If you’ve been researching weight loss medications recently, you’ve almost certainly come across both the names Mounjaro and more recently, Retatrutide. Mounjaro has already transformed the lives of thousands of people around the world, while Retatrutide is generating huge amounts of excitement despite not even being available yet!
It’s easy to see why people are asking questions like: Is Retatrutide better than Mounjaro? Does it help you lose more weight? Should you wait for Retatrutide instead of starting Mounjaro? The truth is, there isn’t a simple answer to any of these questions.
Both medications are designed to help with weight loss, but they work in slightly different ways. While early research suggests Retatrutide could produce even greater weight loss than Mounjaro, it’s important to remember that it is still being studied and isn’t yet approved for general use.
I’ve spent a long time researching both of these medications, and with that knowledge, I’ll explain the differences between Retatrutide and Mounjaro, how they work, what the clinical trials have shown so far, and whether one really appears to have an advantage over the other.
As always, before undertaking any kind of weight loss or lifestyle change, it is always best to speak to a medical professional or registered dietician who is best suited to give personalised advice on your individual health needs and health issues. This blog post has been researched to the best of my ability, and the information posted is accurate at the time of publication. Soph-obsessed is not affiliated in any way with any weight loss plan. Retatrutide and other peptides are currently in the early stages of research and not approved for use in humans. Please make sure that any research you read here is checked for accuracy.
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Retatrutide vs Mounjaro: Biggest Differences
Which Helps You Lose More Weight?
Should You Wait for Retatrutide?
What Is Mounjaro?
Mounjaro is the brand name for the medication tirzepatide. It’s a once-weekly injection that was originally developed to help people with type 2 diabetes, but it quickly became clear that it also led to significant weight loss. Unlike older weight loss medications that target just one hormone, Mounjaro works by activating two naturally occurring hormone receptors in your body.
These are:
- GLP-1 (Glucagon-Like Peptide-1)
- GIP (Glucose-Dependent Insulinotropic Polypeptide)
Together, these hormones help regulate the appetite, improve blood sugar control, slow the rate at which food leaves your stomach and help you feel fuller for longer. For many people, this results in eating less without constantly feeling hungry. People also report the quieting of food noise.
Mounjaro has already become one of the most effective weight loss medications currently available and is now prescribed in many countries for obesity as well as type 2 diabetes.
You might be interested in:What Happens When You Stop Mounjaro?
What Is Retatrutide?
Retatrutide is one of the newest weight loss medications currently being developed, and it’s already attracting plenty of attention. Although it isn’t available to the public yet, the results from early clinical trials have been impressive enough for many people to wonder whether it could eventually become even more effective than Mounjaro.
Just like Mounjaro, Retatrutide is a once-weekly injection that you would do at home, but it has one major difference. Instead of targeting two hormone receptors like Mounjaro, Retatrutide targets three.
It works by activating:
- GLP-1 (Glucagon-Like Peptide-1)
- GIP (Glucose-Dependent Insulinotropic Polypeptide)
- Glucagon receptors
This is why you’ll often hear Retatrutide described as a triple agonist.
The GLP-1 and GIP receptors work in a very similar way to that of Mounjaro by helping to reduce appetite, improve blood sugar regulation and increase feelings of fullness. The extra glucagon receptor is what makes Retatrutide unique and quite exciting overall.
Although the word “glucagon” might sound confusing, researchers believe activating this receptor may encourage the body to use more energy, increasing calorie expenditure alongside reducing appetite. In simple terms, while you’re naturally eating less, your body may also be burning more calories. Which has to be said is pretty impressive if that is how it works!
This is one of the reasons scientists are so excited about Retatrutide, and I completely agree. It’s important to take a moment and remember that at the time of this article, Retatrutide is still being studied in Phase 3 clinical trials. While the early data looks incredibly promising, it hasn’t yet received regulatory approval for weight management, so it isn’t something your GP or weight loss clinic can routinely prescribe at the moment. It may be that as additional tests and trials are concluded its deemed Retatrutide isn’t safe to come to market. At the moment, it is too early to say.
Retatrutide vs Mounjaro: The Biggest Differences
Although Retatrutide and Mounjaro have a lot in common, its important to know that they’re not the same medication. Both are designed to help people lose weight by reducing appetite and improving the way the body regulates blood sugar, but Retatrutide has an additional mechanism that researchers hope could make it even more effective.
Here’s a side-by-side comparison.
| Feature | Mounjaro | Retatrutide |
|---|---|---|
| Active ingredient | Tirzepatide | Retatrutide |
| Weekly injection | Yes | Yes |
| Hormones targeted | GLP-1 and GIP | GLP-1, GIP and glucagon |
| How many receptors? | Two | Three |
| Approved for use? | Yes (in many countries) | No – currently in Phase 3 clinical trials |
| Main effect | Reduces appetite and improves blood sugar control | Reduces appetite, improves blood sugar control and may increase energy expenditure |
| Average weight loss seen in clinical trials | Around 20-22% | Around 24% in Phase 2 trials, with Phase 3 results showing averages above 28% in some study populations, although the studies cannot be directly compared at the moment. |
It’s quite easy to look at this table and understand why so many people are excited about Retatrutide. On paper, it appears to offer everything Mounjaro does, with the added benefit of activating the glucagon receptor, which researchers believe may encourage the body to burn more energy. I mean, who doesn’t want that?
However, this is where it’s important not to jump the gun.
The clinical trials for Retatrutide and Mounjaro were carried out at different times, with different groups of participants and different study designs. That means you can’t simply compare the headline weight loss figures and declare one medication the winner. At the moment, there hasn’t been a large head-to-head clinical trial comparing the two directly, so we don’t yet know exactly how much of a difference there really is.
For now, Mounjaro remains the most effective weight loss medication that’s widely available, while Retatrutide is shaping up to be one of the most exciting treatments currently in development.
Related Post: When Will Retatrutide Be Available? Latest UK Approval Timeline (2026)
How Do Retatrutide and Mounjaro Work?
At first glance, Retatrutide and Mounjaro seem very similar. They’re both once-weekly injections, they’re both designed to help with obesity and weight management, and they both work by mimicking hormones that your body naturally produces after you eat. Those hormones send signals to your brain to tell you that you’re full, help regulate blood sugar levels and influence how your body uses energy.
How Mounjaro Works
Mounjaro works by activating two hormone receptors: GLP-1 and GIP.
Without getting too scientific, these hormones help to:
- Reduce your appetite
- Help you feel fuller for longer after meals
- Slow down how quickly your stomach empties
- Improve blood sugar regulation
- Reduce food cravings for many people
For lots of people taking Mounjaro, one of the biggest changes is something often referred to as “food noise.” The constant thoughts about food can become much quieter, making it easier to stick to a calorie deficit without feeling like you’re relying on willpower alone. Of course, everyone’s experience is different, but this reduction in appetite is one of the main reasons Mounjaro has been so successful across the board.
How Retatrutide Works
Retatrutide does everything Mounjaro does, but with one important difference. Alongside GLP-1 and GIP, it also activates the glucagon receptor. That extra receptor is thought to increase the amount of energy your body uses throughout the day. In other words, while the GLP-1 and GIP hormones help you eat less, the glucagon receptor may encourage your body to burn more calories at the same time. Which is on the whole rather impressive!
Researchers believe this combination could explain why Retatrutide has produced such impressive weight loss results in its clinical trials. That doesn’t mean it’s a miracle drug, though. People taking part in the studies were also encouraged to follow a reduced-calorie diet and increase their physical activity. Like Mounjaro, Retatrutide works best alongside healthy lifestyle changes rather than replacing them. These types of medications are a tool in the arsenal rather than a magic wand or quick fix!
Which Works Better?
This is the million-pound question, and at the moment and honestly, nobody can answer it with complete certainty. Retatrutide certainly has an exciting mechanism of action in theory, and the early trial results suggest it could eventually outperform Mounjaro when it comes to average weight loss. However, because the two medications haven’t been directly compared in the same large clinical trial, it’s impossible to say exactly how much better it may be, or whether it will prove superior for everyone. It would be unfair to make assumptions at this point.
The important thing to remember is that both medications aim to tackle weight management in a more biological way. Rather than relying purely on willpower, they’re designed to help regulate the hormones that influence hunger, fullness and energy balance.
And for many people, that’s a complete game changer.
Which Helps You Lose More Weight?
If you only looked at the headlines, you’d probably think Retatrutide is the clear winner in this category. We can see from the early clinical trials some remarkable results, with participants losing, on average, more weight than we’ve seen with any currently approved medication. It’s no surprise that many people are calling it the next big breakthrough in obesity treatment. But in true Soph-obsessed style, it’s important to dig a little deeper than the headline figures.
Mounjaro’s Weight Loss Results
Mounjaro has already proven itself in large clinical trials and, perhaps even more importantly, in real-world use. Throw a stone, and you will hit someone on Mounjaro. It has transformed the weight loss industry as we know it and created a shrinking world we have never seen before!
In the SURMOUNT-1 trial, adults with obesity or overweight lost an average of around 20% of their body weight over 72 weeks when taking the highest dose alongside diet and exercise. That’s an extraordinary result and one of the reasons Mounjaro has become such a popular treatment for weight management. For someone weighing 100kg, that could equate to around 20kg of weight loss!
Retatrutide’s Weight Loss Results
Retatrutide has also delivered extremely encouraging results. In its Phase 2 trial, participants receiving the highest dose lost an average of 24.2% of their body weight after 48 weeks. More recently, Phase 3 trial results have reported average weight loss of over 28% in some study populations after a longer treatment period. Those numbers are certainly exciting, but they don’t automatically mean Retatrutide is “better.”
Why You Can’t Compare the Numbers Directly
This is something that often gets overlooked online. The studies for Mounjaro and Retatrutide were carried out separately. They involved different groups of people, different study designs and different timelines. Because of that, comparing one percentage with another isn’t comparing like for like. It’s essentially not a fair test. So, until researchers carry out a direct head-to-head trial, nobody can honestly say exactly how much more effective Retatrutide is compared with Mounjaro.
So, Which Comes Out on Top?
Based on the evidence we have today, Retatrutide certainly looks incredibly promising. Its unique triple-action approach may well help some people achieve greater weight loss than Mounjaro, and the clinical trial results suggest it has the potential to become one of the most effective obesity medications ever developed. Which for someone like me who is obsessed with all things under the weight loss industry umbrella is extremely exciting.
However, Mounjaro already has something that Retatrutide doesn’t. It has been prescribed to millions of people, doctors have years of experience using it, and we have a growing body of real-world evidence showing just how effective it can be outside of clinical trials.
So while Retatrutide may eventually take the crown, it simply isn’t possible to say that it has done so yet. It is still possible that Retatrutide may never even make it to market. For now, Mounjaro remains one of the most effective and widely available weight loss medications, while Retatrutide represents an exciting glimpse into what the future of obesity treatment could look like.
Side Effects: Are They Similar?
Whenever a new weight loss medication comes along, one of the first questions people ask is whether it has fewer side effects than the options already available. People want to know what’s safer overall and going to impact their lifestyle the least.
The short answer is that, based on everything we know so far, Retatrutide and Mounjaro have very similar side effect profiles. Which makes sense because they are similar in makeup.
Like Mounjaro, the most commonly reported side effects with Retatrutide are related to the digestive system. This isn’t particularly surprising because both medications work by affecting hormones involved in appetite and digestion.
The most frequently reported side effects include:
- Nausea
- Vomiting
- Diarrhoea
- Constipation
- Stomach pain or discomfort
- Reduced appetite
For most people, these side effects are mild to moderate and tend to be at their worst when starting treatment or increasing to a higher dose. As the body adjusts, many people find that symptoms gradually improve. One thing worth pointing out is that because Retatrutide also activates the glucagon receptor, researchers have been paying close attention to whether this leads to any new or unexpected side effects. So far, the results have been reassuring, with the majority of side effects looking very similar to those already seen with GLP-1 medications like Mounjaro. That doesn’t mean everyone will have the same experience, though. Side effects can manifest at any point which is why this process is so lengthy. Like with anything, some people sail through treatment with very few symptoms, while others find the first few weeks more challenging. Factors such as dose increases, diet, hydration and individual biology can all influence how someone responds.
It’s also important to remember that Retatrutide is still being studied. As larger Phase 3 trials continue and, eventually, if the medication is approved for widespread use, we’ll learn much more about its long-term safety profile and how people respond outside of clinical trial settings.
For now, the evidence suggests that if you’re familiar with the side effects associated with Mounjaro, Retatrutide is unlikely to feel dramatically different from that perspective which is positive.
Should You Wait for Retatrutide?
With all the excitement surrounding Retatrutide, it’s understandable that some people are wondering whether they should hold off starting Mounjaro and simply wait for the newer medication to become available. Personally, I don’t think the answer is as straightforward as that. It’s easy to get caught up in headlines about the “next big thing,” especially when the early results look so impressive. But while researchers continue to study Retatrutide, Mounjaro is already changing lives every single day.
If you’re eligible for Mounjaro now and it’s an appropriate treatment for you, waiting months or even years for another medication may not be the best decision. Losing weight can have a huge impact on your health, confidence and quality of life, and delaying treatment simply because something newer might arrive in the future could mean missing out on those benefits today.
That’s not to say Retatrutide won’t eventually become the preferred option. It may well do. If the ongoing Phase 3 trials continue to produce positive results and regulators approve it, it could become one of the most effective weight loss medications available.
But we’re not there yet, and at this stage it is impossible to say. If you hold off on starting treatment now, you may be disappointed.
At the moment, Retatrutide isn’t routinely available outside clinical trials, and until it completes the approval process, there’s still more to learn about its long-term safety, effectiveness and how it performs in everyday clinical practice.
One thing I’ve learned throughout my own weight loss journey is that there’s always something new just around the corner.
A new diet.
A new medication.
A new programme that’s supposed to be even better than the last.
The reality is that sustainable weight loss isn’t about constantly waiting for the perfect solution. It’s about finding a safe, evidence-based approach that works for you and getting started.
If that’s Mounjaro, there’s absolutely no reason to feel like you’re settling for second best. It’s already one of the most effective weight loss medications available today, backed by robust research and real-world results.
Retatrutide is certainly one to watch, and I’ll be following the latest research closely. But until it’s approved and widely available, Mounjaro remains an excellent option for people who are ready to begin their weight loss journey now.
Final Thoughts
When it comes to Retatrutide vs Mounjaro, it’s easy to see why so many people are comparing the two. Both represent a huge step forward in the treatment of obesity, and both work with your body’s natural hormones to help reduce appetite and support weight loss.
At the moment, though, they’re at very different stages.
Mounjaro is already available in many countries, supported by large clinical trials and growing real-world evidence. It has helped countless people lose significant amounts of weight and improve their health, making it one of the most effective treatments currently available. For the most part, it is considered safe and readily available.
Retatrutide, on the other hand, is still making its way through the clinical trial process. The results so far have been incredibly encouraging, and it has the potential to become one of the most effective weight loss medications we’ve ever seen. But until it’s approved and more long-term data becomes available, there’s still plenty we don’t know. This is a watch a wait type of scenario.
If you’re trying to decide between the two, the reality is that for most people, there isn’t actually a choice yet. Retatrutide simply isn’t available outside clinical trials, whereas Mounjaro is already helping people make meaningful, lasting changes to their health.
As more research is published, I’ll continue updating this article so you have the latest evidence in one place. The science around obesity treatment is moving incredibly quickly, and Retatrutide is definitely one to keep an eye on over the coming years.
Frequently Asked Questions
Is Retatrutide better than Mounjaro?
Retatrutide has shown extremely promising results in its clinical trials so far and may eventually prove to be more effective than Mounjaro for weight loss. However, the two medications haven’t yet been directly compared in the same large clinical trial, so it’s too early to say definitively that one is better than the other.
Can I switch from Mounjaro to Retatrutide?
At the moment, most people can’t. Retatrutide is still undergoing clinical trials and isn’t routinely available outside research settings. If it receives approval in the future, your healthcare provider will be able to advise whether switching is appropriate.
Is Retatrutide approved?
Not yet. Retatrutide is currently in Phase 3 clinical trials. It has not yet received approval for routine prescribing, although researchers are optimistic based on the results seen so far.
Does Retatrutide help you lose more weight than Mounjaro?
Early studies suggest Retatrutide may produce greater average weight loss than Mounjaro. However, because the studies were carried out separately, the results can’t be directly compared. More research is needed before we know exactly how the two medications compare. Weight loss is very much a case-by-case basis.
Why does Retatrutide have three hormone targets?
Unlike Mounjaro, which targets GLP-1 and GIP, Retatrutide also activates the glucagon receptor. Researchers believe this additional action may increase the body’s energy expenditure, which could contribute to the greater weight loss seen in early clinical trials.
Should I wait for Retatrutide instead of starting Mounjaro?
That depends on your individual circumstances, but for many people, waiting isn’t likely to be the best option. Mounjaro is already an effective, evidence-based treatment that’s available now, whereas Retatrutide is still being studied and may not be widely available for some time.
When will Retatrutide be available?
There’s no confirmed release date yet so it is impossible to speculate. Approval depends on the outcome of ongoing Phase 3 clinical trials and decisions made by medicines regulators. If everything continues to go well, it’s expected that applications for approval will follow the completion of those studies.
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