Retatrutide: 7 Key Facts About the Triple-Hormone Weight-Loss Drug
What Is Retatrutide?
Retatrutide is an investigational weight-loss medicine that has attracted huge attention on social media in Egypt and around the world. It is developed only by Eli Lilly under the code LY3437943 and is given in studies as a once-weekly injection. This guide explains 7 key facts: how it works, what the trials found, its side effects, how it differs from semaglutide and tirzepatide, and why you cannot get it legally yet.
Important: No Style Like pharmacy does not sell this medicine, and we kindly advise you not to buy or inject any unapproved pen or vial offered online. If you need help with weight, please talk to your doctor about approved options.
1. A Triple Agonist: GIP, GLP-1 and Glucagon
Most weight-loss injections in use today act on one or two gut hormones. Semaglutide acts on the GLP-1 receptor, and tirzepatide acts on both GIP and GLP-1. Retatrutide adds a third target, the glucagon receptor, which is why it is often called a “triple G” agonist.
- GLP-1: reduces appetite, slows stomach emptying and helps control blood sugar after meals.
- GIP: works alongside GLP-1 on appetite and insulin release and may improve how the body handles fat.
- Glucagon: is thought to raise energy use and help the liver burn fat, adding to the effect on weight.
The idea is that combining three signals may produce more weight loss than one or two. To understand the single-hormone approach first, read our Ozempic guide.
2. Phase 2 Results in the NEJM
The first large human study was a phase 2 trial published in the New England Journal of Medicine in June 2023 (Jastreboff and colleagues). Adults with obesity lost up to about 24% of their body weight on average after 48 weeks on the highest dose, 12 mg. This was one of the largest average losses ever reported for a medicine at that time, and it pushed retatrutide into phase 3 testing.
3. Retatrutide Phase 3: The TRIUMPH-1 Trial
TRIUMPH-1 is the main phase 3 trial, and its topline results were announced on 21 May 2026. It included about 2,339 adults with obesity, or with overweight plus at least one weight-related condition, followed for 80 weeks. Participants received retatrutide 4 mg, 9 mg or 12 mg once weekly, or placebo.
| Group | Average weight loss at 80 weeks | Stopped due to side effects |
|---|---|---|
| 4 mg | 19.0% | 4.1% |
| 9 mg | 25.9% | 6.9% |
| 12 mg | 28.3% | 11.3% |
| Placebo | About 2% | 4.9% |
The weight-loss figures are for people who stayed on treatment. On the 12 mg dose, 45.3% of participants lost 30% or more of their body weight. A 104-week extension in people with a BMI of 35 or more on 12 mg reported about 30.3% average loss. A separate trial, TRIUMPH-2, in people with type 2 diabetes reported up to about 20.8% weight loss and met its main goal.
In all of these studies, doses were started low and raised step by step under close medical supervision. These numbers come from controlled research settings and cannot be copied at home.
4. Side Effects Seen So Far
The most common side effects were digestive, similar to other medicines in this class. In retatrutide trials these included:
- Nausea, diarrhea, constipation and vomiting, mostly mild to moderate and mainly during dose increases.
- Dysesthesia, meaning abnormal or uncomfortable skin sensations, in a subset of participants, generally mild.
- Increased heart rate, which has been seen with this drug class.
Notice in the table that more people stopped treatment because of side effects on the highest dose (11.3%) than on placebo (4.9%). Full safety data are still being reviewed by regulators, and long-term safety is not yet established. For the side effects of an approved medicine in the same family, see Ozempic side effects.
5. How Retatrutide Differs From Semaglutide and Tirzepatide
| Item | Semaglutide | Tirzepatide | Retatrutide |
|---|---|---|---|
| Targets | GLP-1 | GIP + GLP-1 | GIP + GLP-1 + glucagon |
| Brand examples | Ozempic, Wegovy | Mounjaro, Zepbound | None (investigational) |
| Approval status | Approved | Approved | Not approved anywhere |
| Long-term safety | Years of real-world use | Growing real-world use | Not yet established |
The key practical difference is simple: semaglutide and tirzepatide can be prescribed and monitored by a doctor today, while retatrutide exists legally only inside clinical trials. Bigger trial numbers do not make an untested product safer for an individual patient.
6. Why Retatrutide Is Not Available Yet
As of October 2026, retatrutide is not approved by the US FDA, the European EMA, the UK MHRA or the Egyptian Drug Authority. Lilly has announced plans to submit it for approval, with reported filing plans pointing to around late 2026 or early 2027, but no approval date is set and approval is not guaranteed. We explain the process in detail in is retatrutide approved.
7. Beware of Pens Sold Online
Because Lilly does not sell retatrutide, any pen, vial or “research peptide” offered on TikTok, WhatsApp or websites is not a genuine Lilly product. These items may contain the wrong drug, the wrong dose or nothing at all, and may be contaminated. Learn how to spot them in fake retatrutide pens.
Frequently Asked Questions
Can I buy retatrutide from a pharmacy in Egypt?
No. It is not approved in Egypt, so no licensed pharmacy can sell it. No Style Like pharmacy does not sell it either.
Is retatrutide stronger than Ozempic?
Average trial results were larger, but the drug is not approved and its long-term safety is unknown. A doctor can tell you which approved option suits you.
Does it work for people with diabetes?
TRIUMPH-2 studied people with type 2 diabetes, but people with diabetes face extra risks, such as low blood sugar when combined with other medicines, so this must only happen in a trial.
What are the approved alternatives?
Semaglutide (Ozempic, Wegovy), tirzepatide (Mounjaro, Zepbound) and liraglutide (Saxenda), prescribed by a doctor together with diet and activity. Read more in Ozempic uses.
Conclusion
Retatrutide is a promising triple-hormone injection that produced large average weight loss in phase 2 and in TRIUMPH-1, with mainly digestive side effects. But it is still investigational, it is not approved anywhere, and its long-term safety is unknown. No Style Like pharmacy does not sell it, and we kindly advise you not to buy or inject unapproved pens. Talk to your doctor about approved, supervised options instead.
This article was reviewed by the No Style Like pharmacy content team. It is for general awareness only and does not replace advice from your doctor or pharmacist.
Do not use any weight-loss injection without a doctor’s prescription and follow-up. For more information see the phase 2 study in the New England Journal of Medicine.