Lenders are now required to advertise on at least one price comparison website, and include a prominently displayed link to this on their own site.
The changes are intended to make it easier for borrowers to compare brands and get a clearer understanding of the fees and charges involved, as well as for new entrants to more easily compete with established players.
A price cap on payday loans came into force in January 2015, after a separate investigation by the Financial Conduct Authority.
But industry body the Consumer Finance Association had criticised the cap, saying it had resulted in a 42% fall in loan approvals since 2013, the BBC reports.
