SINimilarity shows if a substance is structurally similar to a substance on the SIN List, which in turn indicates similar problematic properties. The aim is to help avoid substituting one problematic chemical with another.

SINimilarity compares a substance with chemicals on the SIN List, a globally used database with chemicals that have been identified by ChemSec as Substances of Very High Concern (SVHC) based on the criteria established by the European Union chemicals regulation REACH. Almost 500 000 chemicals can be investigated by name, CAS number, EC number or structure. For the advanced user, there is also the possibility to search by entering the molecular structure.