What is Retatrutide?
Eli Lilly has recently developed a new drug for weight reduction named Retatrutide. It is a tri-agonist GLP-1 medication for the management of obesity. Retatrutide is targeted towards those who are overweight or obese. A person considered to be overweight, has a body mass index (BMI) of 25 to 29.9, while a person who is obese has a BMI of 30+.
Retaturtide works in a similar fashion to other weight loss drugs such as Saxenda, Mounjaro and Wegovy. But, it is also a GIP and glucagon receptor agonist. The medication is administered via injection only once a week. Retaturtide is currently in Phase III of development for obesity and type 2 diabetes.
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How Does Retatrutide Work, and What is it Used For?
Retatrutide is developed with the purpose of being a medication offered to treat obesity and type 2 diabetes. As a tri-agonist medication for weight loss to help manage obesity, Retatrutide targets three different hormones in the body that relate to appetite and how hungry you are.
These hormones are called gastric inhibitory peptides (GIP), glucagon-like peptide-1 (GLP-1) and glucagon. GIP is produced and secreted by the gut, after eating food. When released, GIP triggers the beta cells in the pancreas to produce insulin, which leads to an increase in insulin levels in the blood. The GLP-1 hormone works in a similar way to GIP and will also result in an increase in blood insulin levels. The increased insulin levels will lower blood sugar levels which can also help lose weight.
Glucagon is another hormone, which is produced by the alpha cells in the pancreas. Glucagon has two roles affecting blood glucose. It triggers the liver to produce glucose by breaking down sugar that is stored in the body. Sugar is usually stored in fat, so when producing sugar, this can lead to weight loss. So, therefore glucagon regulates glucose levels in the blood.
These hormones, above, particularly GLP-1 and glucagon, also have another effect on hunger and appetite. This effect is delayed gastric emptying (GE). Delayed gastric emptying slows the release and movement of food from your stomach to your intestines.
This, in turn, will have an effect on glucose levels after eating a meal. Delayed GE can also reduce food intake due to a suppressed appetite as you may be feeling less hungry. This can result in weight loss. However, GIP does not seem to have an effect on gastric emptying.
What is the Retatrutide Dose for Weight Loss?
Currently, Retatrutide is not approved in the UK for treating obesity and type 2 diabetes. As mentioned above, it is currently in Phase III of testing. However, results from the Phase II clinical trial, conducted by Eli Lilly, showed that Retatrutide could be a viable option for causing weight loss.
A group of 338 adults were split into two groups; one given doses of Retatrutide ranging from 1 mg to 12 mg and the other group given a placebo. The first checkpoint for weight loss was after 24 weeks taking Retatrutide.
As much as 12.9% and 17.3% weight loss was experienced in overweight adults who were taking 4 mg and 8 mg of Retaturtide respectively. After 48 weeks, those individuals who took the highest dose of Retaturtide at 12 mg once a week, experienced 24% change in weight, while the placebo group only experienced weight loss of 2%. Majority of those who were taking Retatrutide lost more than 5% of their original body weight after 48 weeks.
It appears from the trial results that use of Retatrutide results in dose-dependent weight loss. Therefore, the higher the dose of Retatrutide, the greater the amount of weight that will be lost. When approved, after further research, Retatrutide’s weight loss potential is clearly worth looking into.
What are the Doses for Retatrutide and How to Take It?
Since Retatrutide is still in Phase III of its development, the exact doses of the medication has not yet been decided. Of course, the main priority is to develop a dosing schedule that minimises the effects of side effects felt because of the medication. In the Phase II trial, researchers administered Retatrutide via an injectable pen once a week. The doses, given over the 48 week period, used in the study are shown below:
| Doses | Initial Dose |
|---|---|
| 1 mg | 1 mg |
| 4 mg | 2 mg or 4 mg |
| 8 mg | 2 mg or 4 mg |
| 12 mg | 2 mg |
Retatrutide was also administered subcutaneously which means it is delivered under the skin. And so, the delivery of Retatrutide is similar to the other weight loss drugs such as Mounjaro and Wegovy. It is important to realise that the doses for Retatrutide are not fixed and will need further studies to confirm the doses and dosing schedule.
What are the Side Effects of Retatrutide?
Retatrutide shares similar side effects to other GLP-1 medications. These side effects tend to affect the digestive system. The Phase II trials found the following adverse effects experienced to be the most common after taking Retatrutide:
- Feeling sick (nausea)
- Diarrhoea
- Vomiting
- Constipation
These side effects were described as dose-related and were experienced when increasing the dose of Retatrutide. They were mild to moderate in severity. Also, at lower doses, like 4 mg or 2 mg, the side effects were experienced less.
There were other adverse effects experienced by those in the trial. There was an increase in heart rate experienced until 24 weeks of taking Retatrutide, after which it decreased. 7% of patients felt skin tingling. However, further investigations are required into other side effects of Retatrutide.
References
Triple–Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial – accessed 01/09/2023
Tamsin started with Simple Online Pharmacy in 2022. She is currently studying towards a degree in Medicine. As a medical writer, she generates clinically-informed site content.
