Mounjaro and Ozempic are both weekly injections that can help with weight loss—and they’re each in pretty high demand.
But they differ in a lot of ways. For one, Ozempic is actually licensed as a treatment for type 2 diabetes, but is sometimes used off-label for weight. Mounjaro is approved for both diabetes and weight loss.
Plus, they’ve each been shown to drive different results, come with separate price tags, and use their own active ingredients. So, which one is best for you? To help you decide, here’s a head-to-head comparison of Mounjaro vs Ozempic for weight loss.
How does Mounjaro work?
Both Mounjaro and Ozempic work by making you feel full, so you eat less.
Mounjaro weight loss injections, which use the active ingredient tirzepatide, do that by acting like two of your body’s natural appetite-suppressing hormones: GLP-1 and GIP. Mimicking these hormones slows down your digestion and helps keep cravings at bay.
How does Ozempic work?
Ozempic slows digestion and suppresses your appetite, too. But it does that by acting like GLP-1 only. So, that makes it a GLP-1 receptor agonist.
Because Ozempic brings on the effects of one hormone, rather than two like Mounjaro, it’s considered the less potent medicine. It still works very well, though! Scroll down the page a bit to learn what sort of results it can drive.
FYI: Semaglutide is the active ingredient in Ozempic.
Is Wegovy the same as Ozempic?
Kind of. Ozempic and Wegovy are two different names for the same medicine. Both are brand names for semaglutide. That means they have the same effect on the body.
The difference is in how each medicine is used. Ozempic is licensed for type 2 diabetes while Wegovy is approved for weight loss. And they’re available in different doses. The highest strength of Ozempic is 2mg, while it’s 2.4mg for Wegovy.
So, if you’re interested in using Ozempic for weight loss, you’ll most likely be prescribed Wegovy instead.
Ozempic vs Mounjaro for weight loss: Which is more effective?
Now for the million-dollar question: Which medicine works better for weight loss? Let’s take a look at what the science says.
Heads up: In this bit we’ll be referring to Ozempic/Wegovy as semaglutide.
According to clinical research, Mounjaro comes out on top. In one trial, those taking Mounjaro lost an average of 25.3% of their starting weight after 88 weeks. That figure aligns with other studies, too. In a 72-week trial, the mean loss in people taking the highest strength of Mounjaro was 22.5%.
With semaglutide, the numbers are slightly lower (but still very impressive!). After 68 weeks of taking the medicine, one study showed that people lost 14.9% of their starting weight on average. An analysis of six clinical trials found that the average weight loss on semaglutide was 11.8% when taking it for up to 104 weeks.
But watch out. While scientific research can give you an idea of how well a medicine works, there’s no way to predict how it will affect you personally. These studies report average results from big groups of people, meaning that some lost more while others lost less.
If your numbers look different to the above—that’s totally fine. You’re on your own journey and you’ll reach your goals when you’re meant to.
What are the side effects of Ozempic vs Mounjaro?
Mounjaro and Ozempic/Wegovy have pretty similar side effects. Mostly, they’re related to the gut and tend to clear up on their own.
Here’s how common Mounjaro vs Ozempic side effects compare:
Very common side effects (affecting more than 1 in 10 people)
Both Ozempic/Wegovy and Mounjaro can cause a range of gastrointestinal symptoms. The most frequently reported side effects include:
- Nausea
- Vomiting
- Constipation
- Stomach pain
- Diarrhoea
Additionally, Ozempic/Wegovy users may also experience:
- Headache
- Feeling weak or tired
Common side effects (affecting up to 1 in 10 people)
These side effects may still occur but are less common:
For both medications:
- Dizziness
- Upset stomach or indigestion
- Burping
- Gas
- Bloating
- Heartburn
- Hair loss
- Gallstones
- Injection site reactions
Ozempic/Wegovy may also cause:
- Gastritis
- Change in how food tastes
Mounjaro may also cause:
- Feeling tired
- Low blood pressure
Side effects support at Voy
"If you're using Voy and you experience any side effects, rest assured that our expert clinicians are just a message or phone call away. They can adjust your dose, prescribe medication to ease your symptoms, or simply offer reassurance.
Everyone responds differently to weight loss treatment and we'll help you find what feels right for you."

What about ‘Ozempic face’?
To give you a quick refresher: this is a term for the gaunt, sunken look some people get in their face after they lose a lot of weight quickly.
But despite its name, ‘Ozempic face’ doesn’t only happen to people taking Ozempic—or any weight loss injection, for that matter. It happens following a rapid drop in weight, however the method.
And actually, with weight loss medicines, the idea is that you lose weight gradually and sustainably over the long term—we’re talking a few percentage points of your body weight per month.
So, if you take your medication as advised and stick to your plan, you may be less likely to experience any gauntness or facial sagging. Though your face might look a bit more angular and slimmed down as you lose weight.
Mounjaro vs Ozempic: Which one is right for you?
This is a decision for you and your provider. They’ll consider your health and medical history, along with your treatment goals, when they make the call.
For example, if you or anyone in your family has ever had a type of thyroid cancer called medullary thyroid carcinoma, it’s not recommended that you use Mounjaro.
And just to reiterate: because of how it’s licensed, your doctor would probably recommend Wegovy over Ozempic for weight loss.
Your weight loss journey
Whether you’re just starting out on your weight loss journey or have been at it for a while—we see you. We know how tough it can be to make changes and stick with them, especially when you aren’t seeing the results you hoped for.
If you can relate to that, weight loss medication might be a great option. When coupled with long-term lifestyle changes, they can help you lose up to 25% of your starting weight after at least a year.
Through our weight loss programme, you’ll work with our team of clinicians and coaches to build lifestyle habits that last—and receive monthly weight loss medication in the post. Our programme is backed by science and designed to drive sustainable, long-term results.
You can take your next step right now. Take our quiz to see if you’re eligible for the programme. Our clinicians will review your answers and come back to you right away.