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Scott Weaver
Updated at: October 21, 2025 · 10 min read
What is Retatrutide?: Beginner's Guide To 'Triple G'
Retatrutide, also known as Triple G, is generating attention as a potential new treatment for weight loss and related health conditions. Developed by Eli Lilly, this experimental drug targets multiple pathways in the body, setting it apart from other medications currently available. Although not yet approved in the UK, it is being discussed for its promising clinical trial results and potential benefits.
In this guide, we explore what retatrutide is, how it works, what it's used for, how it compares with other treatments and what to expect in terms of availability, safety and cost.
Key Takeaways
Here are the five biggest takeaways from this article about Retatrutide (Triple G):
Retatrutide is a potential weight loss medication that targets three hormonal pathways involved in appetite and metabolism.
Early clinical trials have shown significant weight loss in participants, with some losing over 30% of their body weight.
It is administered via a weekly subcutaneous injection using a pen.
Retatrutide is not yet available in the UK, with phase III trial results expected in 2026.
Existing medications like Mounjaro and Wegovy remain safe and effective options, available through UK Meds.
What is retatrutide?
Retatrutide, often referred to as Triple G, is a new medication developed by Eli Lilly. It belongs to a class of drugs known as GLP-1 receptor agonists, but it goes further by also targeting GIP (glucose-dependent insulinotropic polypeptide) and glucagon receptors. This triple-action mechanism is designed to help regulate appetite, improve glucose control and promote fat breakdown [2].
Unlike older medications that focus on a single pathway, retatrutide combines multiple effects to provide a more comprehensive approach to weight loss and management. This may make it more effective in supporting long-term weight loss and metabolic health.
Video: The Key Facts To Know About Retatrutide
In the short explainer video below Prof. Donal O Shea, specialist doctor in endocrinology and obesity management, explains the key things to know about retatrutide.
Who can use it?
As of now, retatrutide is NOT approved for human use. If approved, it is expected to be suitable for adults living with obesity or who are overweight with at least one weight-related health condition. This could include high blood pressure, type 2 diabetes or high cholesterol.
It is likely to be prescribed alongside lifestyle changes such as dietary improvements and increased physical activity. As with other medications in this class, not everyone will be eligible. A full assessment will be required to determine suitability based on individual health status and medical history.
What does Retatrutide treat?
Retatrutide is a new treatment that has mainly been developed to support weight loss in people living with obesity. Early research suggests that it could be a highly effective option for helping people manage their weight [2].
Alongside its use for weight loss, Retatrutide is also being studied as a possible treatment for type 2 diabetes. Type 2 diabetes happens when the body doesn’t make enough insulin or when insulin doesn’t work properly [5]. This leads to high blood sugar levels, which can make people feel tired and thirsty, need to urinate more often, or lose weight without trying [5]. Some may also notice blurred vision, slower healing of cuts or wounds, or recurring thrush and itching around the genitals [5].
Because Retatrutide targets glucagon receptors, it helps improve insulin sensitivity and lower blood sugar levels. This means it could become an effective treatment option for people with type 2 diabetes, helping to manage both blood sugar control and body weight [2].
Researchers are also exploring how Retatrutide might help with non-alcoholic fatty liver disease (NAFLD). This condition develops when too much fat builds up in the liver and is not caused by alcohol [6]. It’s often linked to being overweight, living with obesity, or having type 2 diabetes. If NAFLD progresses, it can lead to inflammation, scarring, or even liver failure [6].
Because Retatrutide may help reduce liver fat in people with obesity, it could also help slow or prevent the progression of NAFLD in the future. Studies are ongoing to better understand these potential benefits [5].
How to administer Retatrutide
It is expected that Retatrutide would be given as an injection once a week just under the skin into your arm, thigh, or stomach, just like other injection pen treatments of a similar nature.
It works in a similar way to other GLP-1 medications such as Wegovy and Mounjaro. When it becomes available, it is expected to come in an easy-to-use pre-filled pen. You would simply attach a new needle before each injection and follow the instructions provided.
What are the potential side effects of retatrutide?
Retatrutide side effects appear to be similar to those seen with other GLP-1 medicines such as Wegovy and Mounjaro. In clinical trials [2], the most common side effects were mild digestive issues, including:
nausea
diarrhoea
vomiting
constipation
These symptoms were dose-related, usually mild to moderate, and often improved when the dose was increased more slowly.
Some participants experienced a small, temporary increase in resting heart rate, which typically peaked around week 24 before settling again. This rise was similar to what has been observed with other GLP-1 receptor agonists and is not thought to pose a safety risk.
Other mild side effects included altered skin sensations, such as tingling or prickling. These were generally short-lived and did not cause people to stop treatment.
The likelihood of side effects increased with higher doses. They were more common in people taking 8 mg or 12 mg of Retatrutide compared with lower doses, and more frequent in those who started treatment at 4 mg rather than 2 mg.
Early research suggests that Retatrutide has a safety profile similar to existing GLP-1 medicines. Digestive symptoms are the most common side effects, but they are usually mild and can often be managed by gradually increasing the dose.
When will retatrutide be available in the UK?
Although early trial results are encouraging, retatrutide is not yet approved for use in the UK or elsewhere. It is still undergoing clinical evaluation, with the current phase III trials expected to be completed in May 2026. These large-scale studies will help confirm the drug’s safety and effectiveness across a broader population.
After the trial results are released, authorities such as the Medicines and Healthcare products Regulatory Agency (MHRA) and the National Institute for Health and Care Excellence (NICE) will assess whether to approve the treatment for UK use.
How much will retatrutide cost?
At this stage, there is no confirmed price for retatrutide in the UK. However, it is likely to be priced similarly to other advanced weight loss medications such as Wegovy (semaglutide) and Mounjaro (tirzepatide). The final price will depend on factors such as dosage, strength and manufacturer pricing.
Currently, the starting cost of injectable treatments like Wegovy and Mounjaro is typically between £115 and £150, depending on the dose and supplier.
Retatrutide vs. Other Weight Loss Medications
Retatrutide is being closely compared with other well-established weight loss medications like Mounjaro and Wegovy. Both of these are currently available in the UK and have helped many people achieve significant results.
Mounjaro works by activating GLP-1 and GIP receptors, while Wegovy only targets the GLP-1 pathway. Retatrutide, by activating GLP-1, GIP and glucagon receptors, may offer an even more effective solution by promoting appetite reduction, fat breakdown and improved blood sugar control.
Early data suggests that retatrutide could surpass both Mounjaro and Wegovy in terms of weight loss results, though longer-term data is still needed to confirm this.
Is Retatrutide better than Wegovy and Mounjaro? What The Research Tells Us
At the moment, Wegovy and Mounjaro are two of the most well-known injectable treatments available for supporting weight loss. Both have been shown to help people living with obesity lose a significant amount of weight when combined with healthy lifestyle changes.
Why is retatrutide nicknamed 'Triple G'?
Wegovy works by targeting a hormone called GLP-1, while Mounjaro targets both GLP-1 and GIP. Retatrutide, however, goes a step further. It targets three key receptors: GLP-1, GIP, and glucagon receptors. This triple action may make it more powerful at helping people lose weight compared to Wegovy and Mounjaro - this is how it's earned the nickname of 'Triple G'.
Retatrutide Clinical Trials
Retatrutide is currently in phase III clinical trials, which are the final step before potential approval. These trials aim to confirm the drug’s effectiveness and safety in large groups of people.
The phase III trial is scheduled to conclude in May 2026, with full results expected later that year. These findings will be critical in determining whether retatrutide is approved for use in the UK [1] [2] [3] [4].
Clinical studies have already shown that Retatrutide can lead to greater and faster weight loss. In one study, participants taking Retatrutide lost an average of 24% of their body weight in 48 weeks [2]. More than one in four participants lost over 30% of their initial weight. These results are among the highest reported in weight loss drug trials so far. This is currently the highest level of weight loss ever recorded in a clinical trial for an obesity treatment.
By comparison, longer-term studies have found that Mounjaro users lost around 22% of their body weight after 72 weeks, and Wegovy users achieved around 17% weight loss over the same period [7]. Another emerging treatment, CagriSema, has shown about 23% weight loss in 68 weeks [8]. These results suggest that Retatrutide could become one of the most effective medical treatments for obesity once approved.
Your Weight Loss Journey
Everyone’s weight loss journey is different. What works well for one person may not be the right choice for another. While retatrutide is not yet available, there are already safe and effective options that can be prescribed today, including Mounjaro and Wegovy.
At UK Meds, all prescription requests are subject to an online clinical consultation. This ensures the treatment is only supplied if it is considered safe and appropriate by a qualified independent prescriber.
Making steady, sustainable progress is key. Weight loss is most successful when combined with good nutrition, regular movement and the right professional support.
Final Thoughts
Retatrutide could be a major development in the world of weight loss treatments, offering a triple-action approach that may outperform existing medicines. Its ability to target multiple hormones involved in hunger and metabolism makes it a promising potential option.
However, it is still being studied and will not be available until the final clinical trial results are complete. In the meantime, trusted medications like Mounjaro and Wegovy remain ideal for people looking to manage their weight. Always seek professional guidance before starting any new treatment.
Sources
[4] Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial - PubMed
Blog author
Scott Weaver
Scott is an experienced and professional content writer who works exclusively for UK Meds.
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