People using the weight-loss drug Mounjaro have kept off a large amount of weight for up to three years, according to new clinical trial data. The findings come from a long-term study called Surmount-1, which tracked nearly 700 adults with obesity or pre-diabetes. Researchers found that most participants continued to lose weight or maintain their weight loss over time. The study highlights the power of tirzepatide, the drug in Mounjaro, and may help guide future obesity treatments.
Mounjaro: A Powerful Tool for Long-Term Weight Loss
Mounjaro, often called the “King Kong” of weight-loss drugs, is a weekly injection. It contains tirzepatide, a drug that mimics hormones involved in blood sugar and appetite control. The latest results come from a study running for over 176 weeks (about three years), conducted by Eli Lilly and academic partners.
All 700 participants were overweight or obese and had signs of pre-diabetes. The study grouped them by how they lost weight:
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Gradual group: 9.2% average body weight loss
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Moderate group: 20.2% average weight loss
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Rapid group: 30.8% average weight loss
Each group made up roughly one-third of the participants.
Weight Loss Patterns and Plateaus
Researchers noticed that people followed different paths. Some lost weight slowly and steadily. Others lost it fast but reached a plateau sooner. Those who lost weight more slowly kept shedding pounds for a longer time.
On average, people hit their lowest weight after 22 months, losing about 23.1% of their body weight. By the end of the study, the average weight loss stayed at 19.4%, showing only a small amount of regain.
Importantly, 70% of participants gained back less than 5% of their original weight after hitting their lowest point.
Expert Reactions and Clinical Value
Experts believe these results are important for doctors and patients. According to Prof Luca Busetto of the University of Padova, early response to Mounjaro could help doctors predict long-term success. He emphasized that most people kept off a meaningful amount of weight.
Prof Naveed Sattar from the University of Glasgow added that early weight loss patterns may guide which patients need more support or stronger treatments. It could also help set realistic goals from the beginning.
Dr Simon Cork from Anglia Ruskin University called the findings a “game-changer.” He said the drug’s long-term effect could help reduce cases of type 2 diabetes, high blood pressure, and other health risks linked to obesity.
Ongoing Debate Over Long-Term Use and Advertising
Even with promising results, rules around these drugs remain strict. In the UK, health authorities have reminded clinics and businesses that they cannot advertise Mounjaro, Wegovy, or Saxenda directly to the public. This includes:
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Social media posts
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Influencer content
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Search engine ads
The Advertising Standards Authority, the MHRA, and the General Pharmaceutical Council have all warned that such promotions are against the law. These reminders follow past investigations into unsafe marketing practices on platforms like Instagram, TikTok, and Google.
A Step Forward for Obesity Care
As obesity becomes more common, experts say drugs like Mounjaro may offer hope to many. But the full benefits will only be seen if people use them safely and under medical guidance. The Surmount-1 study’s findings will be presented at the European Congress on Obesity in Málaga next month. More long-term data is expected in the future.