summarize protocol rules and may omit operational details used during prescreening.

Open promising records in separate tabs and record the NCT number before reading a sponsor page. Sort your notes by location, expected duration, and study type. Mark words you need to define, including randomized, masking, crossover, observational, expanded access, and interventional.

Separate overall status from local status

A study can recruit somewhere while the location near you has closed, paused, filled its cohort, or not opened. Read the Contacts and Locations section. Look for the facility, city, country, and location-level recruitment status. Some records provide one central contact instead of a contact for each location.

When contact information is missing, ClinicalTrials.gov notes (opens in a new tab) that the study may not be actively recruiting, may use a central contact, or may have outdated location details. Ask the institution’s main switchboard to connect you to its research office. Do not infer that a text-message number belongs to a listed site.

Check the record date and history

Read “Last Update Posted” near the top of the record. Then open Record History. Compare versions when a change affects eligibility, locations, enrollment, outcome measures, or study status. The history can show whether the record changed after you received an advertisement or completed a call.

A recent date means the responsible party submitted or updated information. It does not guarantee that every phone number or open slot reflects today’s local operations. Confirm current details with the site.

What to include in your first message

Share only the information needed for the first step. Ask the coordinator to identify the study, local site, purpose of the call, and secure method used for medical information. Keep diagnoses, records, identity documents, and insurance details out of an unsolicited reply.

Use this opening: “I am asking about NCT________ at the ________ location. Please confirm the site name, whether this location is screening, the expected first step, and the secure channel used for eligibility information.”

If the answer introduces a different study, site, or vendor, repeat the verification process. A vendor can be legitimate. Require a clear relationship among the vendor, sponsor, and research site.

Handle studies without an NCT number carefully

The absence of an NCT number does not establish fraud. Some studies are not required to register on ClinicalTrials.gov, and some records use another national or international registry. Ask where the study is registered, which IRB or research ethics committee reviewed it, who sponsors it, and which institution conducts it.

Pause when the contact cannot provide a protocol or study identifier, site identity, investigator or research office, consent process, or participant-rights contact. Verify the institution through its own public directory. Report suspicious commercial conduct to the relevant platform, institution, and consumer-protection authority.