Eli Lilly and Novo Nordisk are racing to expand their footprint in the multi-billion-dollar weight-loss market. Both companies have competing oral GLP-1 drugs and next-generation pipeline candidates, and have recently intensified efforts to crack down on compounding pharmacies and black-market sales channels. Lilly currently holds the sales lead, while Novo Nordisk is trying to regain ground.

The latest earnings reports from the two companies offer a window into their respective strengths and challenges in this evolving market. Lilly posted strong second-quarter results, with revenue nearing $23 billion, up 48% year over year, which the company attributed to the success of Mounjaro and Zepbound. According to a recent Evaluate report, these two tirzepatide treatments alone are projected to be worth up to $70 billion by 2032. However, its oral weight-loss drug Foundayo recorded $98 million in second-quarter sales, below analyst expectations—its sales growth since launching in April has lagged behind Novo Nordisk's oral Wegovy over the same period.

Novo Nordisk's results were mixed. Its oral Wegovy posted first-quarter sales of $354 million, nearly double analyst expectations, but actual sales between April and June still came in below forecasts. Still, cumulative prescriptions for the oral drug have surpassed 5 million since its January launch, and sales momentum remains strong, prompting Novo Nordisk to raise its full-year outlook.

While supply-side strategies will profoundly shape the GLP-1 market landscape, several recent surveys suggest drugmakers also need to watch other factors, including drug affordability, physician prescribing preferences, and patient perceptions of these medications.

Prescribing preferences may favor Lilly

A survey by Spherix Global Insights shows that some prescribers have clear preferences for GLP-1 drugs, and Lilly may benefit. Among 185 respondents—including physicians, nurse practitioners, and physician assistants—80% said they were highly satisfied with Zepbound, compared with 59% for Wegovy injection, 48% for oral Wegovy, and 47% for Foundayo.

Zepbound ranked first on "most significant weight loss," "fastest onset of action," and "most sustainable weight loss." It was also rated the best-tolerated option, but lost points on out-of-pocket costs. Competitors ranked higher than Zepbound on some dimensions: for example, Wegovy scored highest on cardiovascular outcome evidence and accessibility, while oral Wegovy led on affordability.

The high cost of weight loss

Cost poses another potential barrier as drugmakers seek to expand the audience for weight-loss medications. A KFF survey found that 55% of current or former GLP-1 users—all with health insurance—said they found it difficult to afford their GLP-1 prescriptions.

For injectable GLP-1 drugs, out-of-pocket costs with insurance typically range from $25 to $150, depending on coverage. But according to Forbes, many health plans do not cover these drugs when used solely for weight loss. Without insurance, these medications—often taken long-term—average $900 to $1,400 per month out of pocket. The newer oral GLP-1 drugs are cheaper—at least at their listed cash prices. Oral Wegovy and Foundayo both start at around $149 per month for uninsured cash-paying patients, while copays with insurance can be as low as $25.

High drug prices have driven many patients to compounded versions, which are often cheaper, but that can carry safety risks. More commonly, patients simply stop taking the medication. Spherix survey respondents estimated that 74% of patients who discontinue GLP-1 treatment do so for cost reasons.

Federal efforts have emerged to make these drugs more affordable. The government website TrumpRx provides patients with links to discounted GLP-1 drugs. Additionally, according to IQVIA analysis, research into the long-term health benefits of these drugs is ongoing, which could pave the way for broader insurance coverage.

Overcoming social stigma

Even when patients can afford the medication, some may still be deterred by the stigma surrounding these drugs. A HarrisX–Allison Worldwide study covering more than 6,000 adults in the U.S. and U.K. found that while some view these drugs as a medical advancement, others are judgmental about their use.

The study found that nearly a quarter of U.S. adults reported having used GLP-1s, and another 23% said they would consider using them; but half of respondents viewed these drugs as a "shortcut" for weight loss. Additionally, nearly three-quarters of U.S. respondents believed too many people are using these drugs to lose weight for cosmetic reasons.

Still, the research shows GLP-1s enjoy relatively broad support. About 66% of respondents said using GLP-1s is socially acceptable, and 64% would be willing to disclose their use publicly. GLP-1 users held more positive attitudes than non-users, with 68% of users saying the drugs worked "better than expected." The study also found that social media can shift public perception: 58% of U.S. respondents said seeing online creators talk about using GLP-1s improved their views of these drugs.

For Novo Nordisk and Lilly, winning market share may depend not only on the efficacy of the drugs themselves. Success may also hinge on how patients and physicians perceive these drugs and their affordability.