Retatrutide Weight Loss Per Week
What clinical trial data actually shows — and why weekly averages can be misleading
Clinical trials do not report weekly weight loss figures. Based on Phase 2 data showing 24.2% mean weight loss over 48 weeks, a rough mathematical average is approximately 0.5% of body weight per week — but this is not a guaranteed or even typical rate. Weight loss is not linear: it is faster early in treatment and slows over time. Individual outcomes vary substantially. Retatrutide is not FDA-approved and is not commercially available.
Why Clinical Trials Don't Report Weekly Weight Loss
Clinical trials measure weight at defined assessment points — typically at weeks 4, 8, 12, 24, 48, 72, and 80 — rather than weekly. This is because:
Weight loss is not linear
The rate of weight loss changes over the course of treatment. It is typically fastest in the first 12–24 weeks as the drug reaches steady state and appetite suppression is strongest. The rate then slows as the body adapts and approaches a new equilibrium.
Week-to-week fluctuations are noise
Body weight fluctuates daily due to hydration, food intake, and other factors. Weekly measurements would reflect this noise rather than meaningful fat loss trends. Longer assessment intervals smooth out these fluctuations.
A weekly average implies a steady rate
Dividing total weight loss by weeks implies that weight loss happens at a constant rate — which it does not. Presenting a "per week" figure would be misleading about the actual pattern of weight change.
What the Data Actually Shows
The most complete published dataset comes from the Phase 2 trial (NCT04881760) published in the New England Journal of Medicine in 2023. For the 12 mg dose group:
The Phase 2 data also showed that the weight loss curve had not plateaued at 48 weeks in the highest dose groups — meaning participants were still losing weight at the end of the study. This is consistent with the Phase 3 extension data showing continued loss from 80 to 104 weeks.
For the complete dose-level breakdown and full trial data, see the retatrutide weight loss results page.
Why Individual Results Vary
Clinical trial averages describe what happened to a group of participants. Within any dose group, individual weight loss ranged widely. Factors that influence how quickly and how much weight a person loses include:
Frequently Asked Questions
How much weight can you lose per week on retatrutide?
Clinical trials do not report weekly weight loss figures. Based on Phase 2 data showing 24.2% mean weight loss over 48 weeks, a rough mathematical average is approximately 0.5% of body weight per week — but this is not a guaranteed rate. Weight loss is not linear: it is typically faster in the first weeks and slows as the body adapts. Individual outcomes vary substantially.
Why don't clinical trials report weekly weight loss?
Clinical trials measure weight at defined assessment points (e.g., weeks 4, 8, 12, 24, 48, 72, 80) rather than weekly. Reporting a weekly average would imply a steady, predictable rate that does not reflect how weight loss actually works — it is faster early, slower later, and varies between individuals.
Is weight loss on retatrutide linear?
No. Based on GLP-1 receptor agonist pharmacology and the Phase 2 dose-response data, weight loss is typically faster in the first 12–24 weeks and slows as the body reaches a new equilibrium. The Phase 2 data showed the weight loss curve had not plateaued at 48 weeks in the highest dose groups, suggesting continued loss with longer treatment.
How does retatrutide weight loss compare to tirzepatide per week?
Tirzepatide (Zepbound) produced approximately 20–22% mean weight loss over 72 weeks in SURMOUNT-1. Retatrutide produced 28.3% over 80 weeks in Phase 3 TRIUMPH-1. These are different trials with different durations and populations — a direct per-week comparison is not valid. No head-to-head randomized trial has been published.
What factors affect how fast someone loses weight on retatrutide?
Key factors include: starting body weight (heavier individuals often lose more absolute weight), dose level (higher doses produced more weight loss in Phase 2), adherence to the dosing schedule, diet and physical activity, individual metabolic response, and whether the person has type 2 diabetes (which is associated with lower weight loss on GLP-1 drugs).
Can I use trial averages to predict my own weekly weight loss?
No. Clinical trial averages describe what happened to a group of participants under controlled conditions. They cannot predict individual outcomes. Some participants in Phase 2 lost significantly more than the mean; others lost less or did not respond. Individual biology, lifestyle, and adherence all affect results.
Is retatrutide available to use right now?
No. Retatrutide is not FDA-approved and is not commercially available. The only legal way to access retatrutide is through an authorized clinical trial. Products sold online as "retatrutide" are not the pharmaceutical-grade compound used in clinical trials.