# Not Losing Weight on Tirzepatide? What Trials Show Source: https://www.philippinespeptides.com/faq/not-losing-weight Updated: 2026-10-01 > What the SURMOUNT trials reported for tirzepatide, why weight loss slows, what happened when treatment stopped, and why dose decisions sit with a physician. On this page - [What the trials reported](#trials) - [Why weight loss slows](#causes) - [When to see a physician](#help) - [FAQ](#faq) - [Sources](#sources) - [Related guides](#related) Faq · Plateaus # Not Losing Weight on Tirzepatide? Philippines Peptides editorial desk Updated 1 October 2026 4 min read **Topic** - Weight-loss plateaus **Compound** - Tirzepatide **Evidence** - Phase 3 human ## What the Trials Reported SURMOUNT-1 **Outcome.** In SURMOUNT-1, a 72-week phase 3 trial of 2,539 adults with BMI of 30 or more, or 27 or more with at least one weight-related complication, excluding diabetes, body weight fell by 15%, 19.5% and 20.9% on the 5 mg, 10 mg and 15 mg arms, against 3.1% on placebo. **Side effects reported in SURMOUNT-1.** Discontinuation for adverse events: 4.3%, 7.1% and 6.2% on the 5, 10 and 15 mg arms, against 2.6% on placebo. SURMOUNT-4 **Outcome.** In SURMOUNT-4, an 88-week phase 3 trial of 670 adults with BMI of 30 or more, or 27 or more with a weight-related complication, excluding diabetes, body weight changed by -5.5% on the Continued tirzepatide, weeks 36 to 88 arm, against 14% on switched to placebo. **Side effects reported in SURMOUNT-4.** Discontinuation for adverse events: 1.8% on the Continued tirzepatide, weeks 36 to 88 arm, against 0.9% on switched to placebo. Diarrhoea: 10.7% on the Continued tirzepatide, weeks 36 to 88 arm, against 4.8% on switched to placebo. Nausea: 8.1% on the Continued tirzepatide, weeks 36 to 88 arm, against 2.7% on switched to placebo. Vomiting: 5.7% on the Continued tirzepatide, weeks 36 to 88 arm, against 1.2% on switched to placebo. These figures are trial averages, and individual results in the SURMOUNT trials varied around them. The results describe Eli Lilly's registered medicine. They say nothing about research-grade material, whose content is known only from a laboratory report for that batch. ## Why Weight Loss Slows **Energy expenditure falls with body weight.** A smaller body uses less energy, and studies of large weight loss have measured a fall in resting energy expenditure beyond what the lost weight alone predicts (Fothergill 2016, S-04). **Appetite hormones shift and stay shifted.** After diet-induced weight loss, hormones that regulate appetite changed in a direction that favours regain and remained changed a year later (Sumithran 2011, S-03). **Stopping treatment reverses much of the loss.** In SURMOUNT-4, participants switched to placebo regained weight while those who continued tirzepatide kept losing, as set out above (S-02). ## When to See a Physician Caution The compound itself is covered in the [tirzepatide guide](https://www.philippinespeptides.com/peptides/tirzepatide), and the registered medicine, its availability and its price in the Philippines in the [Mounjaro guide](https://www.philippinespeptides.com/guides/mounjaro-philippines). ## FAQ ### Why does weight loss on tirzepatide slow or stop? Trial results are averages, and individual results in the SURMOUNT trials varied. In SURMOUNT-1, a 72-week phase 3 trial of 2,539 adults with BMI of 30 or more, or 27 or more with at least one weight-related complication, excluding diabetes, body weight fell by 15%, 19.5% and 20.9% on the 5 mg, 10 mg and 15 mg arms, against 3.1% on placebo. As body weight falls, energy expenditure falls with it and appetite-regulating hormones shift, which slows further loss (Fothergill 2016; Sumithran 2011). Tirzepatide is a prescription medicine, and prescribing belongs with a licensed Philippine physician; any question about response or dose belongs with the prescriber. ### What happened when tirzepatide was stopped in the trials? SURMOUNT-4 tested exactly this. In SURMOUNT-4, an 88-week phase 3 trial of 670 adults with BMI of 30 or more, or 27 or more with a weight-related complication, excluding diabetes, body weight changed by -5.5% on the Continued tirzepatide, weeks 36 to 88 arm, against 14% on switched to placebo. On average, participants switched to placebo regained weight. ## Sources - S-01 Trial [Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1)](https://www.nejm.org/doi/full/10.1056/NEJMoa2206038)Jastreboff AM, Aronne LJ, Ahmad NN, et al. · New England Journal of Medicine 387(3):205-216 · 2022 - S-02 Trial [Continued Treatment With Tirzepatide for Maintenance of Weight Reduction in Adults With Obesity (SURMOUNT-4)](https://doi.org/10.1001/jama.2023.24945)Aronne LJ, Sattar N, Horn DB, et al. · JAMA 331(1):38-48 · 2024 - S-03 Mechanism [Long-term persistence of hormonal adaptations to weight loss](https://www.nejm.org/doi/full/10.1056/NEJMoa1105816)Sumithran P, Prendergast LA, Delbridge E, et al. · New England Journal of Medicine 365(17):1597-1604 · 2011 - S-04 Mechanism [Persistent metabolic adaptation 6 years after "The Biggest Loser" competition](https://onlinelibrary.wiley.com/doi/10.1002/oby.21538)Fothergill E, Guo J, Howard L, et al. · Obesity (Silver Spring) 24(8):1612-1619 · 2016 - S-05 Reference [FDA Philippines: Verification Portal for Registered Drug Products](https://verification.fda.gov.ph)Food and Drug Administration of the Philippines · verification.fda.gov.ph · 2026 Trial figures and adverse events are read from the trials dataset published by our partner and supplier at primaralabs.com/research/trials, each row linked to its primary source. ## Related guides --- Philippines Peptides sells nothing. Primara Labs is our partner and supplier. This is general information, not medical or legal advice.