Retatrutide: what it is, how it works and why you can't buy it in the UK

Retatrutide is the latest weight loss injection to enter clinical trials and is informally known as a triple agonist because it targets 3 hormone receptors to help you lose weight. They are:

1. Glucagon-like-peptide (GLP-1)
2. Glucose-dependent insulinotropic polypeptide (GIP)
3. Glucagon

It is being developed by Eli Lilly the same manufacturer of Mounjaro and Foundayo and is currently in phase 3 clinical trials. The data from this research is not yet available but results from earlier phase 2 trials show the average weight loss on the highest weekly 12mg retatrutride dose was 24.2%.

Retatrutide has not been approved for weight loss in the UK. This means it cannot be legally bought or prescribed in the UK.

Current phase 3 clinical trials results are not yet available. However, the results from phase 2 clinical trials show that weight loss can be achieved in the first few months of starting retatrutide treatment and continue to build over a 48 week period.

There were 4 doses included in the trial, 1, 4, 8, and 12mg and all doses achieved weight loss.

Scroll across to explore the results of this trial. This table presents the average percentage of weight lost for all doses over a 24 and 48 week period:

No, retatrutide is not approved or licensed in the UK because it does not have the relevant approval from the Medicines and Healthcare products Regulatory Agency (MHRA). It is also not available in Europe and has not been approved by the European Medicines Agency (EMA) or the US by their regulatory body the Food and Drug Administration (FDA). Retatrutide is a new weight loss medication and is still at the phase 3 trial stage and can not receive approval for sale until the trials are completed. Trials are estimated to finish in 2026 to 2027.

No, you cannot buy retatrutide in the UK. It is illegal for anyone, including pharmacies, online doctor services, and doctors, to sell retatrutide in the UK. Until retatrutide completes phase 3 trials and is licensed by the MHRA it is not approved for use in the UK.

Although there are reports that retatrutide is being sold illegally online through websites and social media channels, buying it from these outlets is illegal and dangerous. Until retatrutide is licensed there is no way of knowing if you are getting actual retatrutide or if the product was contaminated, of poor quality, or if the dosage is correct.

There are no approved doses for retatrutide at this current time. As retatrutide is still in phase 3 trials, the dosages that are being used are for research purposes only. Once the trials are complete, the dosages will be evaluated to find the best balance between making the medication effective and safe.

In phase 2 clinical trials, the retatrutide doses that were used were:

• starting doses – 1mg, 2mg or 4mg
• maintenance doses – 1mg, 4mg, 8mg or 12mg per week
• maximum dose – 12mg per week

Like other weight loss medications, the doses were increased every 4 weeks. If retatrutide is approved for weight loss in the future, the safe, clinically approved doses will become available and the appropriate dosing schedule will be confirmed.

As retatrutide is still in phase 3 trials there is no actual patient information leaflet (PIL) showing the side effects, but clinical trials have shown that retatrutide side effects are similar to other weight loss medications. This means that gastrointestinal side effects are the most commonly reported side effects of retatrutide.

Phase 2 clinical studies have reported the following side effects on the maximum 12mg dose:

It is not yet known if retatrutide is safe because it is still being researched and is in phase 3 trials. These trials will help to establish if retatrutide is safe or not. If it receives approval from regulatory agencies like the Medicines and Healthcare products Regulatory Agency (MHRA) and the European Medicines Agency (EMA), they will deem it safe to be used in the relevant countries.

Although retatrutide is not currently available in the UK, alternative weight loss medications, such as Mounjaro and Wegovy, are approved and available with a prescription. At Asda Online Doctor, we can provide a wide range of weight loss medications, including injections and pills, to suit your preferences and needs.

Weight loss medications that are approved and available alternatives to retatrutide are:

Other weight loss pills

At Asda Online Doctor we also provide the following fat absorption blockers, which work by stopping the body from absorbing fat, and all contain the same ingredient, orlistat. These medications are available as oral pills that you swallow and can be taken up to 3 times a day with meals that contain fat. They are available in 120mg doses with a valid prescription, or over-the-counter at a lower 60mg dose. These are:

When will retatrutide be available in the UK?

Retatrutide is not available in the UK and there is no set date for its potential release. Phase 3 trials are not due to end until 2026 to 2027. There cannot be any marketing for retatrutide until trials have concluded and regulatory approval is granted from the Medicines and Healthcare products Regulatory Agency (MHRA). If trials are successful, retatrutide may be available in the private market in 2027 to 2028, and potential NHS availability from 2028 onwards, subject to approval from the National Institute for Health and Care Excellence (NICE).

How much will retatrutide cost once it's approved?

There is no estimated retail cost for retatrutide. As the medication is still in phase 3 trials there has not yet been any approval. The cost of retatrutide will be established once approval is obtained from regulatory bodies like the MHRA and is likely to be set by the manufacturer and the provider.

Is "retatrutide peptide" sold online the same as the real drug?

No, retatrutide peptide that is sold online is not the same as retatrutide that is currently in phase 3 clinical trials. Retatrutide peptide sold online will not have undergone important clinical trials and could be dangerous to your health. There will also be other factors that could affect health, such as already reported side effects seen in trials, contamination, counterfeit products, and unsafe dosages.

What's the difference between retatrutide and semaglutide?

The main difference between retatrutide and semaglutide is that semaglutide is a single hormone receptor agonist, while retatrutide is a triple hormone receptor agonist. Semaglutide works by binding to GLP-1 receptors and reduces your appetite. This works by slowing the movement of food through the stomach, slowing the digestion process. It also supports insulin production by helping your pancreas release insulin when your blood sugar rises to help prevent blood sugar spikes. The average weight loss with Wegovy (semaglutide) is 21% of your starting body weight after 72 weeks on the maximum maintenance dose. Semaglutide is safe and approved for weight loss management in the UK.

Retatrutide targets 3 hormone receptors to promote weight loss by slowing the movement of food through the stomach and digestion. Retatrutide also helps release insulin and controls blood sugar levels, and turns stored fat into fatty acids that can be burned to make energy. The average weight loss with the maximum dose of retatrutide in phase 2 clinical trials was 24.2% over 48 weeks. Retatrutide is not yet approved for weight loss treatment and is still in clinical trials.

Does retatrutide burn fat?

Yes, retatrutide has been reported to help your body burn fat by mimicking the effects of a naturally produced hormone called glucagon. Glucagon works by turning stored fat into fatty acids. These fatty acids are then burned up and used as energy, leading to a reduction in body weight by reducing fat storage.