Of course, there had been movement over the years. Novo Nordisk’s Saxenda – a twice-daily formulation of liraglutide – became the first GLP-1 approved specifically for obesity in 2014. Semaglutide followed in the US in December 2017 under the brand name Ozempic, again for Type 2 diabetes. Important steps, certainly, but nothing compared with what was to come.

The real inflexion point came on 4th June 2021, when the US FDA approved semaglutide 2.4 mg for chronic weight management under a new name – Wegovy. On paper, this was a subtle shift. Ozempic had already begun to make waves online as the secret weapon for celebrity weight loss (despite not being approved for this indication). For the everyday patient, it appeared out of reach.

But with Wegovy – a once-weekly injection delivering close to 10% weight loss, priced comparably to Saxenda, yet offering markedly stronger efficacy and far greater convenience – Novo Nordisk had officially opened the floodgates. For the first time, the promise of an obesity treatment went beyond clinical credibility. It was scalable.

Even optimistic forecasts struggled to keep pace with what followed. Novo Nordisk’s rise was nothing short of meteoric, and the framing of obesity began to change with it – from specialist interest to commercial centre stage. After decades of stalled innovation and limited pharmacological options, patients and prescribers responded to something that felt different; a treatment that did not hinge solely on willpower or punitive lifestyle narratives. Understandably, demand skyrocketed – quickly outstripping manufacturing capacity and leaving the Danish company racing to expand supply.

At that stage, Novo Nordisk appeared be in a league of its own as true head-to-head competition in obesity had yet to materialise. But, behind the scenes, the direction of travel was clear. Eli Lilly, already deeply embedded in the diabetes space, ramped up its own GLP-1 ambitions. Pfizer and AstraZeneca quickly followed suit, signalling renewed intent in metabolic disease across the industry. The race, it seemed, was beginning to gather pace.

Through 2022, this momentum only intensified. Off-label prescribing blurred the neat regulatory lines between diabetes and obesity, even as authorities worked to maintain that distinction. In tandem, brand names like Wegovy and Ozempic – chemically identical, differently branded – slipped into the cultural zeitgeist, referenced far beyond the bounds of endocrinology clinics. In the closing three months of the year, US healthcare providers wrote more than nine million prescriptions for Ozempic, Wegovy, and other GLP-1 drugs, with Novo’s Ozempic making up more than 65% of total prescriptions – primarily off-label for weight loss purposes. Evidently, GLP-1s had done something that few drug classes ever do: they had caught the general publics’ attention.

In August, study results published in the NEJM showed in a randomised trial of 529 people with obesity and heart failure, those on semaglutide had almost double the heart improvement after one year, and could walk 20 metres more in six minutes, than those in the placebo group. Later that month, Novo Nordisk revealed results from its SELECT cardiovascular outcomes trial, which demonstrated that semaglutide significantly reduced major adverse cardiovascular events in people with obesity and established heart disease.

Together, these studies showed that GLP-1s were proven cardiometabolic modifiers with hard clinical endpoints, opening up new avenues for the competitive landscape. Companies lacking comparable outcomes data found themselves at a strategic disadvantage, even before any formal label expansions were secured.

November 2023 delivered the regulatory milestone many had anticipated. The FDA approved tirzepatide for chronic weight management under the name Zepbound, bringing Eli Lilly into direct competition with Wegovy. While other players remained active, the pace required to close the gap had become more demanding as the competitive landscape narrowed into a clear head-to-head dynamic.

Pfizer’s efforts illustrated that reality. The company pursued an oral GLP-1 candidate, seeking differentiation through convenience, yet encountered clinical hurdles. By the end of 2023, it had discontinued a twice-daily programme after patients reported significant gastrointestinal side effects. The episode underscored a challenge that would become a recurring issue for GLP-1 developers: mechanisms with powerful metabolic effects often carry tolerability trade-offs that cannot be engineered away easily.

While the evidence supporting GLP-1s was mounting, the same could not be said for supply. Facing unprecedented demand for both on and off-label use, manufacturers simply couldn’t keep pace. Consequently, active ingredients including semaglutide, liraglutide, and dulaglutide found their way onto global shortages lists.

On 2nd January 2024, the UK’s Department of Health and Social Care issued a national patient safety alert warning that GLP-1 shortages would likely persist through at least the end of the year. What had begun as a commercial success story was now a systems challenge. Demand had so thoroughly outpaced manufacturing capacity that continuity of care for people with type 2 diabetes was at risk and prescribers were urged not to initiate GLP-1 therapies outside their approved indications while constraints remained in place.

Scarcity at the clinic coexisted with historic scale in the capital markets. The industry’s new golden goose had begun to lay serious eggs. By July, semaglutide and tirzepatide ranked among the world’s most prescribed (and most lucrative) medicines. Novo Nordisk’s growth pushed it to become Europe’s most valuable listed company, with a market capitalisation of around $570 billion. One company was now exceeding the annual GDP of Denmark. By October, tirzepatide had propelled Eli Lilly to the top of the global pharmaceutical rankings. The irony was difficult to miss.

Within pipelines, attention was already shifting. First-generation injectables still drove prescriptions, but 2024 brought growing focus on next-generation combinations. Novo Nordisk advanced CagriSema, pairing cagrilintide with semaglutide, while Eli Lilly progressed retatrutide. Investor commentary increasingly framed the competition as: protect the current franchise while building broader, potentially more potent successors.

In the US, the trajectory took a slightly different turn toward the end of the year. The FDA approved Amneal’s generic exenatide injection, marking the first generic GLP-1 to reach the market. Shortly beforehand, AstraZeneca announced it would discontinue Byetta, one of the earliest agents in the class. The class had matured enough to enter a generic era, even as innovation continued at the leading edge. The immediate pricing impact was modest, but the direction was clear.

By December, the FDA’s supply updates painted an uneven picture. Tirzepatide injections were no longer listed as in shortage, while dulaglutide, semaglutide, and liraglutide remained constrained, with availability varying by presentation. Recovery was molecule-specific, rather than uniform, reinforcing the sense that resolution would be staggered, rather than decisive.

In short, by late 2024, the GLP-1 landscape looked markedly different from where it had begun.

Eli Lilly moved quickly to translate this clinical win into commercial momentum. And it worked; in the US, Zepbound overtook Wegovy in weekly prescriptions.

Beneath the headline rivalry, access dynamics were also evolving. As branded supply slowly began to stabilise, the FDA moved to dismantle the temporary compounding ecosystem that had emerged to fill the gaps caused by shortages. In February, 503B facilities were formally put on notice that by May, compounding products – including those distributed through telehealth channels – were expected to exit the market.

With compounded copies exiting the market, brand manufacturers regained control over pricing, messaging, and patient pathways. But they also faced a new kind of competition. Late 2024 had already seen the launch of the first generic exenatide, and in August 2025 the FDA approved the first generic version of liraglutide (Saxenda) for weight loss, with Teva launching immediately. For the first time, GLP-1s began to split into tiers – premium, next-generation injectables on one end, and lower-cost legacy molecules on the other.

While price pressure loomed at the older end of the class, innovation accelerated at the top. Novo Nordisk entered 2025 under visible competitive strain, but the company secured a major strategic win in August when subcutaneous Wegovy became the first GLP-1 approved for metabolic dysfunction-associated steatohepatitis (MASH). This reinforced Novo’s long-running strategy of positioning GLP-1s as disease-modifying cardiometabolic therapies, rather than cosmetic weight-loss drugs. Earlier in the year, the FDA had also approved a new Ozempic indication to reduce the risk of kidney disease progression and cardiovascular death in adults with type 2 diabetes and chronic kidney disease, further anchoring semaglutide in hard clinical outcomes.

At the same time, the geographic footprint of GLP-1 competition expanded rapidly. Eli Lilly launched Mounjaro in China in January, followed by India in March and Brazil in May, before bringing Zepbound to Canada in July. Novo Nordisk responded by launching Wegovy in June and Ozempic in December in key markets.

However, by mid-year, questions emerged around Novo Nordisk’s future in multiple territories, most notably, Canada, China, and India. Reporters discovered that Novo had allowed so-called “core patents” to expire. While these are just one part of the company’ extensive patent arsenal, the “loss of exclusivity” would allow biosimilar competitors to enter these markets.

Oral GLP-1s added another layer of competitive tension. Throughout 2025, anticipation had been growing around multiple promising FDA decisions for oral semaglutide, including a high-dose Wegovy pill for weight loss and cardiovascular risk. Novo secured regulatory momentum with FDA clearance for its oral Wegovy programme, while also experiencing setbacks, including disappointment around Alzheimer’s disease data.

These mixed results reflected the broader challenge of the oral race: convenience alone was no longer enough to guarantee success – oral candidates would have to demonstrate durability, safety, and cardiometabolic value comparable to injectables.

If Eli Lilly’s leadership team is to be believed, the company is on track to climb even higher in 2026, predicting strong sales and profit growth, even amid ongoing pricing pressures. For Novo Nordisk, the outlook is considerably bleaker. Once the poster child for the category, it appears the years of double digit yearly gains are coming to an end for the Danish company, with 2026 sales expected to fall between 5% and 13%.

Outside of the US, generics manufacturers are poised to pounce as soon as semaglutide patents expire. While Novo Nordisk and Eli Lilly currently dominate India’s premium obesity segment, regulators have been explicit that affordability remains a major barrier. And when semaglutide loses patent protection in 2026, generic entry is widely expected to reset access at scale. The response from Indian manufacturers suggests that this will not be a slow or cautious transition. More than ten companies, including Sun Pharma, Cipla, Dr Reddy’s, and Zydus, have already sought regulatory clearance to conduct Phase III trials for injectable and oral semaglutide, with a notable concentration on oral formulations.

China presents a parallel, though legally more complex, trajectory. Patent rulings suggest that, while Novo Nordisk’s compound patent will be respected until expiry, there will be little appetite for extension beyond March 2026. By that point, at least 17 semaglutide candidates are expected to be in late-stage development or pre-market application, including multiple programmes specifically targeting obesity. Unlike earlier waves of generic competition, many Chinese manufacturers already have experience producing and commercialising GLP-1s, raising expectations of fast market entry once the legal window opens.

Canada is also expected to become an early test case for post-exclusivity GLP-1 dynamics. With key semaglutide patents lapsing in 2025 and no effective supplementary protection in place, generic and biosimilar entry could begin as in the opening months of 2026. Multiple companies have already filed or signalled applications, and domestic manufacturing plans are being publicly discussed. This has prompted a different kind of concern: whether lower-priced Canadian semaglutide could leak into the US through grey or illicit channels while American patents remain intact well into the 2030s.

Overlaying all of this is the expanding role of oral GLP-1s. By 2026, oral semaglutide is likely to be established in protected markets, though at premium pricing. Attempts by digital health and direct-to-consumer operators to replicate or bypass regulatory pathways are already attracting scrutiny.

Taken together, GLP-1 innovation and access trends over the past five years paint a picture of a market that is as invigorating and complex as the molecules that comprise it. It is far from perfect, and drugmakers and regulators alike will undoubtedly spend a great deal of time wrestling with the particulars to ensure that patients can benefit from the most effective products on the market, particularly as new challengers enter the arena. But while many questions around GLP-1s are yet to be answered, one thing is for certain: It is a very exciting race to watch unfold.