Look up the journal in Ulrich's by either title of ISSN. ISSN is a unique number assigned to every journal and magazine, so searching by ISSN will get you to the correct journal more quickly. You can usually find this number listed in the database where you found the article you are investigating.
Once you find the journal, look at the basic description section. There is a row labeled "Refereed", which is the term that Ulrich's uses for peer-reviewed. If this line says "yes", then the journal is peer-reviewed.
![Screen shot from Ulrich's, showing where to find refereed information](//libapps.s3.amazonaws.com/accounts/143419/images/ulrichsexample.png)