If you’ve been following the news on weight loss medications like Ozempic, Wegovy, and Mounjaro, you’ve likely heard a new name surfacing in medical circles: Retatrutide.
Often referred to as the "Triple G" or the "Godzilla" of weight loss drugs, Retatrutide is currently the most anticipated medication in the metabolic space. But how does it differ from existing treatments, and when will it be available in Singapore?
In this guide, we break down the science behind Eli Lilly’s newest breakthrough and what it means for the future of chronic weight management.
What is Retatrutide?
Developed by Eli Lilly, Retatrutide is a "triple agonist." To understand why that is a big deal, we have to look at how current medications work:
- Ozempic/Wegovy: Targets one hormone (GLP-1).
- Mounjaro/Zepbound: Targets two hormones (GLP-1 and GIP).
- Retatrutide: Targets three hormones—GLP-1, GIP, and Glucagon.
By mimicking three naturally produced body hormones, Retatrutide addresses weight loss from multiple angles: appetite suppression, blood sugar regulation, and increased energy expenditure.
In clinical trials, Retatrutide is taken as a once-weekly subcutaneous injection.
The "Triple Hormone" Advantage: How It Works
The secret to Retatrutide’s effectiveness lies in the addition of the third hormone: Glucagon.
- GLP-1 (Glucagon-like peptide-1): Slows stomach emptying and tells your brain you are full.
- GIP (Glucose-dependent insulinotropic polypeptide): Improves how the body breaks down sugar and fat.
- Glucagon: This is the game-changer. It increases the amount of energy your body burns while at rest and specifically targets fat in the liver.
By combining these three, Retatrutide doesn't just stop you from feeling hungry; it actively helps your body burn more calories.
The Results: How Much Weight Can You Lose with Retatrutide?
The clinical data for Retatrutide has been record-breaking. In Eli Lilly’s Phase 2 clinical trials (TRIUMPH-1), participants taking the highest dose of Retatrutide lost an average of 24.2% of their body weight over 48 weeks.
To put that in perspective:
- Ozempic/Wegovy typically sees about 15% weight loss.
- Mounjaro typically sees about 20-22% weight loss.
For a patient weighing 100kg, a 24% loss means losing 24kg in less than a year—results previously only seen with bariatric surgery.
Retatrutide vs. Mounjaro vs. Ozempic
Feature | Mounjaro / Zepbound | Retatrutide | |
Hormones Targeted | GLP-1 | GLP-1 + GIP | GLP-1 + GIP + Glucagon |
Avg. Weight Loss | ~15% | ~22% | ~24% |
Administration | Weekly Injection | Weekly Injection | Weekly Injection |
Availability (SG) | Available | Available | Clinical Trials / Pending FDA |
Potential Side Effects
Like all GLP-1 class medications, the most common side effects are gastrointestinal, including:
- Nausea and vomiting
- Diarrhea or constipation
- Heartburn/Acid reflux
Because Retatrutide also targets the Glucagon receptor, researchers are closely monitoring its effect on heart rate. Most side effects occur during the "dose-escalation" phase and usually subside as the body adjusts.
Is It Safe To Take Retatrutide?
Retatrutide is an investigational molecule that is legally available only to participants in Lilly’s clinical trials, and Lilly is currently evaluating its safety and efficacy in these clinical studies. It has not been reviewed or approved by any regulatory agency, and no one should consider taking anything claiming to be retatrutide outside of a Lilly-sponsored clinical trial. Lilly continues to warn the public about the potential dangers of fake medicines.
When Will Retatrutide Be Available To The Public?
Retatrutide is not yet available for public use.
Lilly is currently studying Retatrutide in Phase 3 clinical trials for obesity, type 2 diabetes, knee osteoarthritis pain, moderate-to-severe obstructive sleep apnea, chronic low back pain, cardiovascular and renal outcomes, and metabolic dysfunction-associated steatotic liver disease.
Retatrutide is also not currently approved by the FDA.
When Will Retatrutide Be Available in Singapore?
As of early 2026, Retatrutide is in the final stages of Phase 3 clinical trials globally.
In Singapore, medications must undergo rigorous review by the Health Sciences Authority (HSA) before they can be prescribed. While it is not yet available for general prescription, the success of the trials suggests that it will eventually become a core part of the obesity treatment toolkit in Singapore.
Is Retatrutide Right for You?
While Retatrutide promises incredible results, it is not a "magic pill." Like Mounjaro and Wegovy, it is designed to be used alongside a calorie-controlled diet and regular physical activity.
At Siena Health, we believe weight management is a journey best taken with medical guidance. Whether you are interested in currently available treatments like Mounjaro or want to stay updated on the arrival of Retatrutide, our doctors are here to help you navigate your options safely.
Ready To Start Your Transformation?
If you’re ready to explore safe, clinically supervised weight-loss treatments tailored to your health needs, book a consultation with Siena Health today — we can help guide you to the right solution.