A new study comparing two popular weight-loss medications, Zepbound and Wegovy, has shed light on their effectiveness, revealing key differences in the amount of weight lost by patients over an 18-month period.
In a recent trial, conducted by Eli Lilly, Zepbound, which targets both the GLP-1 and GIP hormones, resulted in an average weight loss of about 20% of body weight. In contrast, Wegovy, made by Novo Nordisk and working on the GLP-1 hormone alone, led to a 14% weight loss. This head-to-head comparison marks the first direct study of the two medications, which had previously been tested separately by their respective manufacturers.
The primary difference between the drugs lies in their targeting of hormones. Wegovy works by activating GLP-1, a hormone that suppresses appetite and helps the pancreas regulate blood sugar. Zepbound, on the other hand, impacts both GLP-1 and GIP, another hormone that also stimulates insulin production, potentially enhancing its weight-loss effect.
Dan Skovronsky, chief scientific and medical officer at Lilly, emphasized that the trial was conducted to address confusion among doctors and patients regarding which medication might be more effective. “Now we have head-to-head data to add to that conversation, and we’ve shown that Zepbound gives superior weight loss,” he said in a press release.
The study also found that Zepbound was associated with less nausea and vomiting, a common side effect of weight-loss medications. Skovronsky suggested that this could be linked to the GIP hormone’s action in the brain, which helps suppress nausea.
While Zepbound showed better weight-loss results, Novo Nordisk highlighted other benefits of Wegovy, particularly its cardiovascular effects. In March, the U.S. Food and Drug Administration (FDA) approved the addition of a new label for Wegovy, confirming its ability to reduce the risk of heart attacks, strokes, and death in people with heart disease who are also overweight or obese.
“We know that treating obesity is more than just a number on a scale,” a spokesperson for Novo Nordisk said. The company continues to explore other potential benefits of semaglutide, the active ingredient in Wegovy, including its possible uses in treating Alzheimer’s and liver diseases.
Meanwhile, Lilly is conducting studies on tirzepatide, the active ingredient in Zepbound, to assess its effects on heart failure, sleep apnea, and diabetes prevention. The company plans to release additional findings at a medical conference next year.
Both companies are also working on oral versions of their injectable medications, which could make treatment more accessible for patients in the future.
