Tirzepatide vs. Semaglutide: Which Is Better for Weight Loss?
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Losing weight and keeping it off is a challenge for many people. While diet and exercise are important, they’re often not enough—especially for those with obesity. That’s where new medications like tirzepatide and semaglutide come in. A recent head-to-head clinical trial compared these two powerful treatments to see which works better.
What Are Tirzepatide and Semaglutide?
Both drugs are weekly injections that help with weight loss by reducing appetite and improving how the body uses energy. Semaglutide (brand name Wegovy) targets one hormone called GLP-1. Tirzepatide (brand name Zepbound) targets two hormones—GLP-1 and another called GIP.
Because tirzepatide acts on two pathways, scientists believe it may lead to greater weight loss. This new trial, called SURMOUNT-5, tested that theory.
Who Was in the Study?
The trial included 750 adults with obesity, but none had diabetes. Everyone either had a body mass index (BMI) over 30, or over 27 with a health condition related to obesity (like high blood pressure or sleep apnea).
Participants were randomly assigned to take either tirzepatide (10 or 15 mg) or semaglutide (1.7 or 2.4 mg) once a week for 72 weeks—that’s nearly a year and a half. All participants also received advice on healthy eating and exercise.
What Were the Results?
The results were clear: tirzepatide led to more weight loss.
- People on tirzepatide lost an average of 20.2% of their body weight.
- People on semaglutide lost 13.7%.
- On average, that’s about 22.8 kg (50 lbs) with tirzepatide and 15 kg (33 lbs) with semaglutide.
Even more impressive, nearly 1 in 5 people on tirzepatide lost 30% or more of their weight, compared to just 1 in 15 on semaglutide.
Tirzepatide also reduced waist size more effectively—about 18.4 cm (7.2 inches) versus 13 cm (5.1 inches) with semaglutide.
Health Benefits Beyond Weight Loss
Both medications improved health markers such as:
- Blood pressure
- Blood sugar levels
- Cholesterol
These changes are important because they reduce the risk of heart disease and other obesity-related illnesses. The more weight people lost, the greater the improvements in these health factors.
What About Side Effects?
Both medications caused similar side effects, mostly related to the stomach—nausea, constipation, and diarrhea. These were usually mild and happened during the first few weeks. Semaglutide users were slightly more likely to stop treatment due to side effects.
Some people on tirzepatide had injection-site reactions, but they were not serious.
Which Should You Choose?
Tirzepatide clearly led to more weight loss than semaglutide in this trial. However, both are effective and may be suitable for different people. If you're considering either medication:
- Talk to your doctor about your weight loss goals and medical history.
- Ask about insurance coverage, as costs may vary.
- Consider your side effect tolerance and whether you’re okay with injections.
A New Era in Obesity Treatment
This study is exciting because it shows how much progress has been made in treating obesity. Just a few years ago, losing 5–10% of body weight with medication was considered good. Now, with drugs like tirzepatide, people are losing 20–30%, which can have life-changing health benefits.
But medications aren’t a magic fix. They work best when combined with healthy habits—regular activity, good nutrition, and support from healthcare providers.
Final Thoughts
Obesity is a complex condition that’s hard to manage with willpower alone. New medications like tirzepatide and semaglutide offer real hope. While both help with weight loss, tirzepatide appears to be the stronger option for now.
If you’re struggling with your weight, know that you’re not alone—and that better tools are now available to help you take control of your health.