Weight Loss Drug Maintains Dramatic Results for Three Years Straight – ScienceBlog.com

Some participants lost nearly a third of their body weight and kept it off for three years with tirzepatide, according to groundbreaking long-term data presented at the European Congress on Obesity this week.

While most weight loss methods see results fade over time, researchers found that weekly injections of tirzepatide — marketed as Zepbound in the US and Mounjaro in the EU — produced sustained weight reduction in people with obesity or overweight who don’t have diabetes.

“Our long-term analysis of tirzepatide establishes that clinically relevant weight loss can be sustained for up to 3 years in a diverse population of adults with overweight or obesity but not diabetes, regardless of age, BMI, and duration of obesity at the outset of the study,” said Dr. Luca Busetto from the University of Padova in Italy, who led the research team.

The findings extend earlier results from the SURMOUNT-1 clinical trial, which initially reported 15-21% weight loss after 72 weeks of treatment. This latest analysis followed 700 participants for a full three years, revealing three distinct patterns of weight loss.

The most responsive group — predominantly female and without obesity-related medical complications — lost approximately 30% of their initial body weight. A second group achieved around 20% weight reduction, while a third group maintained roughly 10% weight loss.

“Adults in Group 1 were on average almost 10% lighter than their initial body weight after 3 years. Whereas participants in Group 3, with the highest proportion of females and those with no medical conditions linked to obesity, lost another 20%, so their overall average weight loss was about 31%,” Dr. Busetto explained.

These results stand in sharp contrast to traditional weight loss methods, which typically produce short-lived results. Even modest weight reduction can yield significant health benefits — losing just 5% of body weight reduces diabetes risk and improves blood pressure and cholesterol levels.

Tirzepatide works by mimicking two hormones naturally produced after eating — GLP-1 and GIP — which regulate insulin production, slow stomach emptying, and signal fullness to the brain. The medication received FDA approval in November 2023 and European approval in June 2024 for weight management in adults with obesity or overweight who have at least one weight-related condition.

Despite the impressive results, researchers noted that everyone eventually reaches a weight loss plateau. “Everyone hits a weight loss plateau at some point, no matter which weight loss intervention they use,” explained Dr. Busetto. “GLP-1 and GIP are just two of eight hormones that control hunger and weight, and eventually, the other hormones signal the body’s protective mechanisms to make changes to prevent more weight loss.”

The timing of this plateau varied significantly between groups. Most participants in the lowest and middle weight loss groups plateaued around 24 weeks, while those in the highest-responding group continued losing weight for 36-48 weeks before stabilizing.

Dr. Busetto emphasized that “losing 15% of body weight is the sweet spot at which people tend to reap most health benefits,” adding that these findings could help physicians develop more personalized treatment approaches.

Like other medications in its class, tirzepatide commonly causes gastrointestinal side effects. The most frequently reported in the trial were nausea, diarrhea, and constipation, with no new safety concerns identified during the extended follow-up period.

As obesity rates continue to climb worldwide, these results offer promise for long-term management of what many health organizations now recognize as a chronic disease requiring ongoing treatment.

“The findings could provide deeper insights into the efficacy of tirzepatide across different demographics and medical histories, potentially allowing for more individualised treatment plans and goals,” Dr. Busetto concluded.