The chemical probes database is a high-quality manually curated set of compounds with more trustworthy biological activity. Before starting a biological study it is good to check for a curated tool here - the literature is replete with time-wasting bad actors.
clinicaltrials.gov
The US NIH's Clinical Trials database is a powerful tool to find primary data and status updates on investigational molecules. I often search molecule IDs using "other terms".
clinicaltrialsregister.eu
A similar database for clinical trials conducted in the EU
drugbank.com
Drugbank.com is a convenient secondary database to look up drug properties, references, etc. when starting a search on an investigational or clinical molecule.
