ClinicalTrials.gov
NIH clinical trial registry. 530,000+ studies from 230 countries. Free. The primary public record of what drugs and treatments are actually being tested — and what the results show.
What should journalists know about ClinicalTrials.gov?
ClinicalTrials.gov is the public ledger of medical research. When a pharmaceutical company announces a promising drug, the trial should be registered here — with its protocol, endpoints, enrollment targets, and (eventually) results. When the company later announces only the favorable findings, ClinicalTrials.gov has the original protocol showing what they actually set out to measure. This gap between registered endpoints and reported results is one of the most important stories in health journalism. The database holds over 530,000 studies from 230 countries, with 2 million unique monthly visitors. It was launched in 2000, and the FDAAA (2007) and Final Rule (2017) strengthened requirements for registration and results reporting — though compliance remains imperfect, which is itself a story. NLM completed a major modernization in 2024-2025, rebuilding the platform from the ground up. The new interface is a significant improvement: cleaner design, better search, and a modernized Protocol Registration System (PRS) that now supports results entry and study document uploads. For journalists, the most valuable features are: trial status tracking (see whether a study is recruiting, completed, or terminated — and why), results reporting (companies are required to post summary results within one year of completion, though many do not), outcome measures (compare what was originally planned against what was reported), and sponsor/collaborator information (follow the money). The API provides programmatic access for monitoring specific companies or therapeutic areas at scale. Critical limitation: ClinicalTrials.gov is a registry, not a quality assessment. Registration does not mean a trial is well-designed, and posted results are sponsor-submitted summaries, not independent analysis. The database tells you what was done and what was found; evaluating whether the methodology was sound is your job.
Verifying pharmaceutical company claims about drug trials. Tracking whether announced trials actually completed and reported results. Comparing registered primary endpoints against published results (detecting outcome switching). Monitoring which companies are running trials for specific diseases or treatments. Finding trial locations and principal investigators for source development. Investigating compliance — which sponsors fail to report results on time.
Evaluating trial quality or methodology (registration does not equal rigor). Getting full published results (ClinicalTrials.gov has summary results; full papers are in PubMed/journals). Tracking preclinical or animal studies (only human clinical trials are registered). Real-time drug safety alerts (check FDA MedWatch for adverse event reports). Understanding what results mean clinically — the database has numbers, not interpretation.
Security & Privacy
Data is scrambled while being sent to their servers
Data is scrambled when stored on their servers
Where servers are located — affects which governments can request your data
Privacy policy summary
US government service. No account required for searching. If you create an account (for saving searches or receiving alerts), NIH collects your email under federal privacy practices. No advertising, no data sales, no third-party tracking. All trial data is public record. Standard government web analytics apply.
How to protect yourself:
No account needed for searching — use without logging in for maximum privacy. For ongoing coverage of a therapeutic area or company, set up email alerts for new registrations matching your criteria. Use the API for systematic monitoring of trial status changes. Cross-reference ClinicalTrials.gov entries with PubMed to find published results that may contain more detail than the registry summaries. Check the 'History of Changes' tab on any study to see protocol amendments — changes to primary endpoints after enrollment begins can indicate outcome switching. Use the 'Results' tab to see summary data even before full papers are published.
US government service operated by NIH/NLM with no advertising, no data sales, and no third-party tracking. No account required for searching. All data is public record. Minimal data collection. The 'strong' rating reflects institutional credibility, federal security standards, absence of commercial incentives, and the fact that using this service exposes no meaningful personal data.
Who Owns This
Known issues
Compliance with results reporting requirements is imperfect. Studies have found that 30-50% of applicable trials fail to report results within the required one-year window. Penalties for non-compliance (up to $10,000/day per FDAAA) have rarely been enforced by NIH or FDA — this is a known accountability gap. Not all trials are required to register: Phase 1 trials, many device studies, and trials of unapproved products have narrower requirements. Sponsor-submitted results are not independently verified by NLM — they are posted as received, with basic quality checks but no methodological review. The modernized platform (2024-2025) is a major improvement but some users report search behavior differences from the legacy system. International trial registries (EU Clinical Trials Register, ISRCTN, WHO ICTRP) may contain trials not registered on ClinicalTrials.gov, especially for non-US sponsors.
Pricing
Free
This is an editorial assessment based on publicly available information as of 2026-04-11, using our published methodology. Independent security review is pending. Security posture can change at any time. This is not a guarantee of safety.
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