Blockbuster weight loss drugs like Ozempic might not work as well as advertised, a bombshell study reveals. 

A study by the Cleveland Clinic revealed that patients using semaglutide and tirzepatide—the active components in Ozempic, Wegovy, and Mounjaro—experienced up to 50 percent less weight loss than the figures reported by drug companies in clinical trials.

They were also 40 percent more likely to go off the drugs within a year than patients in trials for reasons such as side effects being too severe.

In the new study, researchers looked at nearly 8,000 obese Americans who were prescribed either semaglutide or tirzepatide for a year. 

One in five stopped taking the drugs within three months and nearly one in three stopped before the end of the year.  

Patients in the new study lost anywhere from four to 12 percent of their body weight in a year depending on how long they stayed on the drugs.

But in the drugs’ clinical trials, they lost between 15 and 21 percent of their weight. 

Researchers suggested this discrepancy might stem from a higher rate of patients discontinuing the drugs and the use of lower doses compared to those administered in clinical trials.

Patients also complained of high drug costs and harsh side effects, which have included stomach paralysis and blindness in severe cases.  

Reality stars Golnesa ‘GG’ Gharachedaghi (left) and Dolores Catania have both admitted to using weight loss drugs

About one in eight Americans report taking weight loss drugs like Ozempic or Wegovy at some point in their lives (file photo)

Dr. Hamlet Gasoyan, the lead author of the study and a researcher at Cleveland Clinic’s Center for Value-Based Care, stated: ‘Our research demonstrates that individuals treated for obesity with semaglutide or tirzepatide typically lost less weight in a standard clinical environment compared to results from randomized clinical trials.’

‘According to our data, this could be explained by higher rates of discontinuation and lower maintenance dosages used in clinical practice, compared to randomized clinical trial settings.’

About one in eight Americans report taking a GLP-1 agonist like Ozempic or Wegovy at some point in their lives. And recent research shows their popularity has soared 600 percent since 2019. 

The study, published Tuesday in Obesity Journal, looked at 7,881 adults patients obese patients using electronic health data.

The majority (6,109) received semaglutide while the remainder took tirzepatide. It’s unclear if they took specific brand names like Ozempic or Wegovy. 

The average participant age was 51 and three in four patients were women. 

Their average body mass index (BMI) was 39, which is considered ‘severe obesity.’ Any BMI over 30 is obese. 

Of those patients, 1,320 had prediabetes, a precursor to type 2 diabetes that affects 100million Americans, most of whom don’t know they have it. 

Participants began taking semaglutide or tirzepatide for obesity between 2021 and 2023. Those that stopped taking the drugs within three months were considered ‘early’ discontinuers and those who stopped in three to 12 months were ‘late’ discontinuers. 

Researchers found about 20 percent of participants stopped taking the GLP-1 drugs early and 32 percent stopped late. 

Additionally, 80 percent were on lower maintenance doses than when they started. This was the equivalent of 1 mg or less of semaglutide or less than 7.5 mg of tirzepatide. 

A maintenence dose is the amount needed to sustain weight loss.  

After one year, people who stopped taking the drug early had a four percent weight reduction compared to seven percent for those who stopped late.

The above graph shows average weight changes over time in participants who took semaglutide or tirzepatide

The above graph shows weight reductions in patients who stopped taking weight loss drugs within three months, in three to 12 months and who never stopped

Those who stayed on the drugs for the full year lost 12 percent, and participants who kept with the drugs and took higher maintenance dosages lost 14 percent body weight on semaglutide and 18 percent on tirzepatide.

In semaglutide and tirzepatide’s clinical trials, patients lost between 15 and 21 percent of their weight after one year, up to 50 percent less than those in the new study who stayed on the drugs for a year. 

The researchers believe participants lost less weight than those in clinical trials promoted by drug companies because they were more likely to stop taking the drugs, hampering their progress. 

They cited clinical trials showing patients discontinued the drugs at a rate of 17 percent, up to 40 percent less often. 

Patients in clinical trials were also more likely to take higher doses. 

Dr Gasoyan said: ‘Our findings about the real-world use patterns of these medications and associated clinical outcomes could inform the decisions of healthcare providers and their patients on the role of treatment discontinuation and maintenance dosage in achieving clinically meaningful weight reductions.’ 

The team found patients most commonly stopped taking weight loss drugs due to high costs, issues with insurance coverage, risk of side effects and medication shortages.