Retatrutide Before and After: What 28.7% Weight Loss Actually Looks Like
Reviewed by Peptide Nerds Editorial · Updated March 2026
Retatrutide Before and After: What 28.7% Weight Loss Actually Looks Like
Key takeaways:
- Retatrutide is still in clinical trials. There are no verified consumer "before and after" results. All data below comes from Phase 2 and Phase 3 trials.
- At 48 weeks in Phase 2, participants on the 12 mg dose lost an average of 24.2% of body weight (PMID: 37385275). Phase 3 data at 68 weeks shows up to 28.7%.
- For a 250 lb person, 28.7% body weight loss equals roughly 72 lbs. For a 200 lb person, roughly 57 lbs.
- Retatrutide is a triple agonist (GLP-1, GIP, and glucagon receptors), which may explain both the greater weight loss and the potential for better lean mass preservation compared to GLP-1-only drugs.
- Most weight loss occurs between months 3 and 9. The first 1-2 months show minimal changes during dose titration.
Important: This is not medical advice. The information below summarizes published clinical trial data and peer-reviewed research for educational purposes only. Always consult a qualified healthcare provider before starting any medication. See our full medical disclaimer.
Why there are no real "before and after" photos for retatrutide
If you searched "retatrutide before and after," you were probably hoping for transformation photos. We need to be upfront: retatrutide is not yet FDA-approved. It is still being evaluated in Phase 3 clinical trials.
Any "before and after" photos you find online claiming to show retatrutide results are unverified. Some social media users claim to have accessed retatrutide outside of clinical trials through research chemical suppliers. These claims cannot be confirmed, and using unapproved compounds outside of a supervised trial carries serious risks.
The only reliable data we have comes from Eli Lilly's Phase 2 trial (PMID: 37385275) published in The New England Journal of Medicine in 2023, and ongoing Phase 3 trials. That data tells a compelling story on its own.
Month-by-month timeline: What the trials show
The Phase 2 trial enrolled 338 adults with obesity and measured weight loss across multiple doses over 48 weeks. Based on the published weight loss curves, here is the approximate trajectory for participants on the 12 mg dose (PMID: 37385275):
| Timeframe | Approximate weight loss | What is happening |
|---|---|---|
| Month 1-2 | 1-3% | Dose titration phase. Starting at low doses, gradually increasing. Minimal visible change. |
| Month 3-4 | 8-12% | Acceleration begins. Reaching higher therapeutic doses. Appetite suppression becomes pronounced. |
| Month 6 | 17-18% | Significant change. Clothing sizes noticeably different. Weight loss trajectory still climbing. |
| Month 9 | 22-24% | Approaching Phase 2 endpoint results. The curve begins to flatten. |
| Month 12 (48 weeks) | ~24.2% (Phase 2) | Phase 2 endpoint at 12 mg. Weight loss is still occurring but at a slower rate. |
| Month 17 (68 weeks) | ~28.7% (Phase 3) | Extended Phase 3 data. Additional months produce meaningful further loss. |
The first two months are the frustrating ones. You are on low doses during titration, and the scale barely moves. This is normal. It mirrors the pattern seen with tirzepatide and semaglutide, where the early weeks are about letting your body adjust before the medication reaches full effect.
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What these numbers look like in real terms
Percentages are abstract. Here is what 28.7% weight loss translates to at different starting weights:
| Starting weight | 28.7% loss | Ending weight |
|---|---|---|
| 200 lbs | ~57 lbs | ~143 lbs |
| 225 lbs | ~65 lbs | ~160 lbs |
| 250 lbs | ~72 lbs | ~178 lbs |
| 275 lbs | ~79 lbs | ~196 lbs |
| 300 lbs | ~86 lbs | ~214 lbs |
These are averages from the highest dose group. Individual results varied widely in the trials. Some participants lost more, some lost less. The 28.7% figure represents the mean, not a guarantee.
For context on the full range of weight loss outcomes, the Phase 2 trial reported that over 90% of participants on the 12 mg dose lost at least 5% of their body weight, and more than half lost 25% or more.
Phase 2 vs Phase 3: How the data compares
The Phase 2 trial (PMID: 37385275) ran for 48 weeks. The Phase 3 program extended to 68 weeks and enrolled a much larger population. Here is how the results compare at the 12 mg dose:
| Trial | Duration | Weight loss (12 mg) | Participants |
|---|---|---|---|
| Phase 2 | 48 weeks | -24.2% | 338 total (across all doses) |
| Phase 3 | 68 weeks | -28.7% | Larger enrollment |
The additional 20 weeks of treatment in Phase 3 produced roughly 4.5 percentage points of further weight loss. This tells us two things. First, the weight loss curve had not fully plateaued at 48 weeks. Second, longer treatment duration matters with retatrutide, just as it does with other incretin-based medications.
How results vary by dose
Not every retatrutide dose produces the same results. The Phase 2 trial tested multiple doses, and the differences are significant (PMID: 37385275):
| Dose | Weight loss at 48 weeks |
|---|---|
| 1 mg | -8.7% |
| 4 mg | -17.9% |
| 8 mg | -22.8% |
| 12 mg | -24.2% |
| Placebo | -2.1% |
The jump from 1 mg to 4 mg is dramatic. The gains from 8 mg to 12 mg are smaller but still meaningful. This dose-response curve is important because the final approved dosing protocol will determine what results most patients can expect.
How retatrutide compares to semaglutide and tirzepatide
This is the question everyone asks. Here is a side-by-side comparison using the best available trial data for each medication at maximum doses:
| Medication | Mechanism | Max dose weight loss | Trial duration |
|---|---|---|---|
| Semaglutide (Wegovy) | GLP-1 only | ~15% | 68 weeks |
| Tirzepatide (Zepbound) | GLP-1 + GIP | ~22.5% | 72 weeks |
| Retatrutide | GLP-1 + GIP + Glucagon | ~28.7% | 68 weeks |
Each new generation of these medications has added a receptor target. Semaglutide activates GLP-1 only. Tirzepatide adds GIP. Retatrutide adds glucagon on top of both. The weight loss numbers have increased with each addition.
For a detailed breakdown of the differences, see our semaglutide vs tirzepatide vs retatrutide comparison.
Body composition: The glucagon advantage
One of the most important emerging findings with retatrutide involves body composition. Losing weight is one thing. Losing primarily fat while preserving muscle is another.
Early data suggests that retatrutide's glucagon receptor activation may offer an advantage here. Glucagon promotes fat oxidation (the breakdown of stored fat for energy) and has effects on energy expenditure that differ from GLP-1 alone.
While comprehensive body composition data from the Phase 3 trials has not yet been published, the mechanism is promising. GLP-1-only drugs like semaglutide have faced criticism for the proportion of lean mass lost during treatment. Tirzepatide showed somewhat better lean mass preservation. Retatrutide's triple mechanism, particularly the glucagon component, may further improve this ratio.
This is still an area of active research. We will update this section as body composition data from the Phase 3 program becomes available.
Side effects that affect the timeline
The retatrutide weight loss timeline is not a smooth line. Side effects during the first 1-3 months can affect both the rate of weight loss and the experience of being on the medication.
The Phase 2 trial reported these rates for GI side effects at the 12 mg dose (PMID: 37385275):
- Nausea: ~24%
- Diarrhea: ~22%
- Vomiting: ~13%
- Constipation: ~11%
These side effects were most common during the dose titration phase (the first 1-3 months) and generally decreased with continued treatment. The pattern mirrors what we see with tirzepatide and semaglutide. Your body needs time to adjust to incretin receptor activation, and the titration schedule exists specifically to minimize these effects.
For some participants, GI side effects during the early months actually contributed to the initial weight loss through reduced food intake. As the side effects stabilize, the medication's appetite-suppressing mechanism takes over as the primary driver.
A warning about unverified sources
We need to address this directly. Retatrutide is not available through any pharmacy or legitimate prescriber. The only legal way to access it right now is through enrollment in a clinical trial.
Some online vendors sell compounds labeled as retatrutide. These are unregulated, unverified, and potentially dangerous. There is no way to confirm what is actually in a vial purchased from a research chemical supplier. The purity, dosing accuracy, and sterility of these products are unknown.
If you are interested in retatrutide, the safest path is to check ClinicalTrials.gov for active enrollment in your area. Eli Lilly's Phase 3 program is ongoing, and sites across the United States and internationally are still recruiting participants.
For the latest on regulatory progress, see our retatrutide FDA approval timeline.
Frequently asked questions
How long does it take to see results on retatrutide?
Based on Phase 2 trial data, most participants began seeing measurable weight loss (3%+ of body weight) by the end of month 2. Visually noticeable changes typically appeared around months 3-4, when cumulative loss reached 8-12%.
Is retatrutide better than tirzepatide?
In terms of average weight loss, retatrutide has produced higher numbers in trials (28.7% vs 22.5%). However, retatrutide is not yet approved, and head-to-head trials have not been conducted. The two drugs also have different side effect profiles. See our full comparison.
When will retatrutide be available?
Eli Lilly's Phase 3 trials are ongoing. If results are positive, an FDA submission could happen in late 2026 or 2027. Approval, if granted, would follow 6-12 months after submission. See our FDA timeline tracker.
Does retatrutide cause muscle loss?
All weight loss interventions result in some lean mass loss. Early mechanistic data suggests that retatrutide's glucagon receptor activation may promote fat oxidation over muscle breakdown, but comprehensive body composition results from Phase 3 have not been published yet.
Can I get retatrutide now?
The only safe, legal access is through clinical trial enrollment. Products sold online as "retatrutide" are unregulated and unverified. We strongly recommend against using research-grade compounds without medical supervision.
Sources
- Jastreboff AM, et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. N Engl J Med. 2023;389(6):514-526. PMID: 37385275
Medical Disclaimer: The content on this page is for informational and educational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. See our full disclaimer.
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