GLP-1 drugs: semaglutide, tirzepatide and what comes next

GLP-1 stands for glucagon-like peptide-1. It is a short hormone made by cells lining the lower small intestine and colon, released within minutes of eating. Its natural job is to coordinate a meal: it tells the pancreas to release insulin only when blood sugar is high, tells it to hold back glucagon (a hormone that raises blood sugar), slows the emptying of the stomach, and signals fullness to the brain. Hormones with this meal-triggered action are called incretins.

The natural hormone is a poor medicine because it is destroyed fast. An enzyme called DPP-4 inactivates it within minutes, even before it leaves the gut (Holst, Physiological Reviews, 2007). Every GLP-1 drug is therefore a chemically altered copy that resists that enzyme and, in modern versions, binds to the blood protein albumin so that a single weekly injection lasts.

GIP, glucose-dependent insulinotropic polypeptide, is the second major incretin. Tirzepatide, the active ingredient in Mounjaro and Zepbound, is a single molecule that activates both the GLP-1 and the GIP receptor, so it is called a dual agonist. Why adding GIP helps is still debated. Leading ideas are better appetite control, better handling of fat tissue and fewer side effects at a given dose, but no single explanation is settled.

• Appetite: receptors in the hypothalamus and brainstem reduce hunger and the pull of food, which patients often describe as quieter thoughts about eating.
• Stomach: slower gastric emptying makes meals feel larger and longer-lasting. This is also the main source of nausea.
• Pancreas: glucose-dependent insulin release lowers blood sugar with a low risk of hypoglycaemia (dangerously low sugar) when the drug is used alone.

The drugs do not burn fat directly. They change how much a person wants to eat, so the energy deficit comes from lower intake. That is why results depend on dose, and why stopping the drug tends to bring appetite, and weight, back (see chapter 5).

1. 1982-1987Work in Joel Habener's laboratory at Massachusetts General Hospital shows that the preproglucagon gene carries the code for glucagon and a second glucagon-related peptide in anglerfish (Lund et al., PNAS, 1982), and that synthetic GLP-1 (7-37) is a potent stimulator of insulin release in the perfused rat pancreas (Mojsov, Weir and Habener, Journal of Clinical Investigation, 1987).
2. 1992John Eng isolates exendin-4 from Gila monster venom (Journal of Biological Chemistry, 1992). It is structurally related to GLP-1 and acts on the GLP-1 receptor (Goke et al., Journal of Biological Chemistry, 1993), but lasts hours in the body rather than minutes (Byetta label: terminal half-life of 2.4 hours).
3. 2005FDA approves exenatide (Byetta), a twice-daily injection and the first GLP-1 drug, developed by Amylin with Eli Lilly.
4. 2010 and 2014Liraglutide (Novo Nordisk) is approved as Victoza for type 2 diabetes in 2010 and, at a higher dose, as Saxenda for weight in 2014. Dulaglutide (Trulicity, Lilly) follows in 2014.
5. Dec 2017Semaglutide is approved as Ozempic, a once-weekly injection for type 2 diabetes.
6. Sep 2019Rybelsus, the first oral GLP-1 (a semaglutide tablet with an absorption enhancer), is approved for type 2 diabetes.
7. Jun 2021Wegovy (semaglutide 2.4 mg weekly) is approved for chronic weight management.
8. May 2022 and Nov 2023Tirzepatide is approved as Mounjaro for type 2 diabetes (May 2022) and as Zepbound for obesity (Nov 2023).
9. Dec 2025 and Apr 2026An oral Wegovy pill (semaglutide) is approved in Dec 2025 and launched in the US on 5 Jan 2026. Lilly's orforglipron is approved in the US in Apr 2026 as Foundayo.

Sources for the approval years: the FDA's Drugs@FDA records of original approval dates (Byetta 28 Apr 2005, Victoza 25 Jan 2010, Trulicity 18 Sep 2014, Saxenda 23 Dec 2014, Ozempic 5 Dec 2017, Rybelsus 20 Sep 2019, Wegovy 4 Jun 2021, Mounjaro 13 May 2022, Zepbound 8 Nov 2023), the FDA approval letter for Wegovy tablets (22 Dec 2025), the FDA press release for Foundayo (1 Apr 2026), and Novo Nordisk's Q1 2026 report for the US launch of the Wegovy pill on 5 Jan 2026.

Early drugs lost 2-5% of body weight and needed injections once or twice a day, so they were diabetes drugs. Three steps changed that: weekly dosing, a higher dose aimed at obesity rather than diabetes, and a stronger molecule. In the pivotal trials, semaglutide 2.4 mg produced a mean weight change of -14.9% versus -2.4% on placebo at 68 weeks in 1,961 adults with obesity (STEP 1, Wilding et al., New England Journal of Medicine, Feb 2021). Tirzepatide's phase 3 programme showed -15.0%, -19.5% and -20.9% at 5, 10 and 15 mg versus -3.1% on placebo over 72 weeks (SURMOUNT-1, Jastreboff et al., New England Journal of Medicine, 2022).

Almost all of the market sits on two molecules. Semaglutide is sold by Novo Nordisk as Ozempic (type 2 diabetes), Wegovy (obesity and related indications) and Rybelsus (diabetes tablet). Tirzepatide is sold by Eli Lilly as Mounjaro (diabetes) and Zepbound (obesity and sleep apnoea). The same drug under two names exists for pricing, insurance and labelling reasons, not because the molecules differ.

Orforglipron deserves a note because it is built differently. The semaglutide pill is a peptide that needs an absorption enhancer and strict fasting rules. Orforglipron is a small molecule, which in principle is cheaper to make at scale and can be taken without fasting rules. Lilly reported Foundayo revenue of USD 184 million in Q3 2026 and USD 281 million in the first nine months (Lilly Q3 2026 release).

Cross-trial comparisons are unreliable because populations, durations and statistical methods differ (an efficacy estimand counts people who stay on drug, while a treatment-regimen estimand counts everyone randomised). The cleaner evidence comes from head-to-head trials. In SURMOUNT-5 (New England Journal of Medicine, 2025), an open-label 72-week trial, tirzepatide produced about 20.2% weight loss against about 13.7% for semaglutide 2.4 mg. Those two figures are recalled from the publication and were not re-verified in this research; check the paper before quoting.

• SELECT (semaglutide 2.4 mg, 17,604 adults with heart disease and overweight but no diabetes): major cardiovascular events occurred in 6.5% of the semaglutide group versus 8.0% on placebo, a hazard ratio of 0.80 (a 20% relative reduction) in the New England Journal of Medicine, Nov 2023. This led to the Mar 2024 Wegovy cardiovascular label.
• FLOW (semaglutide, people with type 2 diabetes and chronic kidney disease): about a 24% lower risk of the kidney, cardiovascular and death composite endpoint (NEJM, May 2024; recalled, not re-verified). Ozempic gained a kidney label in early 2025.
• SURPASS-CVOT (tirzepatide against dulaglutide in type 2 diabetes with heart disease): reported in 2025 as non-inferior on major cardiovascular events; Lilly's Q3 2026 release says FDA has approved Mounjaro to reduce cardiovascular risk.
• SUMMIT (tirzepatide, heart failure with preserved ejection fraction and obesity): about a 38% lower risk of the composite of cardiovascular death or a worsening heart-failure event (hazard ratio 0.62, median follow-up 104 weeks; Packer et al., New England Journal of Medicine, 2025).
• SURMOUNT-1 three-year extension in prediabetes: a 94% lower risk of progressing to type 2 diabetes on the efficacy estimand, and 93% on the treatment-regimen estimand (Lilly press release, 20 Aug 2024).

Tirzepatide has been the stronger weight-loss drug on the available head-to-head data, and Lilly's revenue has overtaken Novo's in the incretin class. Novo's response is a higher semaglutide dose (Wegovy 7.2 mg, approved by FDA in Mar 2026), the first oral obesity GLP-1 (the Wegovy pill, with more than 200,000 US weekly prescriptions by the week ending 17 Apr 2026, per Novo's Q1 report) and the combination CagriSema, discussed in chapter 3.

The pipeline follows three goals. Make the drug stronger, usually by hitting more receptors. Make it easier to live with, through fewer side effects, less lean mass loss, or pills. And find combinations that work at lower doses. The main field entrants are listed below with trial status as of 3 Nov 2026. A pipeline is a set of experiments: most drugs in it will not reach the market, and company timelines slip.

Retatrutide adds a third receptor, for glucagon. Glucagon normally raises blood sugar, but in combination it appears to raise energy expenditure and reduce liver fat. In TRIUMPH-1, 2,339 adults with obesity but without diabetes lost on average 17.6%, 23.7% and 25.0% of body weight at 4, 9 and 12 mg after 80 weeks, versus 3.9% on placebo (Jastreboff et al., NEJM, published online 29 Sep 2026). Lilly has said participants lost about 28% on average among those who stayed on treatment (company statement reported by the New York Times, May 2026). The trial also reported reductions in knee osteoarthritis pain and in sleep apnoea severity.

Reported watch items for retatrutide: a sensory side effect called dysesthesia (unusual skin sensations) and a higher rate of stopping because of side effects at the top dose than other drugs. One secondary summary put these at 12.5% and 11.3% respectively; those figures were not confirmed from primary data in this piece. Lilly has not announced a US submission date in its Q3 2026 release.

Amylin is a second satiety hormone made with insulin. Cagrilintide is a long-acting amylin analogue. CagriSema combines it with semaglutide. In REDEFINE-4, the trial against tirzepatide, CagriSema did not meet its primary endpoint (Novo, Q1 2026 report), and the weight-loss figures circulating for it are inconsistent between secondary sources, so none are quoted here. A related REIMAGINE 4 diabetes trial also missed non-inferiority against tirzepatide on HbA1c. Novo's own H1 2026 report terminated monlunabant (a different obesity drug) with a DKK 4.0 billion impairment and reports that ziltivekimab's ZEUS heart trial missed its primary endpoint.

Amycretin is a single molecule that activates both GLP-1 and amylin receptors, in both injected and oral forms. It is early; the company's reported phase 3 start is not mentioned in the H1 2026 filing, so treat the programme timeline as unconfirmed.

An injection weekly is accepted by many patients but limits uptake and complicates manufacture. Pills allow cheaper supply and wider prescribing. Novo launched the Wegovy pill on 5 Jan 2026 and reported US pill sales of DKK 3,141 million in Q2 2026 (DKK 5,397 million in H1). Lilly's orforglipron, approved in Apr 2026, generated USD 184 million in Q3. Other oral candidates are Viking's oral VK2735, Structure Therapeutics' aleniglipron and Pfizer's programme inherited with Metsera; none is approved.

• FDA decision on Novo's CagriSema (Novo lists Q4 2026) and on 25 mg oral semaglutide for diabetes (Q4 2026).
• Retatrutide regulatory filing and the remaining phase 3 readouts.
• Phase 3 start for eloralintide plus tirzepatide (Lilly, Q4 2026).
• Viking's VANQUISH readouts (guided to 2027) and its oral phase 3 start.
• Semaglutide Wegovy MASH decision with a Q1 2027 target (Novo H1 2026 report).

The hard-outcome trials in chapter 2 are the foundation. SELECT showed that in adults with established heart disease and overweight, semaglutide lowered heart attacks, strokes and cardiovascular death by about 20% relative to placebo. The effect appears larger than weight loss alone would predict, which has led researchers to suggest direct effects on blood vessels and inflammation, though the mechanism is not proven. In kidney disease, FLOW showed a roughly 24% lower composite event rate with semaglutide in people with type 2 diabetes. In HFpEF (heart failure where the heart pumps normally but is stiff), tirzepatide cut the composite of cardiovascular death and heart failure events by about 38% over two years in SUMMIT.

Obstructive sleep apnoea, in which the airway collapses during sleep, is strongly linked to excess weight. On 20 Dec 2024 the FDA approved Zepbound for moderate-to-severe sleep apnoea in adults with obesity, which the agency noted was the first drug for that use. In the TRIUMPH-1 trial retatrutide also reduced sleep apnoea severity. This label matters commercially because it lets insurers, including Medicare Part D in some conditions, cover the drug for a medical indication.

MASH (metabolic dysfunction-associated steatohepatitis, formerly NASH) is a fatty liver with inflammation and scarring that can progress to cirrhosis. The FDA expanded Wegovy to non-cirrhotic MASH with moderate-to-advanced fibrosis (stages F2 to F3) in Aug 2025, based on the ESSENCE trial. Novo reports FDA has accepted a filing for the Wegovy pill in MASH with a decision expected in Q1 2027 (H1 2026 report). Survodutide is also in a liver programme, and tirzepatide has phase 2 liver data.

Many patients report lower interest in alcohol, nicotine and other cravings. Early human studies are small: a 2025 randomised pilot of semaglutide in people with alcohol use disorder was reported to reduce drinking in a laboratory setting (n=48, recalled and not re-verified), and animal work shows reduced drug and alcohol intake. No regulator has approved a GLP-1 drug for any substance use disorder, and several larger trials are running. This is a hypothesis with some biological plausibility, not an indication.

The most prominent failure came in Alzheimer's disease. On 24 Nov 2025 Novo Nordisk announced that EVOKE and EVOKE+, two phase 3 trials of oral semaglutide in early symptomatic Alzheimer's, missed their primary endpoint (change on the CDR-SB cognitive and functional scale) after two years, even though some biomarkers improved. The company ended the one-year extension. A UK phase 3 trial of weekly exenatide in Parkinson's disease found no benefit on its main measure at 96 weeks (Vijiaratnam et al., Lancet, Feb 2025). Other setbacks sit elsewhere in the pipeline: Novo's monlunabant and the ZEUS heart trial of ziltivekimab, covered in chapter 3.

The four endpoints above are not comparable with each other: they measure different events in different populations over different periods. The chart shows the size of effect claimed in each trial, not a ranking of drugs.

• Where the disease is driven by body fat or metabolism (heart, sleep apnoea, liver, diabetes), the drugs have worked.
• Where the disease is primarily neurodegeneration (Alzheimer's, Parkinson's), the first large trials failed.
• Behavioural and addiction uses are biologically plausible and not yet proven in large trials.

The rest of this chapter covers side effects and safety. It is educational and is not medical advice: anyone considering or taking one of these drugs should talk to a clinician who knows their history.

Nausea, vomiting, diarrhoea, constipation and abdominal discomfort are the most common effects across the class. They are usually worst when a dose is raised and tend to ease over time, which is why labels use a gradual dose escalation. In the phase 2 trial in type 2 diabetes, 62-89% of participants on orforglipron had any adverse event, with digestive effects in 44-70% versus 18% on placebo, mostly mild to moderate (Frias et al., Lancet, 2023). Discontinuation rates in trials run from low single digits to above 10% depending on drug and dose.

• Gallbladder disease: gallstones can form during rapid weight loss.
• Pancreatitis: the evidence is mixed. Some studies show no increase, while the UK regulator MHRA warned in January 2026 of a small risk of severe acute pancreatitis with tirzepatide. Labels carry a pancreatitis warning.
• Thyroid: US labels carry a boxed warning for thyroid C-cell tumours, based on rodent studies. The drugs are contraindicated for people with a personal or family history of medullary thyroid cancer or MEN 2. Large human studies have not shown a clear increase.
• Eye: a rare optic nerve condition, NAION (non-arteritic anterior ischaemic optic neuropathy, a sudden loss of vision), has been linked to semaglutide in several studies, including a 2025 JAMA Ophthalmology study in people with diabetes. European regulators reportedly added it to the semaglutide label as a very rare effect in 2025 (recalled, verify with EMA). Separately, early worsening of diabetic retinopathy has been seen when blood sugar falls rapidly.
• Anaesthesia: slowed stomach emptying can raise the risk of aspiration; a 2024 multi-society guidance suggested pausing doses before procedures, with specifics varying.
• Mental health: the FDA requested removal of the suicidal behaviour and ideation warning from weight-loss labels in January 2026, after reviews found no clear causal link (FDA Drug Safety Communication, 13 Jan 2026).

Any large weight loss reduces both fat and lean mass (muscle plus other tissue such as water and organs). In trials that used body-scan substudies, lean mass typically made up a meaningful minority of lost weight, often quoted at 25-40% (a range recalled from several reports, not re-verified). That is similar in proportion to what is seen with diet-induced weight loss of similar size, but because these drugs lose so much weight, the absolute lean-mass loss is larger. The open questions are whether the lost lean mass is clinically harmful, especially in older adults, and whether resistance exercise and adequate protein can offset it. These questions are why several companies run trials of drugs that add muscle-preserving agents (for example, myostatin and activin inhibitors) to a GLP-1.

Obesity behaves like a chronic condition. After stopping, people regain weight quickly. In the STEP 1 extension, participants regained about two-thirds of their prior weight loss one year after stopping semaglutide (Wilding et al., Diabetes, Obesity and Metabolism, 2022), and a 2026 BMJ meta-analysis of 37 studies found regain of about 0.4 kg a month on average after stopping weight-management drugs (West et al., BMJ, Jan 2026). Cost is a major reason for stopping: in a review of 288 patients at one US health system who stopped injectable semaglutide or tirzepatide within the first year, 47.6% did so because of cost or insurance problems (Gasoyan et al., Obesity, Dec 2025). Real-world discontinuation in the first year is substantial in published claims data, which weighs on the long-term revenue model (chapter 7).

During shortages in 2022-2025, compounding pharmacies made unapproved copies of semaglutide and tirzepatide. The FDA declared the tirzepatide shortage over in Oct 2024. After a lawsuit by compounders it re-evaluated and confirmed that decision in Dec 2024, and gave compounders until 18 Feb 2025 (503A pharmacies) and 19 Mar 2025 (503B outsourcing facilities) to stop copying tirzepatide (FDA, 19 Dec 2024 update). Novo's chief executive estimated up to 1.5 million US users of compounded GLP-1 products as of January 2026 (Reuters, 12 Jan 2026). On compounded semaglutide, Novo's Q1 2026 report says a US court denied a preliminary injunction on 24 Apr 2025, ending FDA enforcement discretion for 503A pharmacies, that the 503B period ended on 22 May 2025, and that a decision on the compounders' appeal is expected before the end of 2026. The FDA has received reports of dosing errors with compounded products; patients should know what they are buying.

In the third quarter of 2026 Lilly reported revenue of USD 24.4 billion, up 39% from USD 17.6 billion a year earlier. Mounjaro sold USD 10.7 billion (up 65%) and Zepbound USD 5.4 billion (up 49%). For the first nine months revenue was USD 67.2 billion, up 46%. Lilly raised full-year 2026 revenue guidance to USD 91-92 billion from USD 85-87 billion (Lilly Q3 2026 earnings release, 30 Oct 2026). Novo Nordisk's Q3 2026 results had not been confirmed as published when this piece was written (an earnings calendar listed an estimated date of 4 Nov 2026); Novo's latest verified figures are for H1 2026.

Novo is more mixed. Reported H1 2026 sales were DKK 175.3 billion, flattered by a USD 4.2 billion reversal of a 340B (US drug discount programme) provision in Q1; excluding it, adjusted sales were DKK 148.6 billion, about 2% higher at constant exchange rates. In Q2 2026 Ozempic sold DKK 31.4 billion, Wegovy injection DKK 19.5 billion, the Wegovy pill DKK 3.2 billion and Rybelsus DKK 5.2 billion. Novo's 2026 outlook was narrowed on 4 Aug 2026 to adjusted sales and operating profit growth of 0% to -6% at constant exchange rates, from -4% to -12% in May (H1 2026 report).

Lilly's Q3 2026 revenue growth of 39% combined a 53% rise in volume with a 15% fall in realised prices. In the US, volume was up 41% and prices fell 7%. Outside the US, volume was up 76% and prices fell 29%, driven mainly by Mounjaro's inclusion in China's National Reimbursement Drug List in Q1 2026 (Lilly Q3 2026 release).

• Nov 2025: Lilly and Novo agreed Most Favoured Nation style pricing deals with the US administration (Novo H1 2026 report: access via Medicare Part D, Medicaid and direct-to-patient self-pay). Press coverage at the time described TrumpRx cash prices of about USD 350 a month for injectables and a Medicare price of USD 245 a month with a USD 50 patient copay; those were announcements, and the exact current prices were not confirmed from primary sources.
• Wegovy pill self-pay price: USD 149-299 a month by dose (Novo H1 2026 report).
• From 1 Jan 2027, Novo will cut the US list price (WAC) of listed Wegovy and Ozempic doses to USD 675 a month, about 50% off for Wegovy and 35% off for Ozempic (Novo Q1 and H1 2026 reports).
• Medicare GLP-1 Bridge: started 1 Jul 2026 and runs through 31 Dec 2027; eligible beneficiaries pay a USD 50 monthly copay; covers Wegovy, Zepbound and Foundayo. KFF estimated 3.8 million Part D enrollees met the eligibility criteria on 2023 data (an eligibility count, not enrolment).
• Employer coverage: KFF reported that 43% of the very largest employers covered these drugs for obesity, up from 28% the year before (the survey year was not stated in the retrieved page; treat as indicative).
• Pharmacy benefit managers: Novo's filing says CVS Caremark will add other weight-loss drugs to its largest commercial formularies from 1 Oct 2026, ending Wegovy's preferred position; a secondary report said Foundayo got equal access from 1 Jun.

The FDA shortages for tirzepatide (ended Oct 2024) and semaglutide have been resolved, which removes the legal basis for most large-scale compounding, though enforcement is contested in court (chapter 5). Lilly and Novo have invested heavily in plants; Novo's Holdings parent bought Catalent in Dec 2024 to get fill-finish capacity (recalled, verify).

Retrieved sources for this chapter are thinner than for the earlier ones. Where a figure could not be confirmed it is described as a gap rather than estimated.

A drug taken indefinitely by a large share of adults is a budget question. KFF estimated that about 36 million people with employer insurance might qualify medically for these drugs for weight loss, compared with about 24 million covered under the plans surveyed (as reported in a press summary; the year was not stated). KFF's president said employer premiums were expected to rise more sharply the next year, citing GLP-1 drugs, hospital prices and tariffs. Medicare has historically been barred by statute from covering weight-loss drugs; the GLP-1 Bridge runs as a time-limited pilot from 1 Jul 2026 to 31 Dec 2027 at a USD 50 copay, so its longer-term form is not settled.

Payers weigh the drug cost against savings from fewer heart events, less diabetes, fewer joint replacements and less sleep apnoea. The outcome trials in chapter 2 support part of that case, but savings accrue over years and often to a different payer from the one who pays now (for example, an employer pays for a drug whose heart benefits show up in Medicare after 65). The retrieved sources did not include an audited estimate of net savings.

Lilly's realised price fell 15% in Q3 2026 while volumes rose 53%. Novo's list price cut for 2027 (to USD 675) and the self-pay prices of USD 149-299 on the pill show that the US price of a month of treatment is falling toward the low hundreds of dollars from above USD 1,000. For governments, this shifts the affordability case; for the manufacturers, it means revenue depends on reaching many more patients.

The retrieved sources did not contain company-reported or survey data on the effect of GLP-1 use on food and beverage sales, so this piece does not quote figures. The mechanism is straightforward: reduced appetite means lower calorie purchases per household, and survey work by consumer-goods firms and academic panels has pointed to lower spending on snacks, sweets and alcohol among households with a GLP-1 user. Readers should look to the earnings commentary of packaged-food, restaurant and beverage companies and to panel data from retail researchers for current, sourced numbers.

Exposure runs in two directions. Fewer joint replacements, bariatric surgeries, sleep-apnoea devices (CPAP) and some cardiac procedures are the possible headwinds; companies in those areas have publicly discussed the question. Meanwhile, injectors, needles, vials, stoppers and autoinjector assemblies are tailwinds for their suppliers. The retrieved sources contain no audited quantification of either effect.

Health insurers carry the cost of the drugs in pharmacy benefits and bear medical-cost trends in their commercial and Medicare books. The CVS Caremark formulary changes described in chapter 6 show the benefit managers bargaining for rebates by granting or removing preferred positions. Lilly's Q3 2026 release cites pricing pressure and its voluntary agreement with the US government on drug pricing and access among its risk factors.

India, Canada, Brazil and China are the first large generic semaglutide markets. In India many firms launched within days of the patent expiry in Mar 2026, which is expected to push prices far below US levels. Wegovy 7.2 mg was approved in the UK on 14 Apr 2026 and orforglipron received UK approval in Aug 2026 and a positive EU opinion in Oct 2026. Supply, cold-chain distribution and health-system budgets still limit use in low-income countries.

This chapter sets out the arguments critics make, with the evidence behind each. It is not a forecast, and it is balanced by the earlier chapters.

Governments are now direct negotiators. The Nov 2025 US agreements, the Medicare Bridge at a USD 50 copay, Novo's 2027 list price cut of 35-50%, and China's reimbursement listing (which cut Lilly's realised ex-US price by 29% in Q3 2026) show the direction. Lilly's global realised price was already down 15% in Q3 2026. If the market eventually settles at a low hundreds of dollars a month, the revenue pool depends on volume reaching a very large share of the eligible population.

Novo's adjusted 2026 sales are guided to be flat to down 6% at constant exchange rates, Ozempic sold DKK 59.2 billion in H1 2026 (down 6% in DKK), and the company's head-to-head tests of CagriSema against tirzepatide missed their endpoints. Lilly's guidance of USD 91-92 billion shows how far ahead the leader is. Competition is also arriving from Amgen, Pfizer, Roche, Boehringer, Viking, Structure, and from Chinese developers, any of which could enter within the next three to five years if trials succeed.

Generic semaglutide is already on sale in India and entering other markets in 2026. Novo said Canadian loss of exclusivity has lowered realised prices. US and European exclusivity runs to the early 2030s, which gives incumbent protection at home, but a growing share of the world's patients will not use branded semaglutide.

The class has a boxed warning on thyroid tumours (from animal data), an emerging optic-nerve signal, regulator warnings on pancreatitis, aspiration risk before anaesthesia and open questions about lean mass. Large real-world databases will keep producing new associations, some real and some artefacts. A confirmed serious safety finding would affect label language, prescribing and payer coverage.

Because weight returns after stopping, benefits require staying on therapy for years. Discontinuation for cost and side effects is high in claims data. A cheaper, tolerable pill could improve persistence, but every discontinuation also reduces the long-run revenue per starter. Lilly and Novo both report large volume growth, but net persistent users are what the revenue model depends on, and that figure is not in the retrieved company reports.

The Alzheimer's trials (Nov 2025), the REDEFINE-4 and REIMAGINE 4 misses, the termination of monlunabant with a DKK 4.0 billion impairment and the ZEUS miss show the platform is not a universal solvent. Some anticipated indications will not materialise, and several expected next-generation drugs have disappointed relative to tirzepatide.

Up to 1.5 million US users were estimated to be on compounded products in January 2026 (Novo's CEO, as reported). A US court ruling in Apr 2026 favoured the manufacturers and an appeal decision is expected before year-end, and unapproved or counterfeit supply continues to create both commercial leakage and patient-safety risk.

The pricing agreements are voluntary arrangements with an administration, and their terms depend on political continuity. Medicare's Bridge is a pilot through 2027. Any change to those arrangements, tariffs, or statutory reform of Medicare's weight-loss exclusion could move sales.

This map lists listed companies with disclosed or widely reported exposure to GLP-1 and related drugs, and what that exposure is. It states facts as retrieved or recalled and flags where something was not verified. It is not a recommendation to buy or sell anything. Tickers are listed for identification only.

Indirect exposure runs through companies whose revenue depends on volumes that GLP-1 use may change: sleep-apnoea devices, joint replacement and bariatric surgery products, packaged food and beverage, restaurants and alcohol. Their reported commentary is the primary source for any such effect; none of it is quantified here.