When does the ebook loan period begin after approving an STL for a user in Ebook Central?

When a librarian approves a mediated request for an STL (short-term loan), the loan period does not start until the patron clicks on the ebook link in the email sent for the approval notification or when the patron visits the Title Detail page.
Please note that for approved purchase requests, it is possible for another user to checkout the ebook before the original requester is able to check it out. This would generally only be a possible occurrence for a 1-user or 3-user copy. As soon as a librarian approves a purchase request, the ebook becomes available on the Ebook Central site for any user to check out. The approval notification email is sent to the requester straight away.