What Is
Retatrutide?
Retatrutide is a once-weekly injectable peptide being studied for obesity and metabolic health. It is known as a triple agonist because it targets GLP-1, GIP, and glucagon receptors at the same time.
The Simple Explanation
What Retatrutide is, where it comes from, and why it matters
A GLP-1/GIP/Glucagon Triple Agonist
Retatrutide (also known by its development code LY3437943) is a once-weekly injectable peptide being studied for obesity and metabolic health.
Unlike older GLP-1 medications that target a single hormone pathway, Retatrutide activates GLP-1, GIP, and glucagon receptors simultaneously.
This triple-action mechanism may influence appetite, glucose control, metabolism, and fat mobilisation at the same time.
Developed by Eli Lilly
Eli Lilly developed Retatrutide as a next-generation evolution beyond tirzepatide.
The addition of glucagon receptor activity is one of the major differences researchers believe may contribute to stronger metabolic effects and greater weight reduction.
Phase 2 trial results reported substantial body-weight reductions over 48 weeks, leading to major interest in ongoing Phase 3 research.
Retatrutide Quick Facts
A simple overview before going deeper into the science.
The Three Hormones Explained
Understanding each target helps explain why Retatrutide works better than
anything before it
GLP-1
(Glucagon-Like Peptide-1)GLP-1 helps reduce hunger, increase fullness, slow gastric emptying, and support blood sugar control.
GIP
(Glucose-Dependent Insulinotropic Polypeptide)GIP supports insulin response, glucose handling, and may improve how the body manages energy after eating.
Glucagon
(The Fat-Burning Hormone)Glucagon may increase energy expenditure and help mobilise stored fat, including fat stored around the liver.
Why Triple Is Greater Than the Sum of Three
GLP-1 reduces calories in. GIP improves how those calories are processed. Glucagon may increase calories burned at rest.
The Evolution of Weight Loss Medicine
Retatrutide is the latest — and most powerful — step in a rapidly advancing drug class.
Liraglutide (Saxenda)
GLP-1 Single Agonist — Novo NordiskThe first GLP-1 receptor agonist approved for obesity. Delivered daily, it produced modest weight loss.
~5–8% weight lossSemaglutide (Wegovy / Ozempic)
GLP-1 Single Agonist — Novo NordiskA more potent weekly GLP-1 agonist that transformed obesity treatment worldwide.
10–15% weight lossTirzepatide (Mounjaro / Zepbound)
GLP-1 + GIP Dual Agonist — Eli LillyAdding GIP receptor activation created stronger weight-loss results than GLP-1 alone.
20–22% weight lossRetatrutide (LY3437943)
GLP-1 + GIP + Glucagon Triple Agonist — Eli LillyThe addition of glucagon receptor activity creates a third pathway for fat mobilisation and energy expenditure.
Up to 24% weight lossWho Is Retatrutide For?
Retatrutide is a prescription treatment — understanding candidacy is the first step
Good Candidates
- Adults with a BMI of 30 or above (obesity)
- Adults with BMI 27+ and at least one weight-related condition
- People who have not achieved sufficient weight loss through diet and exercise alone
- Those who have previously used Semaglutide or Tirzepatide with unsatisfactory results
- Adults aged 18–75 without contraindicated medical conditions
Not Currently Suitable
- Personal or family history of medullary thyroid carcinoma (MTC)
- Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
- History of pancreatitis
- Pregnancy or planning to become pregnant
- Severe gastrointestinal disease (gastroparesis)
- Type 1 diabetes
Requires Evaluation
- Existing diabetes medications (dose adjustments likely needed)
- Kidney or liver disease (needs assessment)
- Active cardiovascular conditions
- History of eating disorders
- Currently breastfeeding
A free consultation with our medical team will determine your candidacy with no obligation.
The Clinical Evidence
What the trial data actually shows.
Mean body weight loss
At the highest dose over 48 weeks in Phase 2 trials.
Patients lost ≥15% body weight
The majority achieved clinically significant weight reduction.
Reduction in liver fat
Large reductions across dose groups in NAFLD-related liver fat measurements.
Waist circumference reduction
Suggesting preferential visceral fat reduction.
📋 Data sourced from the Phase 2 Retatrutide trial (NEJM 2023) and ongoing Phase 3 TRIUMPH trials. Results vary between individuals.
Common Questions About Retatrutide
Clear answers about what Retatrutide is, how it compares to other treatments, approval status, and what to know before starting.
No. Ozempic contains semaglutide, which mainly targets the GLP-1 receptor. Retatrutide is different because it targets three pathways: GLP-1, GIP, and glucagon. This triple-agonist activity is why Retatrutide is being studied for stronger effects on appetite, metabolism, and body weight.
No. Mounjaro contains tirzepatide, which is a dual GIP and GLP-1 receptor agonist. Retatrutide goes one step further by also activating the glucagon receptor, making it a triple agonist with a broader metabolic mechanism.
Retatrutide is still under clinical investigation and is not currently FDA approved for obesity treatment. It is being studied in advanced clinical trials, but patients should understand that it remains a research-stage medication and should only be considered with proper medical guidance.
Some people notice appetite reduction earlier, especially during the first few weeks. However, major body-weight changes usually build gradually over several months as the dose is increased and the body adapts. The best results usually come from consistent dosing, nutrition control, and long-term follow-up.
No. The 24% figure comes from clinical trial averages and should not be treated as a guaranteed personal result. Individual outcomes vary depending on starting weight, dose, treatment duration, diet, activity level, metabolism, and medical background.
Retatrutide is usually considered for adults seeking significant weight loss support, especially those who have struggled with appetite control or have not achieved enough progress with lifestyle changes alone. Suitability depends on BMI, medical history, current medications, and risk factors.
Yes. Like other incretin-based treatments, Retatrutide may cause nausea, reduced appetite, constipation, diarrhea, reflux, bloating, or injection-site irritation. Side effects are often strongest during dose increases, which is why gradual escalation is important.
Yes. A medical review is important before starting. It helps check suitability, contraindications, medication interactions, correct starting dose, realistic expectations, and safety monitoring during treatment.
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