
Retatrutide
Overview
Retatrutide is a next‑generation weight loss medication being studied for people living with obesity. This treatment targets three key hormone pathways. These pathways control appetite and digestion. The goal is to achieve better and longer-lasting weight management results.
Currently, this treatment remains in clinical development and is not yet available to buy.
Retatrutide Summary
| Retatrutide Dosing | Weekly subcutaneous injection (anticipated via a pre‑filled Retatrutide pen if approved). The final dosing schedule will be confirmed after licensing. |
| How it Works | Tri‑agonist: activates GLP‑1, GIP and glucagon receptors to reduce hunger and slow digestion. |
| Effectiveness | In Phase 2, the highest dose produced up to 24.2% average weight loss at 48 weeks (17.5% at 24 weeks). Lower doses still showed meaningful reductions; placebo averaged ~2%. |
| Retatrutide Price & Cost | Not yet announced (TBC). |
| Side Effects | Most commonly gastrointestinal: nausea, vomiting, diarrhoea and constipation—often most noticeable when starting or increasing the dose. A full list of side effects and contraindications will be available after licensing. |
| Retatrutide UK Availability | Not yet licensed; still in clinical trials. Availability dates are not confirmed. |
What is Retatrutide?
Retatrutide is a weekly injection that acts on three hormone receptors to support weight loss. This treatment works by helping you feel fuller for longer and slowing digestion. Combined with diet changes and increased exercise, this can help you lose weight.
Retatrutide is currently in Phase Three clinical trials. Normally, this is the last set of clinical trials before a medication can be licensed.
How Does Retatrutide Work?
Retatrutide is a tri‑agonist. It works on three different receptors in your body;
- Glucagon-like peptide-1 (GLP‑1) regulates blood sugar and appetite
- Glucose-dependent insulinotropic polypeptide (GIP) regulates insulin
- Glucagon controls blood sugar levels
Together, these multiple pathways are all involved in appetite, satiety and digestive speed.
This means you should feel fuller for longer, even when you eat less food. In some cases, it can help reduce overall hunger. Combined with diet and exercise, this can help many people lose weight.
Retatrutide Clinical Trial Results
Retatrutide is still in the experimental phase. In a Phase 2 trial, people on the highest dose lost 24.2% of body weight at 48 weeks, and 17.5% at 24 weeks. Weight loss was dose‑dependent (for example, ~8% at 1 mg), while the placebo group lost around 2%. Even at the lowest doses, this treatment showed statistically significant weight loss potential.
Individual results vary and depend on dose, duration and lifestyle changes alongside treatment.
Phase 3 clinical trials are still underway, coming to a close in May 2026. If they are successful, the next step will be applying for a licence for the medication.
Side Effects of Retatrutide
A complete safety profile will be confirmed after larger, longer studies. The most commonly reported side effects from the clinical trials are;
- Nausea
- Diarrhoea
- Vomiting
- Constipation
These are similar to other GLP-1 receptor agonist weight loss drugs. These tend to be most noticeable at the start or after dose increases. Usually, they will improve as your body adjusts. Speak to a clinician if symptoms are severe or persistent.
How to Take Retatrutide
Retatrutide is expected to be given once weekly as a subcutaneous injection into the abdomen, thigh or upper arm. Ideally, this should be done at the same time and day each week. Rotating injection sites helps to minimise local irritation. A pre‑filled pen is anticipated, similar to other modern incretin pens.
Retatrutide Price & Cost
No official UK pricing is available yet. Retatrutide’s cost will depend on licensing, supply and guidance in the UK. We will update this section when confirmed information is released.
Storage Guidance
Formal storage instructions are not yet published. Based on similar medicines, pens are often kept refrigerated at 2°C–8°C and protected from light (do not freeze). Always follow the Patient Information Leaflet that accompanies the medicine once licensed.
Contraindications and Interactions
Retatrutide is still in trial phases. A full list of who should avoid it and how it interacts with other medicines hasn't been finalised. Your prescriber will assess your medical history and other treatments to decide whether this treatment is suitable for you.
FAQs
What is Retatrutide?
Retatrutide is an investigational weekly injection targeting three hormone receptors (GLP‑1, GIP and glucagon) to support weight loss. It is not yet licensed in the UK.
How Does Retatrutide Work?
Retatrutide is a tri‑agonist that reduces hunger and slows digestion by activating three different receptors together.
What is the Recommended Retatrutide Dose?
Final dosing will be confirmed after approval. Current clinical studies use a weekly schedule, with dose increases over time to support tolerability.
What are Retatrutide side effects?
Commonly reported effects in studies include nausea, diarrhoea, vomiting and constipation. The full list will be available after licensing.
How do I use the Retatrutide pen?
Details on how the pen itself works are not yet available.
How do I store it?
Official guidance is pending. Similar pens are usually stored at 2°C–8°C in the original carton. Always follow the package leaflet when available.
Are there alternatives for weight loss?
Licensed options include;
- GLP‑1 treatments such as semaglutide (Wegovy)
- Dual‑agonists such as tirzepatide (Mounjaro)
- Non‑injectable options such as orlistat.
Your clinician can help you choose what’s right for you.
Can I buy Retatrutide online?
No. Retatrutide is still in clinical development and not available to purchase. Avoid unregulated sources and speak to a healthcare professional for safe, licensed alternatives.
We’ll keep this page updated as robust data emerges from Retatrutide clinical trials and UK regulators release guidance. If you have questions about current weight‑loss treatments, our clinical team is here to help.
FAQ
General Information
What are weight loss injections like Mounjaro, Wegovy, and Ozempic?
Who can use weight loss injections?
Can I use Wegovy or Mounjaro without diabetes?
Is a GLP-1 injection like insulin?
Is there a pill form of GLP-1 treatments?
Effectiveness & Results
How effective are GLP-1 injections for weight loss?
How quickly do weight loss injections work?
Why am I not losing weight with my Weight Loss Pen?
What if my GLP-1 injection isn’t effective enough?
Do weight loss pens have benefits besides weight loss?
Will I regain weight after stopping injections?
Which is the most effective weight loss injection for weight loss?
Administration & Usage
How are GLP-1 medications administered?
Do weight loss injections hurt?
Where should I inject weight loss injections?
What if I miss a dose?
What if I take an overdose?
Alcohol and GLP-1 treatments?
Special diet or exercise needed with weight loss injections?
How do I store weight loss pens?
Can I travel with injections?
Can I switch Weight Loss Pen?
Safety & Side Effects
Are GLP-1 treatments safe?
What are common side effects of GLP-1 treatments?
Do GLP-1 weight loss injections cause low blood sugar?
How do I manage nausea when taking weight loss injections?
Will nausea fade over time?
Can I use GLP-1 treatments with other diabetes medications?
Product Comparison & Availability
What are the differences between injections?
Wegovy: single-hormone, high-dose treatment for obesity (around 15% average weight loss).
Ozempic: primarily for diabetes at lower doses, offering moderate weight loss.
Are they available on the NHS?
Ozempic is prescribed for diabetes only.
Mounjaro has been approved recently for both obesity and diabetes, with access initially limited to specialist clinics.
What do they cost privately?
Can I buy online without a prescription?
What alternatives can I consider and how do they compare?
Compare
Treatment Comparison
| Saxenda | Xenical | Orlistat | Mysimba | |
| Ingredient | Liraglutide | Orlistat 120mg | Orlistat 120mg | Naltrexone/Bupropion |
| Mechanism | Regulates appetite | Reduces fat absorption | Reduces fat absorption | Regulates appetite |
| Dose | Injected once daily | One three times daily with meals | One three times daily with meals | Gradually increased to 4 tablets daily |
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