The Biggest Zepbound and Mounjaro Stories of 2025

2025 was the year tirzepatide stopped being a supply story and became a coverage story. Nobody was hunting for pens anymore. Instead the arguments were about who pays, which insurer covers which brand, and whether Medicare would ever get involved.

Here is what actually happened, in order, with sources. This is a news recap. It does not tell you which drug to take or what any of it means for your own care, which is a conversation for a healthcare provider.

Did Medicare finally start covering obesity drugs?

Sort of, and in a roundabout way.

Medicare is barred by law from paying for drugs used for weight loss. But on January 8, 2025, CMS confirmed that Part D plans could cover Zepbound when it is prescribed for obstructive sleep apnea, because sleep apnea is a medically accepted indication rather than weight loss [1]. Zepbound had won that indication three weeks earlier, and it is still the only drug ever approved for the condition.

Then the door swung the other way. On April 4, the administration declined to finalize a Biden-era proposal that would have let Medicare cover obesity drugs outright, citing cost [2].

It reopened in November, on very different terms, as part of the pricing deal described below.

Why did CVS drop Zepbound, and what happened to patients?

This was the commercial shock of the year.

On May 1, 2025, CVS Caremark named Wegovy the preferred obesity drug on its largest commercial formulary template, effective July 1, and excluded Zepbound [3]. Lilly’s shares fell on the news even though the company had just reported first-quarter revenue up 45%.

The practical effect was that hundreds of thousands of people taking one drug were switched to another for contracting reasons rather than clinical ones. Lilly published an open letter in May arguing that switching patients between obesity drugs for rebate reasons is bad medicine. A class action followed in September.

The story has an ending, though it arrived later: in May 2026 CVS Caremark said it would restore Zepbound to the formulary from October 1, 2026, and add Lilly’s new obesity pill alongside it.

How much did Zepbound’s cash price fall in 2025?

Steadily, in steps.

On February 25, Lilly added 7.5 mg and 10 mg single-dose vials to its self-pay lineup and cut prices, listing 2.5 mg at $349 and 5 mg at $499 a month for people who refill on schedule [4][5]. In June it made every approved dose available as a vial. On December 1 it cut single-dose vial prices again, to $299 for 2.5 mg, $399 for 5 mg and $449 for every higher dose when the prescription is refilled within 45 days [6]. Those are still the self-pay prices as of September 2026, with $499 for 7.5 mg and $699 for the top three doses if a refill lapses past 45 days [25].

Two things were driving this. The compounded tirzepatide market was winding down under FDA deadlines, and Lilly wanted those cash-paying patients to land on branded product rather than disappear. And from November, the White House pricing deal put a public number on what Americans should pay.

The delivery side kept expanding too. In March, Teladoc and LifeMD tied up with Lilly’s pharmacy partner to sell the discounted vials [7]. On October 29, Lilly and Walmart announced the first retail pickup option for LillyDirect self-pay vials, with collection at Walmart pharmacies nationwide from mid-November [8]. Lilly said at the time that roughly 35% of new Zepbound prescriptions in the second quarter had been filled through its direct channel.

What ended the compounded tirzepatide market?

Court rulings, mostly.

The FDA had removed tirzepatide from the shortage list in late 2024, which ended the legal basis for most compounding. Compounders sued. In March a federal court declined to block the delisting, and on May 7, 2025, the court sided with the FDA outright [9].

Copies did not vanish overnight. They moved into personalized-dosing arguments, gray-market peptide sellers and overseas suppliers, and Lilly kept suing. But the mass-market compounded tirzepatide business that had existed since 2023 was over as a legal proposition.

Did Zepbound actually beat Wegovy?

In the one randomized trial that compared them, yes.

The complete SURMOUNT-5 results published in the New England Journal of Medicine on May 11, 2025 showed average weight loss of 20.2% on tirzepatide against 13.7% on semaglutide 2.4 mg over 72 weeks [10]. That is a large gap by the standards of head-to-head drug trials.

The counterargument arrived at the end of August, when Novo Nordisk presented its STEER real-world analysis at the European Society of Cardiology congress, reporting that Wegovy was associated with 57% fewer heart attacks, strokes and deaths than tirzepatide in people with obesity and cardiovascular disease. The 57% figure came from a subgroup analyzed only while patients stayed on treatment; across the whole cohort the gap was 29%. Observational data of that kind cannot settle a question the way a randomized trial can, and cardiologists said so, but it gave Novo something to say in a year when it needed one [24].

Lilly’s own heart evidence came on July 31, when SURPASS-CVOT reported that tirzepatide was non-inferior to Trulicity on major adverse cardiovascular events in more than 13,000 adults with type 2 diabetes, with lower all-cause death [11]. Investors had hoped for outright superiority and the shares barely moved. The FDA approved the indication a year later.

What happened with Lilly’s obesity pill?

It worked, and the market was disappointed anyway.

On April 17, orforglipron delivered the first phase 3 win in type 2 diabetes, with A1C reductions of 1.3 to 1.6 percentage points, and Lilly shares jumped 14% [12]. A once-daily pill with no food or water restrictions was a genuinely new thing.

Then on August 7, the first obesity result came in at about 12.4% average weight loss [13]. That is a real number, but it sat below Wegovy’s injection and well below Zepbound’s, and Lilly’s stock dropped double digits on the same morning the company raised its full-year guidance. The chief executive bought $1 million of stock a few days later.

ATTAIN-2 in August completed the obesity package and triggered global filings [14]. In September, ACHIEVE-3 showed the pill beating Novo’s oral semaglutide head-to-head in diabetes. In December, ATTAIN-MAINTAIN showed it could hold weight lost on injections after a switch.

Why did Mounjaro get so much more expensive in Britain?

Because of American politics.

On August 14, 2025, Lilly said it would raise the UK list price of Mounjaro by about 170%, arguing that it would raise European prices so US prices could come down [15]. British pharmacies started stockpiling ahead of the increase and Lilly briefly paused UK shipments at the end of the month.

For US readers the important disambiguation is that in Britain, Mounjaro is the weight-loss brand. Coverage of “the Mounjaro price rise” is about the drug Americans buy as Zepbound, and it does not change US pricing.

Was Mounjaro approved for children?

For type 2 diabetes, yes.

SURPASS-PEDS, presented in September and published in The Lancet, reported an average A1C reduction of 2.2 percentage points in children and adolescents aged 10 to 17 with type 2 diabetes [16][17]. The FDA extended the Mounjaro label to children aged 10 and older on December 19, 2025 [18].

That approval covers diabetes. Pediatric use for weight management remains off-label, and the growth in off-label GLP-1 prescribing to children became its own story in 2026.

What did the White House pricing deal actually do?

On November 6, 2025, Lilly and Novo Nordisk both agreed most-favored-nation pricing arrangements with the administration [19]. For tirzepatide the headline terms set Medicare pricing around $245 a month with a $50 patient copay, opened Medicare coverage of obesity treatment for the first time, and added the drugs to a government-run discount site.

The deal also came with tariff relief and priority review vouchers, which is how Lilly’s obesity pill later reached the market faster than a normal review would have allowed.

Fifteen days later, on November 21, Lilly became the first drugmaker in history valued at a trillion dollars [20]. Three weeks before that, tirzepatide had passed Merck’s Keytruda to become the best-selling medicine in the world, at $10.1 billion in third-quarter sales against Keytruda’s $8.1 billion. That record is held by the molecule across both brands together, Mounjaro and Zepbound, not by Zepbound alone [21].

What is coming next, based on how 2025 ended?

December gave three previews.

Retatrutide, Lilly’s triple agonist, posted its first phase 3 win on December 11 with weight loss of up to 28.7% plus relief from knee osteoarthritis pain [22]. It is the biggest weight-loss number any drug has produced in a phase 3 trial, and it also came with discontinuation rates analysts flagged.

Lilly’s obesity pill was filed and heading for a fast review under the new voucher program. It was approved on April 1, 2026.

And the company spent 2025 announcing more than $40 billion of new factories, from a $27 billion four-plant US program in February [23] through sites in Texas, Virginia, the Netherlands, Alabama and India. The company that spent 2022 and 2023 apologizing for shortages has spent every year since building so it never has to again.

Sources

1. Medicare can now cover Eli Lilly’s Zepbound for sleep apnea, CMS says — CNBC, January 8, 2025
2. Trump drops Biden’s proposal for Medicare to cover obesity drugs — CNBC, April 4, 2025
3. Novo strikes deal giving Wegovy preferred access on CVS Caremark formulary — Fierce Pharma, May 1, 2025
4. Lilly launches additional Zepbound vial doses and offers new savings for self-pay patients — PR Newswire / Eli Lilly, February 25, 2025
5. Lilly launches higher-dose vials of weight-loss drug — Reuters, February 25, 2025
6. Eli Lilly cuts cash prices of Zepbound weight loss drug vials — CNBC, December 1, 2025
7. Telehealth firms Teladoc and LifeMD tie up with Eli Lilly’s pharmacy partner — Reuters, March 6, 2025
8. LillyDirect and Walmart Pharmacy launch first retail pick-up option for Zepbound — Eli Lilly, October 29, 2025
9. Compounders lose legal battle with FDA over removal of Eli Lilly’s weight loss drug from a shortage list — STAT, May 7, 2025
10. Complete SURMOUNT-5 results published in the New England Journal of Medicine — PR Newswire / Eli Lilly, May 11, 2025
11. Lilly’s Mounjaro demonstrated cardiovascular protection in a landmark head-to-head trial — PR Newswire / Eli Lilly, July 31, 2025
12. Lilly’s oral GLP-1 orforglipron demonstrated statistically significant efficacy in a successful Phase 3 trial — PR Newswire / Eli Lilly, April 17, 2025
13. Lilly’s oral GLP-1 orforglipron delivers weight loss of up to an average of 27.3 lbs — PR Newswire / Eli Lilly, August 7, 2025
14. Lilly’s oral GLP-1 orforglipron is successful in a third Phase 3 trial — PR Newswire / Eli Lilly, August 26, 2025
15. Lilly to hike UK price of Mounjaro weight-loss drug by 170% — Reuters, August 14, 2025
16. Lilly’s Mounjaro reduced A1C by an average of 2.2% in a Phase 3 trial of children and adolescents — PR Newswire / Eli Lilly, September 17, 2025
17. Efficacy and safety of tirzepatide in children and adolescents with type 2 diabetes (SURPASS-PEDS) — The Lancet, September 17, 2025
18. Drugs@FDA record for MOUNJARO, NDA 215866, supplement 39 — FDA, approval dated December 19, 2025
19. Lilly and U.S. government agree to expand access to obesity medicines — PR Newswire / Eli Lilly, November 6, 2025
20. Eli Lilly hits $1 trillion market value, a first for a health care company — CNBC, November 21, 2025
21. Eli Lilly’s weight loss and diabetes drug tops Keytruda as world’s best-selling medicine — STAT, October 30, 2025
22. Lilly’s triple agonist retatrutide delivered weight loss of up to an average of 71.2 lbs — PR Newswire / Eli Lilly, December 11, 2025
23. Eli Lilly plans at least $27 billion in new U.S. manufacturing investments — CNBC, February 26, 2025
24. Novo Nordisk’s Wegovy cuts risk of heart attack, stroke or death by 57% compared to tirzepatide in real-world study (STEER) — PR Newswire / Novo Nordisk, August 31, 2025
25. Zepbound coverage, affordability and savings — Self Pay Journey Program prices — Eli Lilly, accessed September 14, 2026