This document contains the following information: 

• How to find the date a chemical was added to the PubChem database
• How to find the information associated with the earliest public record, including submitted synonyms and other metadata

A PubChem Compound Summary page represents one standardized chemical structure and is identified by a PubChem Compound ID (CID). PubChem Compound records are updated as new information becomes available. 

A Related Substance record represents information submitted by one data contributor and is identified by a Substance ID (SID). SID dates include the following:  

• Deposit Date: When the SID was received or first entered into PubChem
• Available Date: When the record became publicly accessible
• Modify Date: When the record was last changed
• Hold-Until Date: A release date specified by the contributor, when applicable

How to find when a chemical was added to the PubChem database 

PubChem does not record the exact date and time a record first became publicly visible. You can use the Related Substances records and their associated dates to understand when submitted information became publicly available. Records can include structures, synonyms, registration identifiers, descriptions, URLs, patents, literature links, and other contributor-provided metadata. For more information, please review the PubChem Substance documentation. 

Find the chemical’s compound record 

1. From the PubChem home page, enter the name of the chemical in the search field and click the search icon or select from the list under Compound.  

2. From the results, click the name of the compound or CID number to open the Compound ID record. 

View the Related Substances records 

3. From the compound page, scroll to the Related Substances section and click the All Count number. A list of all Substance ID (SID) records displays. 

Find the information associated with the earliest public record, including submitted synonyms and other metadata 

4. Sort the PubChem Substance records by the oldest Deposit Date. 

5. Review the earliest records to identify the first submitted information associated with the chemical.  

• To view all versions of the Substance record that exist, in the top section click the Version pull-down to change the display and show dates and information for any existing earlier versions of the record.