Retatrutide Before and After: What to Expect from Trial Data

Overview

There are no verified retatrutide before-and-after photos because the drug is not yet commercially available — it remains an investigational compound accessible only through clinical trials. However, the Phase 2 trial published in the New England Journal of Medicine provides detailed quantitative data on body weight changes, body composition shifts, and metabolic improvements observed over 48 weeks. This article translates that clinical data into a realistic picture of what retatrutide transformation looks like by the numbers, without relying on unverifiable social media claims.

What Clinical Trial Data Shows

No commercial before-and-after photos exist for retatrutide because the drug has not received FDA approval and is not available outside of clinical trials. What we can describe are the quantitative body composition changes observed in the Phase 2 trial conducted by Jastreboff et al. and published in the New England Journal of Medicine in 2023. In that trial, 338 adults with obesity or overweight received retatrutide at doses ranging from 1 mg to 12 mg weekly over 48 weeks. The highest-dose group (12 mg) achieved a mean weight loss of 24.2% of body weight — the largest reduction ever reported in a Phase 2 anti-obesity drug trial. Participants in the 8 mg group lost 22.8%, and the 4 mg group lost 17.5%. These data points, rather than anecdotal photos, provide the most reliable picture of what participants experienced during the trial.

Expected Weight Loss Timeline

Retatrutide dosing follows a gradual titration schedule, and weight loss tracks accordingly. The drug starts at 0.5 mg per week and escalates over several months toward the maintenance dose. Based on the Phase 2 trial data, the trajectory of weight loss can be broken into approximate phases. During the early titration period, weight loss is modest as the body adjusts to the medication. As doses increase through the mid-study period, weight loss accelerates noticeably. The steepest rate of weight reduction occurs as participants approach and reach their maintenance dose. Notably, the weight loss curves in the 12 mg group had not plateaued by the end of the 48-week study period, suggesting that additional weight loss may have continued with longer treatment. The 12 mg group averaged approximately 0.5% body weight loss per week during the peak loss period.

• Weeks 1–4: Titration begins at 0.5 mg; modest initial weight change
• Weeks 4–16: Dose escalation; weight loss accelerates noticeably
• Weeks 16–24: Approaching maintenance dose; steepest weight reduction
• Weeks 24–48: Continued progressive loss; curves had not plateaued by study end

Body Composition Changes

The weight lost during retatrutide treatment included both fat mass and some lean mass, which is consistent with all significant weight loss interventions regardless of the method used. However, the glucagon receptor component of retatrutide’s triple-agonist mechanism may promote preferential fat oxidation — increased hepatic energy expenditure and lipid metabolism driven by glucagon receptor activation could theoretically shift the ratio of fat-to-lean mass loss compared to GLP-1-only agonists. In a sub-study of participants with metabolic dysfunction-associated steatotic liver disease (MASLD), retatrutide produced up to an 81% reduction in liver fat content as measured by MRI-PDFF, a striking finding that underscores the drug’s metabolic effects beyond simple weight reduction. Waist circumference also decreased significantly across all dose groups in the Phase 2 trial, reflecting meaningful reduction in visceral adiposity. These composition-level changes matter because visceral fat and liver fat are more closely linked to cardiometabolic risk than total body weight alone.

What 24% Weight Loss Looks Like in Practice

Clinical trial percentages can be difficult to visualize without concrete examples. A mean weight loss of 24% translates to substantial physical changes at any starting weight. For a person starting at 250 pounds, 24% weight loss equals approximately 60 pounds, bringing them to roughly 190 pounds. For a person starting at 200 pounds, that represents approximately 48 pounds of loss, reaching roughly 152 pounds. For a person starting at 300 pounds, it represents about 72 pounds, reaching roughly 228 pounds. It is important to emphasize that these are average figures derived from the 12 mg dose group in a 48-week trial. Individual results varied considerably around the mean — some participants lost more than 24%, while others lost less. Factors that may have influenced individual outcomes include baseline weight, metabolic health, adherence to the injection schedule, diet, physical activity, and genetic variation in drug response.

Realistic Expectations vs Social Media Hype

Social media posts claiming to show retatrutide before-and-after transformations should be viewed with extreme skepticism. Retatrutide is not commercially available and cannot be legally purchased outside of authorized clinical trials. Any individual claiming personal retatrutide results online is presenting unverifiable information — the substance they used may not be genuine retatrutide, the timeline may be inaccurate, or the images may be manipulated or attributed to a different intervention entirely. Individual responses to any weight loss medication vary substantially based on genetics, baseline metabolic health, diet, physical activity levels, starting weight, comorbidities, medication adherence, and numerous other factors. The 24.2% average in the Phase 2 trial is a population-level statistic representing the mean outcome across a group of participants — it is not a guarantee that any specific individual will achieve that exact result. Some participants in the trial lost significantly more, and some lost significantly less.

Comparison with Other GLP-1 Agonist Transformations

Because before-and-after documentation is well established for approved GLP-1 medications, comparing retatrutide’s Phase 2 data to proven results from marketed drugs provides useful context. Semaglutide (marketed as Wegovy for obesity) has produced approximately 15% average body weight loss in the pivotal STEP clinical trials, and real-world before-and-after outcomes are widely documented. Tirzepatide (marketed as Zepbound for obesity) achieved approximately 22% average weight loss in the Phase 3 SURMOUNT program. Retatrutide’s Phase 2 data suggests approximately 24% weight loss at the highest dose — modestly greater than tirzepatide and substantially greater than semaglutide. However, cross-trial comparisons carry inherent limitations because study populations, designs, inclusion criteria, and duration differ. The range of individual outcomes overlaps substantially across all three drugs, meaning that some semaglutide users lose more weight than some retatrutide users, and vice versa. Phase 3 data for retatrutide, when available, will provide a more definitive comparison.

• Semaglutide (Wegovy): ~15% average weight loss (Phase 3 STEP trials)
• Tirzepatide (Zepbound): ~22% average weight loss (Phase 3 SURMOUNT trials)
• Retatrutide: ~24% average weight loss at 12 mg (Phase 2 data)
• Cross-trial comparisons should be interpreted with caution due to study design differences
• Individual outcome ranges overlap substantially across all three medications

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References

1. Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial (2023) — PubMed
2. Retatrutide, a GIP, GLP-1 and Glucagon Receptor Agonist, for People with Type 2 Diabetes: A Randomised, Double-Blind, Placebo and Active-Comparator-Controlled, Parallel-Group, Phase 2 Trial (2023) — PubMed
3. Retatrutide Phase 2 Trial Results: Efficacy on Liver Fat Reduction in Participants with MASLD (2024) — PubMed
4. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1) (2021) — PubMed