Reta 2023 trial results explained: retatrutide's Phase 2 data showed up to 24% weight loss in 48 weeks, plus safety signals, comparisons, and FDA status.
Reta 2023 refers to the year retatrutide — commonly shortened to "reta" — delivered its first major clinical results. In 2023, a Phase 2 trial reported that this investigational triple-hormone agonist produced average weight loss of up to about 24% over 48 weeks, the largest reduction reported for any obesity drug candidate at that point. Retatrutide remains experimental and is not FDA-approved for human use.
What Is Reta (Retatrutide)?
Retatrutide is an investigational injectable drug developed by Eli Lilly, known during early research by the code LY3437943. It is a triple agonist, meaning it activates three hormone receptors at once: GLP-1, GIP, and glucagon.
Most familiar weight-loss medications target fewer pathways. Semaglutide (Wegovy) activates GLP-1 only. Tirzepatide (Zepbound) activates GLP-1 and GIP. The added glucagon activity is the main reason researchers expected reta to produce larger effects, since glucagon signaling raises energy expenditure.
Retatrutide is given as a once-weekly subcutaneous injection and was studied in adults with obesity, or with overweight plus at least one weight-related health condition.
What Actually Happened With Reta in 2023
The defining reta 2023 event was the release of Phase 2 trial data. Results were presented at the American Diabetes Association annual meeting in June 2023 and published in the New England Journal of Medicine.
- Design: randomized, double-blind, placebo-controlled, with 48 weeks of treatment
- Participants: 338 adults with obesity, or overweight with a related condition
- Doses studied: 1 mg, 4 mg, 8 mg, and 12 mg, plus placebo
- Primary focus: percent change in body weight at 24 and 48 weeks
Investigators also launched the Phase 3 TRIUMPH program in 2023, which is still the basis for any future approval. Retatrutide has not completed Phase 3 testing.
Reta 2023 Weight Loss Results
At 48 weeks, every active dose produced greater weight loss than placebo, and participants were still losing weight when the treatment period ended. The numbers below are approximate means from the Phase 2 trial.
| Dose | Average weight change at 48 weeks | Notes |
|---|---|---|
| Placebo | About −2% | Diet and lifestyle counseling only |
| 1 mg | About −9% | Lowest active dose |
| 4 mg | About −17% | Mid-range dose |
| 8 mg | About −23% | Weight loss still ongoing at week 48 |
| 12 mg | About −24% | Largest effect reported in 2023 |
Because participants had not plateaued at 48 weeks, longer trials could show larger totals. That possibility stays unproven until Phase 3 data are available.
How Reta Compares With Tirzepatide and Semaglutide
Any tirzepatide vs reta comparison has to start with a caveat: the two drugs were never tested head-to-head, and their trials used different durations and populations.
| Drug | Receptors targeted | US approval status | Reported weight loss |
|---|---|---|---|
| Semaglutide (Wegovy) | GLP-1 | Approved | About 15% at 68 weeks |
| Tirzepatide (Zepbound) | GLP-1 + GIP | Approved | About 21% at 72 weeks |
| Retatrutide | GLP-1 + GIP + glucagon | Not approved | About 24% at 48 weeks (Phase 2) |
Retatrutide's numbers come from a smaller, shorter mid-stage trial, while the approved drugs have finished large Phase 3 programs. Retatrutide also is not FDA-approved, so no pharmacy can legally dispense it for human use.
Side Effects and Safety Signals Reported in 2023
Gastrointestinal effects were the most common complaint, which is consistent with other GLP-1-based drugs.
- Nausea, diarrhea, vomiting, and constipation
- Most events were mild to moderate and clustered during dose escalation
- Some participants stopped treatment because of GI symptoms
- Small increases in resting heart rate were observed
- Uncommon reports of tingling or altered skin sensation were noted and required follow-up
The 2023 data covered only 48 weeks of treatment in a few hundred people. That is far too short and too small to define the long-term safety profile of retatrutide.
Availability, Blends, and What to Know Before Buying
Retatrutide cannot legally be sold as a prescription drug or a dietary supplement in the United States. Products marketed as "reta" are typically sold as research chemicals labeled "not for human consumption," which means purity, sterility, and actual content are not verified by any regulator.
Online discussion often mixes reta with cagrilintide, another investigational peptide. Talk about cagri reta blend benefits is based on user anecdotes rather than controlled trials, and no study has established that combining the two is safe or effective. A cagri reta pen sold by a gray-market vendor has no manufacturing oversight, and any cagri reta blend dosage circulating online is guesswork rather than a tested protocol. Threads such as cagri reta reddit posts can help people spot patterns in reported side effects, but they are not medical evidence.
Anyone considering an investigational weight-loss drug should talk with a licensed healthcare professional first, and should be skeptical of sellers promising prescription-level results without a prescription.
Frequently Asked Questions
What were the reta 2023 trial results?
The 2023 Phase 2 trial of retatrutide enrolled 338 adults with obesity and ran for 48 weeks. Average weight loss reached roughly 24% at the 12 mg dose and about 23% at 8 mg, compared with about 2% on placebo. Participants were still losing weight when the study ended, and the data were published in the New England Journal of Medicine.
Is retatrutide FDA approved?
No. Retatrutide is not FDA-approved for any use in the United States and remains an investigational drug. It is being evaluated in the Phase 3 TRIUMPH program, and outside of a clinical trial there is no legal prescription supply.
Can you legally buy retatrutide online?
No legal retail or prescription supply of retatrutide exists in the United States. Products sold online are usually labeled as research chemicals not for human consumption, so their identity, purity, and sterility are unverified. Talk to a licensed healthcare professional about approved options instead.
This page provides educational research information and does not replace medical advice, diagnosis, or treatment.