The GLP-1 Drug Revolution

The U.S. Food and Drug Administration (FDA) approved exenatide, marketed as Byetta by Amylin Pharmaceuticals and Eli Lilly, as the first GLP-1 receptor agonist for type 2 diabetes. Exenatide, a synthetic version of a peptide found in Gila monster venom, was administered by twice-daily injection and improved blood sugar control while promoting modest weight loss, opening the therapeutic class that would later transform obesity treatment.

The FDA approved Novo Nordisk's liraglutide, marketed as Victoza, as a once-daily GLP-1 agonist for type 2 diabetes. Liraglutide was the first GLP-1 drug to demonstrate cardiovascular benefits and became a top-selling diabetes medication. Its approval established Novo Nordisk as the dominant player in the GLP-1 class.

The FDA approved liraglutide (marketed as Saxenda) for weight management in adults with obesity, making it the first GLP-1 agonist approved for chronic weight management. The approval signaled a shift in the medical treatment of obesity from short-term interventions to long-term pharmacological management, though average weight loss of about 5-8 percent was modest compared with later drugs in the class.

The FDA approved Novo Nordisk's semaglutide, marketed as Ozempic, for type 2 diabetes. Administered as a once-weekly injection, semaglutide demonstrated superior blood sugar control and significantly greater weight loss than earlier GLP-1 drugs. Ozempic became a blockbuster, and the name later entered popular culture as shorthand for the entire drug class.

The FDA approved a higher-dose formulation of semaglutide, marketed as Wegovy, for chronic weight management in adults with obesity or overweight with at least one weight-related condition. Clinical trials showed average weight loss of approximately 15 percent over 68 weeks, far exceeding previous pharmacological treatments. Demand quickly outstripped supply, and the drug faced global shortages. Novo Nordisk's market value rose to make it Europe's most valuable company.

The FDA approved Eli Lilly's tirzepatide, marketed as Mounjaro, for type 2 diabetes. Tirzepatide is a dual agonist targeting both GLP-1 and GIP receptors, and trials showed average weight loss exceeding 20 percent, establishing a new benchmark for the class. Its approval intensified competition between Novo Nordisk and Eli Lilly in the obesity market.

Novo Nordisk announced results from the SELECT trial, a five-year study of more than 17,600 patients, showing that semaglutide reduced the risk of major adverse cardiovascular events by 20 percent in adults with obesity and established cardiovascular disease but without diabetes. The finding reframed GLP-1 drugs from metabolic treatments to potential cardiovascular therapies and expanded the rationale for widespread use.

The FDA approved Eli Lilly's tirzepatide, marketed as Zepbound, for chronic weight management, making it the most effective obesity medication approved to date. In 2023, semaglutide was the nineteenth most commonly prescribed medication in the United States with more than 25 million prescriptions. The scale of demand contributed to sustained supply shortages of both semaglutide and tirzepatide, and a market in compounded versions grew.

The FDA expanded Wegovy's approval to reduce the risk of major adverse cardiovascular events (cardiovascular death, non-fatal heart attack, or non-fatal stroke) in adults with established cardiovascular disease who are obese or overweight. This was the first FDA approval of an obesity medication for cardiovascular risk reduction, further expanding the medical rationale for prescribing GLP-1 drugs beyond weight management.

The FDA approved an oral version of semaglutide for weight management, marketed under the brand name Wegovy. The approval made semaglutide available as a daily pill rather than a weekly injection, potentially expanding access. By 2025, GLP-1 drugs had become a defining force in global health and economics, with effects extending into food industry investment, insurance policy debates, and public discussion of weight and body image.

The U.S. FDA approved Eli Lilly's Foundayo (orforglipron), the first small-molecule oral GLP-1 receptor agonist authorized for chronic weight management. Unlike injectable peptide drugs, the once-daily pill requires no refrigeration, a shift with major implications for global access and manufacturing scale. The approval, issued just 50 days after filing under the FDA's National Priority Voucher pilot program, ignited a commercial battle with Novo Nordisk's oral semaglutide, and Lilly reported capturing more than 30 percent of new U.S. oral obesity patients within months.

The U.S. Court of Appeals for the Fifth Circuit affirmed the FDA's removal of semaglutide and tirzepatide from the national drug shortage list, ending the legal basis for outsourcing facilities to mass-produce copycat versions of Ozempic, Wegovy, Mounjaro and Zepbound. The unpublished per curiam opinions resolved litigation brought by the Outsourcing Facilities Association and compounders, who had challenged the FDA's determination that the shortages were resolved after Novo Nordisk and Eli Lilly expanded manufacturing capacity. Patient-specific compounding under the 503A pathway remained legal for documented medical needs, but the bulk channel that had made cheaper compounded GLP-1s widely accessible through telehealth providers was shut down. Patient advocates warned the decision would raise out-of-pocket costs for those who had relied on compounded versions, as brand-name GLP-1s often cost more than 1,000 dollars per month without insurance.

On August 28, 2026, the U.S. FDA approved Eli Lilly's Mounjaro (tirzepatide) to reduce the risk of major adverse cardiovascular events -- heart attack, stroke, and cardiovascular death -- in adults with type 2 diabetes at high cardiovascular risk. Based on the SURPASS-CVOT trial, in which tirzepatide showed a lower rate of major heart events than Lilly's older GLP-1 drug Trulicity (dulaglutide), the approval made Mounjaro the first GIP and GLP-1 receptor agonist to gain a cardioprotective indication. The decision extended the cardiovascular-protection franchise of the drug class beyond Novo Nordisk's semaglutide products, establishing cardioprotection as a class-wide feature rather than a benefit of a single medicine.

Health Canada granted marketing authorisation to Sandoz Semaglutide, a generic version of Ozempic, making Canada the first major developed market to authorise a generic of the drug class's defining medicine. The approval marked the start of the GLP-1 class's transition from patent-protected monopoly pricing toward generic competition: Sandoz cited a Canadian GLP-1 market of roughly 2.6 billion US dollars and nearly 12 million semaglutide injection pens issued annually. Sandoz paired it with a US FDA-accepted generic tirzepatide filing and semaglutide approval in Brazil, while Novo Nordisk moved to shield its remaining patent estate.

Novo Nordisk announced topline Phase 3 results from the REIMAGINE 5 trial showing its next-generation drug CagriSema (cagrilintide plus semaglutide) delivered an estimated average weight loss of 12.4 percent in patients with type 2 diabetes, outperforming Lilly's tirzepatide at 9.1 percent - the first head-to-head trial in which a Novo Nordisk therapy demonstrated superior weight loss against tirzepatide. The results, alongside the REDEFINE 9 trial, shifted the competitive balance in the intensifying Novo-Lilly obesity drug rivalry.