PROSPERO

PROSPERO is an international database containing protocols of systematic reviews with a health-related outcome. The database aims to reduce duplication of systematic reviews and minimise reporting bias by enabling others to compare what was pre-specified and what was reported.

Find more information about PROSPERO here. 

ClinicalTrials.gov

ClinicalTrials.gov is a database of clinical studies conducted around the world. It includes both interventional and observational studies and contains more than 280,000 research studies from 204 countries.

Find more information about ClinicalTrials.gov here.

AllTrials

AllTrials calls for all past and present clinical trials to be registered and their full methods and summary results reported. AllTrials is an international initiative of Ben Goldacre, BMJ, Centre for Evidence-based Medicine, Cochrane Collaboration, James Lind Initiative, PLOS and Sense About Science and is being led in the US by Sense About Science USA, Dartmouth's Geisel School of Medicine and the Dartmouth Institute for Health Policy & Clinical Practice.

Find more information about AllTrials here.