Eli Lilly vs Novo Nordisk: Who's Winning the Weight Loss Drug War?

Yes. As of the second quarter of 2026, Eli Lilly held 60.9% of the U.S. obesity and diabetes drug market, compared with 38.8% for Novo Nordisk, according to Lilly’s own earnings presentation ^[1]. Lilly got there by committing more than $50 billion to U.S. manufacturing expansion since 2020, running a head-to-head trial showing Zepbound beat Wegovy on weight loss, and building a direct-to-consumer sales channel with cut cash prices ^[2][3][6]. Novo, meanwhile, replaced its CEO and issued multiple profit warnings in 2025 ^[11].

The lead is not total, though. Novo’s Wegovy pill, launched in January 2026, is far outselling Lilly’s obesity pill, Foundayo, in weekly prescriptions ^[4]. And the two companies are now fighting on several fronts at once: parallel pricing deals with the Trump administration, FDA warning letters over a 2024 Oprah Winfrey TV special, a Novo false-advertising lawsuit against Lilly, and Lilly’s own lawsuits against compounding pharmacies and telehealth sellers ^{[6][7][9][11][14]}.

How big is Lilly’s lead in the GLP-1 market?

Lilly’s 60.9% share of the U.S. obesity and diabetes drug market in Q2 2026 compares with 38.8% for Novo Nordisk, per Lilly’s earnings presentation ^[1]. Independent data points the same way. IQVIA prescription data cited by Citi in September 2026 showed Lilly’s tirzepatide holding nearly 57% of the total GLP-1 market, up from about 49.5% a year earlier, while Novo’s semaglutide stayed roughly flat at about 37% ^[4]. In the obesity market alone, the split was roughly 60% Lilly to 40% Novo as of August 2026, with Zepbound the most-prescribed drug ^[4].

Novo was first to market with the Wegovy injection but later lost the lead to Zepbound, which entered the market roughly three years before August 2026 ^[1][11]. The money followed the prescriptions:

Lilly product	Q2 2026 result
Total company revenue	$22.97 billion, up 48%, vs. $20.73 billion expected [1][17]
Mounjaro (worldwide)	$9.94 billion, up 91%; $4.8 billion in the U.S. [1][17]
Mounjaro (outside U.S.)	Up 172% [1][17]
Zepbound	$4.93 billion, up 46% [1][17]
Foundayo	$98 million, its first quarter of sales [1][5][17]
2026 revenue guidance	Raised to $85–$87 billion, from $82–$85 billion [1][17]

How did Lilly overtake the company that got there first?

Three things stand out. First, manufacturing. On February 26, 2025, Lilly announced that its U.S. capital expansion commitments since 2020 exceeded $50 billion, which the company called the largest pharmaceutical manufacturing investment in U.S. history ^[2]. CEO David Ricks framed the build-out as “our commitment to stay ahead of anticipated demand” for FDA-approved medicines ^[2]. Lilly reaffirmed the more-than-$50-billion U.S. manufacturing investment in its November 2025 agreement with the U.S. government ^[6].

Second, a head-to-head trial. Lilly ran SURMOUNT-5, pitting Zepbound directly against Wegovy, and used the results in national advertising (more on both the trial and the resulting lawsuit below) ^[3][11].

Third, direct-to-patient pricing. Through its LillyDirect self-pay channel, Lilly was already offering Zepbound at a discount to cash-paying patients before November 2025 ^[6][7]. In August 2024, Lilly cut the list price of the Zepbound starter dose from over $1,000 to $399 a month, with the second dose at $549, while raising the price under its patient assistance program from $550 to $650, according to Sen. Bernie Sanders, who called the cut “a modest step forward” ^[16]. Sanders also noted at the time that Mounjaro cost $1,069 a month in the United States, versus $485 in the United Kingdom and $94 in Japan ^[16].

Novo’s own troubles helped. The Danish company replaced its CEO and issued multiple profit warnings in 2025 ^[11].

What did the head-to-head trial actually show?

SURMOUNT-5 was a 72-week, randomized, open-label Phase 3b trial that enrolled 751 adults with obesity, or overweight plus a weight-related condition, in the U.S. and Puerto Rico. None had diabetes. Participants received the maximum tolerated dose of Zepbound (10 mg or 15 mg) or Wegovy (1.7 mg or 2.4 mg) ^[3].

Endpoint at 72 weeks	Zepbound	Wegovy
Average weight loss	20.2%	13.7% [3]
Average pounds lost	50.3 lb (22.8 kg)	33.1 lb (15.0 kg) [3]
Achieved at least 15% weight loss	64.6%	40.1% [3]
Achieved at least 20% weight loss	48.4%	27.3% [3]
Achieved at least 25% weight loss	31.6%	16.1% [3]

Lilly reported the 20.2% figure as 47% greater relative weight loss than Wegovy ^[3]. Discontinuation due to adverse events was 6.1% on Zepbound versus 8.0% on Wegovy, though the trial was not powered to compare safety between the two drugs ^[3]. The full results were published in The New England Journal of Medicine and presented at the European Congress on Obesity on May 11, 2025; the trial was completed in 2024 ^[3][11].

Where is Novo winning: the pill race?

Novo launched the Wegovy pill in January 2026; the FDA approved Lilly’s Foundayo (orforglipron) on April 1, 2026 ^[4][5][11]. In their first quarters on the market, the gap was wide: the Wegovy pill brought in $355 million, and $496 million in its second quarter, while Foundayo took in $98 million, including $67 million in the U.S. ^[4][5]. Analyst estimates compiled by FactSet had forecast nearly $103 million for Foundayo, and BMO Capital Markets called the result about 3% below consensus ^[1][5].

Oral GLP-1 measure	Wegovy pill	Foundayo
Weekly prescriptions, week of September 11, 2026	~183,000	47,500 [4]
First-quarter sales	$355 million	$98 million [5]
Second-quarter sales	$496 million	— [5]
Share of new oral obesity prescriptions	—	21.5% (Jefferies, August 28, 2026) [4]

Both drugs hit record prescription levels in the week of September 11, 2026, per IQVIA data cited by Citi, which also cautioned that IQVIA may be missing some Foundayo prescriptions made through telehealth channels ^[4]. Ricks has argued the oral market is “expansionary, it’s not cannibalizing Zepbound” ^[1].

Why did Foundayo start slower than the Wegovy pill?

Analysts and company executives point to a few reasons. Novo is leveraging its first-mover advantage and the familiar Wegovy brand ^[4]. Lilly secured commercial access across the three major pharmacy benefit managers only in June 2026, and began broad direct-to-consumer marketing after that ^[4]. BMO wrote that patients “prioritize efficacy over convenience” in favor of oral Wegovy ^[5].

Lilly’s pitch for Foundayo is convenience of a different kind: orforglipron is a once-daily small molecule (non-peptide) pill that can be taken any time of day without restrictions on food and water intake, and Lilly licensed it from Chugai in 2018 ^[6]. Lilly has marketed that freedom from fasting and water requirements as an edge ^[4].

The company says momentum is building. On August 5, 2026, Ricks said Foundayo prescriptions and consumer awareness had doubled in a month, and that about a quarter of new patients on oral obesity medications were starting on Foundayo ^[1]. Ilya Yuffa, president of Lilly USA, said the company is “starting to see an inflection point on Foundayo now” ^[4]. The Medicare GLP-1 Bridge program, live July 1, 2026, covers Foundayo at a $50 monthly copay ^[4].

What did Lilly agree to in the Trump administration deal?

On November 6, 2025, Lilly announced an agreement with the U.S. government to expand access to its obesity medicines ^[6]. Starting as early as April 1, 2026, Medicare beneficiaries would pay no more than $50 a month for Zepbound, in a multi-dose pen, and for orforglipron if approved; states could extend access through Medicaid ^[6]. On LillyDirect’s self-pay channel, the Zepbound multi-dose pen was set at $299 for the lowest dose, with higher doses up to $449 — a $50 cut from prior direct prices — and orforglipron was set at $149 for the lowest dose, up to $399 ^[6][7]. The agreement does not include pricing obligations in the commercial channel ^[6]. In return, Lilly said it would receive three years of tariff relief and would not be subject to future pricing mandates ^[6]. Ricks called the deal “a pivotal moment in U.S. health care policy and a defining milestone for Lilly” ^[6][7]. Novo Nordisk announced a parallel deal the same day ^[7].

The government-side details: Lilly and Novo agreed to cut the price Medicare pays for GLP-1s to $245 a month, and to extend $245 pricing for non-starting doses to all 50 Medicaid programs, with states required to opt in ^[7]. Certain Medicare patients pay a $50 monthly copay for all approved uses of injectable and oral GLP-1s ^[7]. The TrumpRx.gov website, launching January 2026, lists injection starting doses at $350, trending down to $245 over two years, and pill starting doses at $149 ^[7]. Medicare’s new obesity coverage runs through a Part D pilot; roughly 10% of about 66 million Medicare beneficiaries are eligible, in three cohorts: BMI over 27 with prediabetes or cardiovascular disease; BMI over 30 with uncontrolled hypertension, kidney disease or heart failure; and BMI over 35 ^[7]. List prices before insurance run roughly $1,000 to $1,350 a month ^[7]. The Medicare obesity coverage launched in early July 2026, and Ricks said the rollout is “off to a strong start” ^[1].

The tariff side of the bargain came into focus on April 2, 2026, when a presidential proclamation under section 232 imposed a 100% ad valorem duty on imported patented pharmaceuticals and ingredients, a 20% rate for companies with Commerce-approved onshoring plans (rising to 100% after four years), and zero tariffs for companies with executed or in-negotiation most-favored-nation pricing and onshoring agreements. Generics and biosimilars are not covered ^[8]. Lilly’s own November 2025 announcement is what promised the company three years of tariff relief ^[6].

What was the FDA warning letter to Lilly about?

The FDA sent Lilly a warning letter dated September 9, 2025, addressed to CEO David Ricks, about Zepbound and Mounjaro ^[9]. Its subject was a 42-minute direct-to-consumer video, “An Oprah Special: Shame, Blame, and the Weight Loss Revolution,” which aired on ABC on March 18, 2024, and appeared on Hulu on March 19, 2024 ^[9][10]. The special featured two paid Lilly consultants, Dr. W. Scott Butsch and Dr. Amanda Velazquez, and Lilly group vice president Rhonda Pacheco ^[9].

The FDA determined the video was false or misleading, misbranded both drugs, and was not submitted to the FDA at the time of dissemination ^[9]. The agency said the video omitted the MEN 2 contraindication, minimized the boxed warning for thyroid C-cell tumors, and left out risks including severe gastrointestinal disease, kidney injury, hypersensitivity reactions, hypoglycemia, suicidal ideation and diabetic retinopathy complications ^[9][10]. When Oprah asked about “serious health effects down the road,” Velazquez said on air that there had been “a lot of hype” around pancreatitis, gallbladder complications and thyroid cancer, and that “the risk is less than 1%” — statements the FDA said “misleadingly minimize the serious risks… including the boxed warning” ^[10].

Lilly received three letters in total for GLP-1 promotions; Novo received one over the same special ^[10]. The FDA demanded the companies cease misleading promotion, respond within 15 days, and submit a plan for corrective communications ^[10].

Why is Novo Nordisk suing Eli Lilly?

Novo sued Lilly on July 21, 2026, in U.S. District Court in New Jersey, alleging violations of the Lanham Act and state false advertising and unfair competition laws through nationwide Zepbound and Mounjaro ad campaigns ^[11][12]. Novo alleges the ads compare the highest approved doses of Lilly’s medicines against lower doses of Wegovy and Ozempic while omitting Novo’s newer, higher-dose version ^[11][12]. Novo’s complaint calls the ads “maliciously and deceptively false,” citing “outdated clinical trials” ^[11].

The trigger: the FDA approved a 7.2 mg dose of Wegovy in March 2026, which showed roughly 19% average weight loss in trials, while Zepbound has shown up to 21% ^[11][12]. Novo sent a cease-and-desist letter in April 2026; Lilly instead added a disclaimer Novo calls inadequate, and the campaign has been served more than 700 million times since the late-April modification ^[11]. Novo’s general counsel, John Kuckelman, said Lilly’s ads compare weight loss of about 50 pounds for Zepbound with about 33 pounds for Wegovy, even though — in Novo’s position — no head-to-head trial has compared the highest approved doses; he said separate highest-dose trials showed about 48 pounds for Zepbound and about 47 for Wegovy ^[11][12].

Lilly’s response: SURMOUNT-5 “remains the only head-to-head, randomized clinical trial” directly comparing the two drugs in weight management, and its advertising is “truthful, it is transparent, and it is grounded in the most direct scientific evidence available” ^[12]. A Lilly spokesperson said Novo is “asking a court to stop Lilly from communicating the results” of that trial ^[11]. Novo is seeking withdrawal of the ads, corrective advertising, preliminary and permanent injunctions, and damages including Lilly’s profits ^[11][12]. Professor Alexandra Roberts of Northeastern University School of Law said damages could be significant but may be limited by the short window since the March 2026 approval of the higher Wegovy dose ^[11].

Why is Lilly suing compounding pharmacies and telehealth companies?

It starts with the shortage. Tirzepatide injection was added to the FDA’s drug shortage list on December 15, 2022, and removed on October 2, 2024 ^[13]. The Outsourcing Facilities Association sued the FDA on October 7, 2024, in the Northern District of Texas, and the decision was remanded to the agency on October 11, 2024 ^[13]. On December 19, 2024, the FDA issued a declaratory order determining the shortage was resolved, revoking and replacing its October 2 decision, based on Lilly data showing supply meeting or exceeding demand ^[13]. The FDA gave compounders an enforcement grace period: state-licensed pharmacists and physicians under section 503A until February 18, 2025, and outsourcing facilities under section 503B until March 19, 2025 ^[13].

Lilly had already sued compounding pharmacies Strive Pharmacy (in the U.S. District Court for the District of Delaware) and Empower Pharmacy (in the District of New Jersey) ^[14]. In April 2025, it filed four more suits in the Northern District of California against telehealth companies Fella Health, Willow Health, Henry Meds and Mochi Health ^[14]. Lilly’s claims: the companies market mass-produced compounded tirzepatide as “personalized,” engage in false advertising, and sell tirzepatide in pill and drop forms that have never been studied or approved by the FDA; Lilly also accused Mochi and Fella of the corporate practice of medicine under California law ^[14].

The Mochi case has been trimmed repeatedly. Judge Jacqueline Scott Corley dismissed the first complaint in 2025 for failure to articulate harm, partially granted a second dismissal motion in April 2026 by axing Lanham Act claims, and on September 8, 2026 dismissed Lanham Act conspiracy claims against Mochi Health and supplier Aequita while allowing Unfair Competition Law corporate-practice-of-medicine conspiracy claims against Aequita Pharmacy and Aequita Corp. to proceed ^[19]. A Lilly spokesperson said the decision confirms Lilly can proceed on all three of its claims and cited “more than a dozen permanent injunctions” Lilly has obtained against telehealth companies, medspas and mass compounders ^[19].

Compounders fought back, and lost. Strive Specialties sued Lilly and Novo in January 2026 in the Western District of Texas, alleging exclusive telehealth deals blocked doctors from prescribing compounded GLP-1s ^[15]. On August 6, 2026, Judge Micaela Alvarez dismissed the case, finding no plausible product market because compounded GLP-1s are available only when a physician determines a branded drug cannot meet a patient’s specific needs ^[15]. “Antitrust laws protect competition — not individual competitors,” she wrote ^[15]. Lilly called it a “meritless claim” and said the ruling “confirms that companies mass compounding tirzepatide are violating the law” ^[15].

Has the rivalry actually lowered prices?

By Lilly’s own reporting, yes — at the cost of realized revenue per unit. In Q2 2026, worldwide realized prices fell 13% while volume rose 60% ^[17]. In the U.S., realized prices fell 3% (about 9% excluding adjustments to rebate and discount estimates) while volume rose 37% ^[17]. Outside the U.S., prices fell 36% — largely from Mounjaro’s addition to China’s National Reimbursement Drug List — while volume rose 113% ^[1][17]. Zepbound’s U.S. revenue still grew 44% despite previously announced reductions in cash-pay prices ^[17].

What does all this mean if you take one of these drugs?

Two practical takeaways. First, prices differ a lot depending on the channel — self-pay through LillyDirect, Medicare, Medicaid, or TrumpRx — and they have changed repeatedly since 2024, so a price you saw last year may not be the price today ^[6][7][16]. Second, the comparative weight-loss claims in TV ads for Zepbound and Wegovy are the subject of active litigation, and the two companies disagree sharply about what the evidence shows ^[11][12].

Sources

1. CNBC. Eli Lilly easily tops quarterly estimates, raises outlook as Zepbound and Mounjaro sales surge. August 5, 2026.
2. PR Newswire. Lilly plans to more than double U.S. manufacturing investment since 2020 exceeding $50 billion. February 26, 2025.
3. PR Newswire. Zepbound (tirzepatide) showed superior weight loss over Wegovy (semaglutide) in complete SURMOUNT-5 results published in The New England Journal of Medicine. May 11, 2025.
4. Fierce Pharma. The Oral GLP-1 Tracker: Novo’s Wegovy pill, Lilly’s Foundayo continue prescription climb. September 11, 2026.
5. BioSpace. Lilly’s $23B Q2 soars over expectations but Foundayo lags Novo’s rival oral GLP-1. August 5, 2026.
6. PR Newswire. Lilly and U.S. government agree to expand access to obesity medicines to millions of Americans. November 6, 2025.
7. CNBC. Trump announces deals with Eli Lilly, Novo Nordisk to slash weight loss drug prices, offer some Medicare coverage. November 6, 2025.
8. The White House. Adjusting Imports of Pharmaceuticals and Pharmaceutical Ingredients into the United States. April 2, 2026.
9. US Food and Drug Administration. Warning letter: Eli Lilly and Company. September 9, 2025.
10. BioSpace. FDA’s Ad Crackdown Targets Novo, Lilly’s Oprah Special on GLP-1s. September 17, 2025.
11. Reuters. Novo sues Lilly, claiming misleading ads in weight-loss drug battle. July 21, 2026.
12. Healthcare Dive. Novo sues Lilly, alleging ‘misleading’ advertising of obesity drugs.
13. US Food and Drug Administration. Declaratory order: Resolution of shortages of tirzepatide injection products (Mounjaro and Zepbound). December 19, 2024.
14. Holland & Knight. Eli Lilly Strikes Back Against Pharmacy Compounders and Telehealth Platforms. June 13, 2025.
15. Reuters. Lilly, Novo defeat antitrust lawsuit over GLP-1 drug market. August 6, 2026.
16. Senator Bernie Sanders. Sanders Statement on Eli Lilly’s Decision to Lower the Starter Price of Blockbuster Weight-Loss Drug Zepbound. August 27, 2024.
17. PR Newswire. Lilly reports second-quarter 2026 financial results, raises full-year guidance, and highlights continued growth and pipeline progress.
18. The Lancet Diabetes & Endocrinology. Once-weekly semaglutide 7.2 mg in adults with obesity (STEP UP): a randomised, controlled, phase 3b trial.
19. Courthouse News Service. Eli Lilly lawsuit against weight-loss drug seller gets another shave.
20. Law360. Calif. Judge Hands Eli Lilly Mixed Bag In Compound Drug Suit.