Losing weight hasn’t quite been the hardest part of modern obesity treatment. Keeping it off is.

That’s exactly the problem Eli Lilly (LLY) seems to have cracked with its weight-loss pill.

In a late-stage trial, patients switching from weekly injections to Lilly’s oral drug were able to maintain their lost weight, perhaps the biggest frustration with GLP-1 drugs.

For many patients, shots work, but not something they’d want to take forever. Cost, convenience, long-term health care risks, and simple fatigue tend to get in the way. Historically, that’s also when the weight creeps back.

However, Lilly’s data points to a different path where, once you’re done losing weight through injections, you could switch to a pill to maintain it. 

If that approach holds up, we’re likely to see a fundamental shift in long-term obesity care.

Eli Lilly’s obesity pill helped patients maintain weight loss after switching off weekly GLP-1 injections.

Photo by Peter Dazeley on Getty Images

Stopping injections usually leads to weight regain

Halting GLP-1 injections typically results in weight regain because the drug’s appetite suppression doesn’t linger for a long time.

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In a major semaglutide study, patients losing nearly 17% of body weight regained approximately two-thirds of it within a year after stopping treatment.

We see a similar trend with tirzepatide, where patients who stopped using the drug regained nealry 14% over the following year. 

That’s because the hunger signals return, metabolism adjusts, and the body resets to its old baseline.

Lilly’s obesity pill changes the long-term equation

The real test for obesity drugs is once the injections stop. 

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Historically, that’s also when the weight creeps back up, and that’s also true for patients who saw encouraging results. 

Eli Lilly’s latest trial points to a completely different outcome, though, and one that might reshape how long-term treatment works.

Key trial details:

  • After 72 weeks on weekly GLP-1 injections, patients who moved to Lilly’s daily pill were tracked for another year.
  • Those on Lilly’s pill outperformed the placebo on weight loss maintenance.
  • Former Wegovy users on the pill regained just 2 pounds, maintaining nearly 95% of their previous weight loss.
  • Patients who moved from Zepbound to the pill regained almost 11 pounds, still preserving around 80% of the weight lost.
  • Lilly has filed for FDA approval, with a potential decision slated for March 2026, backed by a priority review voucher.

Kenneth Custer, president of Lilly Cardiometabolic Health, weighed in on the results, saying it could,

Key players in the weight-loss drug market

  • Eli Lilly has taken center stage with tirzepatide, marketed as Zepbound and Mounjaro, helping patients shed around 20% of body weight in trials.
    In Q3 2025, the drugs contributed to a massive $10.1 billion in sales, more than doubling a year earlier while blowing past Merck’s Keytruda, the top-grossing drug.

    Lilly is also now looking to spread its tentacles with orforglipron, a daily pill controlling up to 60% of a projected $22 billion obesity pill market by 2030.

  • Novo Nordisk virtually built the category with its pioneering Ozempic and Wegovy brands, delivering nearly 15% weight loss while still holding nearly 68% of global GLP-1 volume. 
  • Other drugmakers, including Pfizer and Amgen, are in the race to catch up with pills and next-generation therapies in what’s now a more crowded market.

Obesity drugs are creating a market that pharma hasn’t seen before

The weight-loss drug market continues blowing up, and Mr.Market’s taking notice. 

Wall Street analysts forecast annual sales to jump to $100 billion by 2030, while some forecasts indicate it could surge past $150 billion in the early 2030s, as treatments expand globally.

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That level of expansion is virtually unheard of in the pharmaceutical industry, drawing comparisons to tech-sector booms. 

Eli Lilly’s incredible rise shows exactly why. 

Spearheaded by its powerful obesity and diabetes franchise, it reached a $1 trillion market cap in November 2025, the first healthcare company ever to do so. 

LLY stock is up a whopping 39% year-to-date, and 37% alone in the past six months.

From a financial standpoint, Lilly’s results underscore that the obesity boom is directly translating into bottom-line strength.

In Q3 2025, sales surged 54% year-over-year to $17.6 billion, blowing past market expectations. 

Tirzepatide spearheaded the surge, generating a massive $10.1 billion in quarterly sales, up substantially from $4.4 billion a year earlier. 

Moreover, this also made Lilly’s GLP-1 franchise the top-grossing drug on a global sales basis for the quarter, surpassing Keytruda.

On the back of that expansion, Lilly bumped its full-year 2025 sales outlook to nearly $63 billion, pointing to 30%+ growth.

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