In a groundbreaking comparison of leading obesity medications, those administered Eli Lillyโs drug Zepbound saw nearly 50% greater weight reduction compared to individuals taking Novo Nordiskโs Wegovy, marking a major breakthrough in weight-loss treatment. This landmark study revealed participants using tirzepatide, frequently sold as Zepbound, experienced an average weight loss of 50 pounds (22.8 kilograms) over a 72-week period. In contrast, individuals on semaglutide, known commercially as Wegovy, shed around 33 pounds (15 kilograms). These findings were detailed in research financed by Lilly and recently published in the New England Journal of Medicine.
Both Zepbound and Wegovy belong to a novel category of drugs that replicate specific gut and brain hormones which modulate hunger and satiety. However, Zepbound distinguishes itself by targeting two hormones, GLP-1 and GIP, whereas Wegovy targets only GLP-1, according to Dr. Louis Aronne, head of the Comprehensive Weight Control Center at Weill Cornell Medicine. โUsing two drugs simultaneously can enhance weight loss outcomes,โ Aronne commented, having spearheaded the research and unveiled the results at the European Congress on Obesity in Spain.
Despite Zepboundโs superior results in what Aronne described as โa race of efficacy,โ both drugs offer valuable options for managing obesity, a condition impacting nearly 40% of U.S. adults. โThese medications aim to promote health improvements,โ Aronne remarked, highlighting that not everyone would require the most potent option.
The study involved 751 participants from various U.S. locations, characterized by being overweight or having obesity paired with at least one other weight-related health concern, excluding diabetes. Participants received weekly injections at the highest tolerable doses of Zepbound (10 or 15 milligrams) or Wegovy (1.7 or 2.4 milligrams).
By the conclusion of the study, individuals administered Zepbound lost approximately 20% of their body weight on average, unlike the near 14% reduction experienced by Wegovy users. Additionally, Zepbound recipients decreased their waist size by roughly 7 inches (17.8 centimeters), while those on semaglutide reduced theirs by about 5 inches (12.7 centimeters). Further analysis indicated over 32% of Zepbound users lost no less than a quarter of their body weight, in contrast to about 16% among Wegovy users.
Gender discrepancies were noted as weight loss was reported to be around 6% less in men compared to women across both drug categories. As subjects from both cohorts experienced weight loss, they noted improvements in critical health indicators such as blood pressure, cholesterol, and blood sugar levels.
Overall, more than three-quarters of patients using either medication encountered at least one side effect, usually gastrointestinal issues of mild to moderate severity, like nausea, constipation, diarrhea, and vomiting. It was observed that approximately 6% of Zepbound users withdrew from the trial due to adverse effects, compared to 8% of those on semaglutide.
The use of GLP-1 drugs has surged in popularity, with at least 1 in 8 U.S. adults reportedly using them, as per a 2024 survey by an independent health policy research group. While Zepboundโs global sales reached $4.9 billion last year, Wegovy amassed nearly $8.8 billion.
Challenges such as accessibility and affordability have hindered the broader usage of these medications. Recently, both tirzepatide and semaglutide were removed from the U.S. Food and Drug Administrationโs list of drug shortages. Additionally, both companies have introduced initiatives lowering costs to approximately $500 per month or even less, varying based on dosage.
Other considerations influencing drug access have emerged, such as CVS Healthโs announcement that Wegovy will become their preferred option within their standard drug formulary effective July 1, thereby excluding Zepbound. Provision of diverse treatment options remains essential in addressing an extensive issue like obesity in the U.S., according to Dr. Angela Fitch, chief medical officer of a medical group specializing in obesity care. She pointed out Wegovyโs proven ability to reduce serious cardiac risks by 20%. Dr. Fitch emphasized that different patients may respond uniquely to various treatments: โConsidering the large number of patients requiring treatment, weโre going to have to deploy all available medications effectively.โ