Over the past few years, two injectable medications — semaglutide (sold as Ozempic) and tirzepatide (sold as Mounjaro) — have attracted huge attention for their role in weight loss and blood sugar control. Originally developed for type 2 diabetes, both drugs are now being used by people looking to shed significant weight, whether or not they have diabetes.

But how do these medications actually work? And what’s the difference between them?

Here’s a breakdown of what you should know if you’re considering one of these treatments.

What Is Semaglutide (Ozempic)?

Semaglutide is a GLP-1 receptor agonist. That’s short for “glucagon-like peptide-1.” In plain terms, it’s a hormone your body already makes — and semaglutide mimics its effects. It helps lower blood sugar, slows how quickly your stomach empties, and reduces appetite. The result: people feel full faster and stay full longer.

Ozempic was originally approved to help manage type 2 diabetes. But when doctors noticed that patients were losing weight, it led to further research. A higher-dose version called Wegovy is now approved specifically for chronic weight management.

People take Ozempic once a week via injection, usually in the abdomen, thigh, or upper arm.

What Is Tirzepatide (Mounjaro)?

Tirzepatide is a newer drug. Like semaglutide, it’s also used to treat type 2 diabetes. But tirzepatide goes a step further — it acts on two hormone receptors instead of just one.

It mimics both GLP-1 and GIP (glucose-dependent insulinotropic polypeptide). This dual action seems to lead to even more appetite suppression and better blood sugar control.

Studies show that patients using Mounjaro often lose more weight, and faster, than those using semaglutide. Some people on tirzepatide lose over 20% of their body weight — numbers previously seen only with bariatric surgery.

Like Ozempic, Mounjaro is taken once a week through a small injection.

How Are They Similar?

  • Both are injectables: You use them once a week with a pen-like device.

  • Both help with weight loss and blood sugar: They slow digestion and reduce hunger.

  • Both can cause side effects: Most commonly nausea, vomiting, constipation, or diarrhea. These usually improve over time.

What’s the Main Difference?

The biggest difference is in how many hormone systems they target.

  • Semaglutide targets GLP-1 only.

  • Tirzepatide targets both GLP-1 and GIP.

That extra GIP component may be why people lose more weight on Mounjaro. Some patients who didn’t respond well to semaglutide saw better results after switching to tirzepatide.

There’s also a difference in approval. While Ozempic is approved for diabetes and Wegovy is approved for obesity, Mounjaro is currently approved only for type 2 diabetes in many countries. However, the FDA in the U.S. has approved Zepbound, a weight loss version of tirzepatide.

Which One Is Right for You?

It depends on your health goals. If you’re managing diabetes and want to lose some weight, both are great options. If weight loss is your main goal and you don’t have diabetes, a version like Wegovy or Zepbound might be more suitable, depending on what your doctor prescribes.

Keep in mind: these medications aren’t magic. They work best when combined with changes in eating habits and physical activity. But they can be a huge help in kickstarting progress — especially for people who have struggled to lose weight through diet alone.

Cost and availability are also major factors. These medications are expensive and not always covered by insurance. Some people switch between brands based on price, availability, or personal response.

Are There Any Risks?

Serious side effects are rare, but possible. There’s a small risk of thyroid tumors, which is why people with a history of medullary thyroid cancer should avoid them. There’s also a risk of low blood sugar, especially if taken with insulin or other diabetes meds.

That’s why these drugs should only be used under medical supervision, with regular follow-ups.

Frequently Asked Questions

What are the main benefits of Ozempic and Mounjaro?

Both help with blood sugar control and weight loss. They reduce hunger, slow digestion, and help you feel fuller for longer — leading to lower calorie intake and gradual weight loss.

Is one better for weight loss than the other?

So far, research suggests that tirzepatide (Mounjaro) may lead to slightly more weight loss than semaglutide (Ozempic or Wegovy). But individual results vary, and some people respond better to one than the other.

Do I need to have diabetes to use these medications?

No. While Ozempic and Mounjaro were developed for diabetes, versions like Wegovy and Zepbound are approved for weight loss in people without diabetes.

Are these drugs safe to take long-term?

Most studies show they’re safe for long-term use, but they need to be monitored by a healthcare provider. Regular blood work and check-ins are important to watch for side effects and adjust doses.

Will I regain weight if I stop taking them?

Possibly. Many people regain some weight after stopping. That’s why it’s important to combine medication with lasting lifestyle changes — like healthier eating, exercise, and stress management.