GSK has approached a number of London agencies, with both roster and non-roster agencies being asked to tender.
The brief comprises digital and DM elements. Much of the initial work will be adapted from US advertising until such time as plans to launch the drug in Europe are given the go-ahead.
GlaxoSmithKline has already made inroads to get the product approved for sale in Europe, though under a different name. Last month, the European medicines regulator agreed to review a proposal for the drug's over- the-counter sale and respond next year.
This summer, Alli became the first weight-loss drug approved by the United States' Food and Drug Administration for sale over the counter. In the first five weeks after its launch, sales were more than £77 million.
GlaxoSmithKline did not return calls.