Retatrutide

About Retatrutide 

Retatrutide belongs to a new class of medicines called multi-agonist peptides. Unlike older therapies that target one or two receptors, Retatrutide activates three receptors: GLP-1, GIP, and glucagon. Early research suggests it could deliver greater weight loss than currently approved medications such as Wegovy and Mounjaro.

The fact that it targets three separate pathways means Retatrutide doesn’t just reduce food intake, it also helps the body burn more calories. For people living with obesity and related conditions such as type 2 diabetes, Retatrutide could be a potentially promising candidate.
 

Retatrutide Price

The price of Retatrutide isn’t yet known and will be set when the medication becomes available in the UK. Since Retatrutide is likely to compete with weight loss injections such as Mounjaro and Wegovy, the cost should be similar to those treatments. Currently, Wegovy is considered the most cost-effective treatment compared to Mounjaro.

At Prescription Doctor, the starting price for Wegovy is £129.99, while Mounjaro is £179.99. 

What is Retatrutide Peptide?

Retatrutide is a synthetic peptide developed by the same company behind Mounjaro
(tirzepatide). Peptides are small chains of amino acids that can mimic natural hormones in the body. These hormones are normally released in the gut after eating and play an important role in appetite regulation and energy balance. By mimicking them, Retatrutide helps the body feel fuller, process food more effectively and use stored fat as fuel.

The fact that Retatrutide impacts GLP-1, GIP, and glucagon has earned it the nickname “Triple G”. When it’s released, the treatment will be the first of its kind on the market, making it a promising alternative to available medications.  

Retatrutide works in harmony with existing biological pathways to enhance natural signals that influence hunger and metabolism. This makes it a targeted and physiologically familiar way to support weight loss.

How Does Retatrutide Work?

Retatrutide works by targeting three different receptors:

• GLP-1 receptor: Already targeted by drugs like Wegovy, this pathway reduces appetite, slows digestion and improves blood sugar control. This can lead to reduced calorie intake while also making people feel fuller for longer. 
• GIP receptor: Enhances the body’s insulin response after meals and contributes to satiety (the feeling of fullness). It also contributes to better fat metabolism. This is currently targeted by Mounjaro. 
• Glucagon receptor: Unique to Retatrutide, this pathway stimulates energy expenditure and fat burning.

By combining these three actions, Retatrutide addresses multiple aspects of weight control at once. Patients eat less, feel fuller for longer and burn more energy, which may explain the promising results seen in trials. In addition to these benefits, clinical trials have shown that the medication may improve cardiovascular risk factors and non-alcoholic fatty liver disease. 

Retatrutide Weight Loss Results 

In a 48-week Phase 2 trial published in 2023, Retatrutide produced some dramatic weight loss results. At higher doses, patients lost an average of nearly a quarter of their body weight, exceeding outcomes typically reported with current licensed treatments such as Wegovy (~15%) or Mounjaro (~20%).

Key findings from the study:

• Average weight reduction of 23–24% at 8 mg and 12 mg doses. 
• Some participants lost over 30% of their starting weight. 
• Around 92% of those on 4 mg saw at least 5% weight loss, a meaningful threshold in clinical practice. 
• All patients on the higher doses (8 mg and 12 mg) achieved at least a 5% weight loss, with many exceeding reductions of 10–15%.

Improvements extended beyond weight: participants also experienced improved blood sugar control, lower cholesterol levels, reduced blood pressure, and a smaller waist measurement.

If these findings are confirmed in larger Phase 3 trials, Retatrutide could emerge as a highly effective weight loss injection. That said, it remains in development, and further research is essential to fully establish its long-term safety and efficacy before it is brought to market.

How Long Does Retatrutide Take to Work?

In clinical trials, patients reported feeling less hungry and fuller sooner, typically within the first few weeks, with weight loss often starting in the first month. The most significant reductions developed gradually over several months and continued throughout the 48-week study, showing that Retatrutide is not a short-term fix but a long-term treatment where consistency is crucial.

Is Retatrutide Better than Mounjaro and Wegovy?

The Phase 2 clinical trial shows that Retatrutide will be a serious contender against Wegovy and Mounjaro, with “Triple G’s” unique mechanism of action setting it apart from the rest. In comparison, Wegovy only works on one hormone receptor, while Mounjaro targets two.

The table below outlines some direct comparisons between Retatrutide, Mounjaro, and Wegovy:

Retatrutide Prescription Criteria

When it becomes available in the UK, Retatrutide is likely to follow a similar set of prescribing criteria to other weight loss injections such as Wegovy, Mounjaro, and Nevolat. However, the medication may not be suitable for everyone, as it may interact with other treatments or medical conditions.

The typical prescription criteria for GLP-1 agonists are:

• A body mass index (BMI) of 30 or above
• A BMI of 27 or higher plus at least one weight-related health condition (such as high blood pressure, high cholesterol, or type 2 diabetes)

How to Take Retatrutide 

Retatrutide is given as a once-weekly injection under the skin (subcutaneous). The injection is usually administered into the abdomen, thigh or upper arm. Like other weight loss injections, the medication will be supplied in a pre-filled pen designed for self-administration.

Key points for use:

• Injections should be given on the same day each week. This helps maintain a steady level of medicine in your body. 
• Rotate injection sites to prevent skin irritation/soreness in the same spot. 
• Pens should be stored in the refrigerator, but not frozen. 
• Patients should receive training on the correct injection technique from their clinician before starting.

Most people find the pens quick and straightforward once they’ve tried them. Because the injection is only once a week, it soon becomes part of the routine.

Retatrutide Dosing Schedule

Because Retatrutide hasn’t yet been released in the UK, there’s no official dosing schedule for the medication. However, existing clinical research has suggested that you would begin on a lower strength and gradually titrate up every four weeks. The treatment would also be injected once per week. This is similar to the dosage charts of Mounjaro and Wegovy.

The Phase 2 trial for Retatrutide tested the following strengths:

• 1 mg: This is the lowest dose of retatrutide and was primarily tested to assess tolerability 
• 2 mg: An alternative starting dose, assigned to certain individuals who were to be titrated up to higher levels 
• 4 mg: An intermediate strength of the medication. This could act as a maintenance dose for some users
• 8 mg: Another potential maintenance dose, with a higher percentage of weight loss compared to the 4 mg dosage
• 12 mg: The highest tested strength of Retatrutide. As expected, this is where the largest amount of weight was lost 
   

Retatrutide Side Effects

Like all medicines, Retatrutide can cause side effects, though not everyone will experience them. The most common are digestive issues (stomach-related), particularly when first starting treatment or after increasing the dose. These are very similar to what patients report with other weight loss injections such as Mounjaro and Wegovy.

Reported side effects include:  

• Nausea and/or vomiting 
• Diarrhoea 
• Constipation 
• Stomach discomfort 
• Increase in heart rate (dose-dependent)

Other side effects reported include reduced appetite (also a side effect of the drug), tiredness, and skin sensitivity.

For most people, these symptoms are temporary. Some people find that eating smaller, lighter meals and avoiding very fatty/rich foods in the early weeks helps reduce nausea. Drinking water steadily through the day can also ease digestion.

How Long Do Retatrutide Side Effects Last?

Most digestive side effects tend to appear in the first few weeks of treatment, particularly while the dose is being gradually increased. They are usually mild to moderate in severity and typically ease after the initial weeks. Since side effects are often linked to dose strength, starting on a lower dose helps the body adjust and can reduce their impact. If side effects persist, speak to your clinician.

Can You Buy Retatrutide in the UK? 

No, it’s not possible to buy licensed Retatrutide in the UK. This is because the medication is still undergoing further trials to ensure its safety and suitability for long-term use. While there’s no official guidance on when Retatrutide will become available, it’s expected to happen in 2026.

To gain approval in the UK, the Retatrutide trial data must be reviewed by the Medicines and Healthcare products Regulatory Agency (MHRA). Once this has been done, the medication will become available privately. Further steps will need to be taken for it to be on the NHS.

Retratrudide will be a prescription-only medication, meaning it will not be available for purchase over the counter once it is released. 

Retatrutide Weight Loss FAQs