Eli Lilly (LLY) plans to advertise its blockbuster weight loss drug, Zepbound, for the first time next month.

Despite investor and industry recognition of the branded GLP-1 drug, “Zepbound’s unaided awareness … is actually not very high,” CEO David Ricks said in an earnings call Wednesday morning.

The company missed Wall Street expectations on the top and bottom lines, including the drug itself — reporting sales of $1.3 billion for the quarter, compared to the $1.7 billion expected.

Shares of the company fell more than 13% in early trading on Wednesday.

The FDA first approved the drug in November 2023, and sales reached more than $1 billion by the second quarter of this year. To date, Lilly’s total revenue since the drug’s launch, excluding advertising, is $3.2 billion.

“We launched this drug almost a year ago and did not do any advertising. So I think it’s time to introduce the brand so people are aware of it when they talk to their doctor,” Ricks said.

The company had to wait for supply to meet demand, which the FDA determined was the case earlier this month. However, this decision is being reconsidered after the rejection from compounding pharmacies who filled the shortfall in the meantime with unapproved knockoffs of Lilly’s tirzepatide drugs, including the diabetes drug Mounjaro.

Lilly’s new CFO Lucas Montarce said the company has much more confidence in supply going forward. He added that the total addressable market for Zepbound has only reached 5% penetration – so the company needs to do everything it can to raise patient awareness, including through the direct-to-consumer platform LillyDirect.

The decision also comes at a time when Lilly is increasingly taking market share from rival Novo Nordisk (NGOs), which announced the end of his absences on Wednesday.

“If we look at the last 90 days (and) 180 days of US prescription growth, both brands are growing aggressively. We have now overtaken Wegovy in the slimming sector,” Ricks told Yahoo Finance in an interview on Wednesday.

In diabetes, “we don’t quite match Ozempic with Mounjaro, but every week we’re basically eating up market share,” he added.

In weekly prescription data ending Oct. 18, Eli Lilly’s Mounjaro captured 33 percent of the market share, or a year-over-year jump of 79 percent, while Novo’s Ozempic was at 47 percent , or a year-on-year jump of 39%. But the numbers have shifted in Lilly’s favor this year, according to data compiled by JPMorgan analysts.

In February, data for the week ending February 16 showed Mounjaro at 29% of the market compared to Ozempic’s 44%.

Market share data for Zepbound and Wegovy is not available, but average quarterly prescription data shows that Wegovy prescriptions grew 123% year-over-year in October, compared to Zepbound’s 3,281% increase. The data also shows Zepbound prescriptions since launch outpaced all three other drugs (Ozempic, Mounjaro and Wegovy) in the first 12 weeks, but supply constraints have slowed it down.

Update: An earlier version of this article stated that Novo Nordisk was still experiencing shortages. The FDA today declared an end to the Novo shortage.

Anjalee Khemlani is the senior health reporter at Yahoo Finance, covering all things pharma, insurance, care services, digital health, PBMs, and health policies and politics. That includes GLP-1, of course. Follow Anjalee on most social media platforms @AnjKhem.

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