Retatrutide
Retatrutide is an investigational peptide being studied as a potential treatment for obesity, metabolic disorders, and type 2 diabetes. Early clinical studies suggest that this compound may have powerful effects on body weight, metabolism, and blood glucose regulation by targeting several hormonal pathways involved in energy balance.
Retatrutide is currently being developed by Eli Lilly and Company and is undergoing clinical evaluation in humans. As of now, retatrutide has not yet been approved as a medicine in the United States, the European Union, or most other regions.
How tirzepatide works
Retatrutide belongs to a new generation of experimental metabolic therapies sometimes referred to as triple incretin receptor agonists.
The peptide activates three important metabolic hormone pathways:
GLP-1 (glucagon-like peptide-1) receptor
GIP (glucose-dependent insulinotropic polypeptide) receptor
glucagon receptor
By influencing these pathways simultaneously, retatrutide may affect several physiological processes related to metabolism. Its potential mechanisms include:
improving blood glucose regulation by enhancing insulin secretion when glucose levels rise
modulating glucagon signaling, which plays a role in energy balance and metabolism
reducing appetite and increasing satiety, which may support weight loss
increasing energy expenditure, a mechanism currently being studied in metabolic research
Because it targets multiple hormonal systems at once, retatrutide is being investigated as a possible next-generation therapy for obesity and metabolic disease.
Clinical trials and evidence
Retatrutide is currently being evaluated in several clinical studies investigating its safety and effectiveness.
One of the most widely discussed studies is a phase 2 clinical trial published in 2023 that included participants with obesity or overweight. Over the course of the study, participants receiving retatrutide experienced substantial average reductions in body weight compared with placebo.
Additional findings from early research include:
significant weight reduction among participants in higher-dose groups
improvements in markers of metabolic health, including blood glucose control
expected gastrointestinal side effects similar to those seen with other incretin-based therapies
While these results are promising, retatrutide is still undergoing phase 3 clinical trials, which are designed to further evaluate long-term safety and effectiveness in larger patient populations.
Only after the completion of these studies can regulatory agencies determine whether the drug should be approved for medical use.
Possible side effects of Retatrutide:
Because retatrutide is still being studied, the full safety profile is not yet completely established. However, based on clinical trials conducted so far, the most commonly reported side effects are gastrointestinal symptoms, similar to those seen with other incretin-based therapies. Reported side effects in studies include:
nausea
diarrhea
constipation
vomiting
abdominal discomfort
These effects were generally dose-dependent and more common during the early stages of treatment. As with any investigational compound, ongoing research is needed to better understand its long-term safety and potential risks.
References:
– Triple–Hormone‑Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial, Jastreboff et al., 2023 – NEJM, https://www.nejm.org/doi/pdf/10.1056/NEJMoa2301972
– Retatrutide, a GIP, GLP‑1 and glucagon receptor agonist, for people with type 2 diabetes, Rosenstock et al., 2023 – The Lancet, https://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2823%2901053-X/abstract
– Retatrutide for the treatment of obesity, obstructive sleep apnea and knee osteoarthritis, Giblin et al., 2025 – Diabetes, Obesity and Metabolism, https://dom-pubs.onlinelibrary.wiley.com/doi/pdf/10.1111/dom.70209