The US Food and Drug Administration confirmed Thursday that Eli Lilly (LLY) has increased production of its blockbuster weight-loss drug Zepbound and type 2 diabetes drug Mounjaro, implying the company can now supply enough doses to meet current demand.

The metrics used to determine the current demand is not specified by the FDA — and the drug shortages website provides an important caveat: "Even when a medication is available, patients may not always be able to immediately fill their prescription at a particular pharmacy," the FDA said on its site addressing the Mounjaro and Zepbound listing.

Eli Lilly first notified the agency in August that its drugs were no longer in shortage, resulting in the initial removal of both drugs from the agency's drug shortage list. The FDA then verified through its own assessment, which prompted the notification Thursday.

The move is important for two key reasons: It gives Lilly an edge over competitor Novo Nordisk (NVO), which still has doses in shortage, and it starts a countdown clock for compounding pharmacies to cease production of copycats of Lilly's drugs, known by their formula name tirzepatide.

Novo still has some doses of its type 2 diabetes drug Ozempic and weight loss drug Wegovy on the FDA's drug shortage list. And it has been losing market share, ever so slightly, to Lilly in the past couple of weeks, despite being the first to market for both products.

Jefferies analysts noted a shift in the weight loss category, with sales of Lilly's Zepbound increasing by 1.1% to 43.4% of the market for total prescriptions filled in the week of Sept. 27, compared to 42.3% the week before. Wegovy, meanwhile, is clearly losing ground, with a 1.2% loss in the same timeframe, moving from 56.9% of the market's total prescriptions to 55.7% in a week's time. Wegovy's starter doses, 0.25 milligrams, are seeing the heaviest loss in market share, down 37% week over week, according to Jefferies research.

The second big concern is for compounding pharmacies, which have been supplying copycats to medispas, clinics, and online health platforms. The compounders have taken advantage of the outsized demand in the market, knowing that — as both brand manufacturers have admitted — there will be more demand than supply for years.

The drugs' placement on the FDA's shortage list allowed compounders free rein to produce the copycats. But that is now coming to a halt. The FDA said these entities have about 60 days to cease mass production, though they can still produce small amounts.