The GLP-1 drug category keeps expanding well beyond its original territory. What started as a diabetes and weight-loss treatment has grown to include conditions like obstructive sleep apnea and metabolic dysfunction-associated steatohepatitis, opening up an increasingly large pool of patients—and investor interest along with it.
Eli Lilly currently sits atop this market, but it isn’t without challengers. Viking Therapeutics, a much smaller biotech, has emerged as one of the more closely watched contenders with its own GLP-1 pipeline. The question for investors: does Viking have what it takes to carve out real market share, or does Eli Lilly’s scale make it the safer bet?
Inside Eli Lilly’s Growth Engine
At the center of Eli Lilly’s success is tirzepatide, a drug that mimics both the GLP-1 and GIP hormones and has already secured approval for diabetes, weight loss, and sleep apnea treatment. It remains the single biggest driver of the company’s growth and the top-selling drug in its category.
The numbers back this up. Second-quarter revenue jumped 48% year over year to $23 billion. Mounjaro, tirzepatide’s diabetes-focused brand, saw sales climb 91% to $9.9 billion, while Zepbound—the weight-management version—generated $4.9 billion, a 46% increase from the prior year.
Trading around $1,186 per share with a market capitalization of $1.1 trillion, Eli Lilly isn’t resting on tirzepatide alone. The company also markets Foundayo, an oral GLP-1 option that’s bringing new patients into the fold. Revenue contributions from Foundayo remain modest for now, but that could change meaningfully as it expands into diabetes, sleep apnea, and other approved uses.
Looking further out, Eli Lilly’s pipeline includes retatrutide, a candidate that delivered impressive phase 3 results in both diabetes and weight-loss trials. The company intends to file for approval in the first quarter of 2027. Combined with its existing product lineup and pipeline strength across other therapeutic areas, Eli Lilly appears well-positioned to hold its market lead for some time.
What Viking Therapeutics Brings to the Table
Viking Therapeutics operates in a completely different stage of development—it’s a clinical-stage company without an approved product on the market yet. Its lead candidate, VK2735, shares tirzepatide’s dual GLP-1/GIP mechanism and is currently in phase 3 trials in subcutaneous form, with an oral version expected to enter late-stage testing by year-end.
Trading around $34 per share and carrying a $4.0 billion market cap, Viking’s subcutaneous formulation has already turned heads. In phase 2 testing, it produced average weight loss of up to 14.7% over just 13 weeks, and notably, the weight loss hadn’t leveled off by the trial’s end.
For context, tirzepatide achieved 20.2% average weight loss over a much longer 72-week phase 3 trial—a reminder that cross-trial comparisons should be taken with caution given the different timeframes involved. Still, it raises the possibility that VK2735 could ultimately rival or even surpass tirzepatide’s effectiveness once longer-term data comes in. The oral version has also shown encouraging phase 2 results, though some patients discontinued treatment due to side effects—a detail worth monitoring as trials progress.
Weighing the Two Options
On pure fundamentals, this isn’t a close call. Eli Lilly has an established, diversified portfolio generating billions in reliable revenue and profit. Viking, by contrast, has zero approved products, zero revenue, and no profitability in sight for the foreseeable future.
That said, Viking’s risk profile cuts both ways. Strong phase 3 data could send its stock sharply higher—potentially doubling or more over the next couple of years—as the company stakes out a position in a rapidly expanding market. The flip side is equally real: disappointing trial results could send shares tumbling just as quickly.
Given that asymmetry, Eli Lilly looks like the more prudent choice for most investors. It offers substantial exposure to the ongoing GLP-1 boom through a proven, diversified business, without the binary risk that comes with betting on a single clinical-stage company’s trial outcomes.
