Viking Therapeutics emerges as dark-horse threat to $36.5B obesity drug market

A mid-cap biotech with a promising weight-loss candidate is positioning itself to challenge a duopoly that controls more than 90% of the GLP-1 market.

Viking Therapeutics is emerging as a potential competitor to Eli Lilly and Novo Nordisk in the obesity drug market, offering a weight-loss candidate that early data suggests could rival the blockbuster franchises of the two dominant players. The San Diego-based biotech's lead program targets the same GLP-1 receptor pathway that has made Lilly's Zepbound and Novo's Wegovy two of the best-selling drugs in pharmaceutical history.

"Viking's candidate shows a competitive efficacy and tolerability profile that could allow it to capture meaningful market share in a rapidly expanding category," said Sam Goldstein, a biotech analyst. "The question is whether its data will hold up against next-generation programs from Pfizer and Amgen that are also advancing through the pipeline."

Eli Lilly and Novo Nordisk together generated more than $36.5 billion in combined sales from their tirzepatide and semaglutide franchises in 2025, according to company filings. Lilly's Zepbound and Mounjaro alone accounted for $36.5 billion, or 56% of the Indianapolis drugmaker's $65.2 billion in total revenue last year. Lilly became the first pharmaceutical company to reach a $1 trillion market capitalization, underscoring the scale of the opportunity Viking is trying to tap.

The obesity drug market is projected to grow to more than $100 billion annually by the end of the decade, driven by rising demand for treatments that address the root causes of metabolic disease. Viking's candidate, if approved, would enter a field where two players currently control more than 90% of prescriptions, according to industry data. That concentration creates both an opportunity and a hurdle: the market is large enough to support multiple entrants, but Novo and Lilly are investing heavily in next-generation oral formulations and combination therapies to defend their turf.

Viking's clinical program has drawn attention partly because of its focus on tolerability, a key differentiator in a class of drugs where gastrointestinal side effects often lead patients to discontinue treatment. The company has not yet disclosed full comparative data against competing pipeline programs, leaving investors to gauge its prospects based on early-stage results and the design of its ongoing trials.

Pfizer and Amgen are also advancing weight-loss candidates, adding further competitive pressure to a field that has already reshaped the pharmaceutical industry. Pfizer recently acquired obesity biotech Metsera for close to $10 billion after fending off a competing bid from Novo Nordisk, signaling the intensity of the race to develop next-generation therapies.

For Viking, cash runway remains a critical factor. The company will need to fund late-stage clinical trials and potential manufacturing scale-up without the balance sheet of a large pharmaceutical partner. Biotech companies at Viking's stage typically require several hundred million dollars to bring a drug through Phase 3 trials and regulatory review, a process that can take three to five years.

Viking shares have rallied this year as investors bet on the company's ability to carve out a position in the obesity market. The stock's valuation hinges on whether its candidate can demonstrate a meaningful advantage in efficacy, tolerability, or dosing convenience compared with the entrenched leaders and the pipeline contenders closing in behind them.

This article is for informational purposes only and does not constitute investment advice.