The most reliable method for determining the peer review status of a journal is to select the peer review limiter in a database (where available) and perform your searches with it active.
Peer Review Limiters
Most academic databases now come standard with a peer reviewed journals limiting option embedded somewhere on their search engine:
For EBSCO databases, the limiter will appear somewhere in the Limit your results field in Advanced Search:
Academic Search Complete (top left of Limit your results)
CINAHL Complete (near top of right column, Limit your results)
Searching with Peer Review Limiters
To perform a search using the Peer Review limiter (in EBSCO databases):
1) Locate and select the Peer Review limiter check box
2) Enter your terms in the search box
3) Click the Search button to proceed
How It Works
When active, the Peer Reviewed limiter searches the Publication Type field associated with a record for indications of Academic Journal status.
Academic (aka, Scholarly) Journals, by definition, filter their content using a peer review selection process.
So searching with the filter active automatically culls non-scholarly (non-peer reviewed) sources from your search results.