Rybelsus vs. Mounjaro® For Weight Loss

Effectiveness of Rybelsus vs. Mounjaro

Mounjaro is an injectable medication prescribed for type 2 diabetes (1). Mounjaro’s active ingredient, tirzepatide, is also FDA-approved as a weight loss medication under the name Zepbound® (2). Rybelsus is a medication approved by the FDA in 2019 for the treatment of type 2 diabetes. While not formally FDA-approved for weight loss, it is often used “off-label” to help patients lose weight. Its active ingredient, semaglutide, is approved for obesity management as an injectable medication under the brand name Wegovy.

For Mounjaro®, the SURMOUNT-1 trial published in 2022 was a large phase 3 clinical trial with over 2500 participants that looked at how effective Mounjaro® (tirzepatide) was at managing obesity (1). Mounjaro® was given at different doses for a period of 72 weeks to groups of non-diabetic participants who were struggling with obesity. The participants were also enrolled in a calorie restriction diet (500 kcal/day), did 150 minutes of exercise per week, and had regularly scheduled with a dietician (3).

They found that after 72 weeks, each group that was taking Mounjaro® showed significant weight loss compared to the placebo group. Each treatment group experienced a 15-20% change in weight from the start of the trial, with higher doses showing a greater change. This was compared to the placebo group, which only experienced a 3% change in weight. This showed us that the use of Mounjaro® in combination with diet and exercise is very effective at treating obesity.

Though there are no current trials examining Rybelsus in managing obesity, there are studies in diabetic patients that show its effect on weight loss. The PIONEER-1 trial was a phase 3 randomized control trial published in 2019 that examined how well Rybelsus managed diabetes in type 2 diabetics compared to a placebo (2). Rybelsus was given to participants for a period of 26 weeks at different doses (4).

They found that there was a significant difference in body weight in the treatment group receiving a 14 mg dosage of Rybelsus. This group experienced a 2.6 kg (~5lb) difference after just 26 weeks. It should also be noted that the treatment group was not on a diet plan, exercising around 150 minutes per week, nor were they followed by a dietician. This may tell us that there may be an even more significant effect of Rybelsus in combination with diet and exercise for a period of time similar to the SURMOUNT trial. It might even be just as effective!