SHEET 009 — Trial outcomes
Retatrutide Results in the Clinical Trials
Weight loss, HbA1c reduction, liver fat, kidney markers — every figure from the published Phase 1 and Phase 2 record, cited to its source.
What the results show — the plain version
Retatrutide is an investigational compound in Phase 3 trials. The results on this page come from Phase 1 and Phase 2 clinical trials — the human studies that tested whether it works and how well it is tolerated. These are real measured findings from controlled trials, not estimates or projections.
The headline finding: in a 48-week trial in people with obesity, the highest dose studied produced a mean -24.2% reduction in body weight versus -2.1% with placebo [1]. That is the single largest mean weight reduction ever reported in a Phase 2 obesity trial for a pharmaceutical agent. In separate trials: blood sugar markers improved substantially in type 2 diabetes participants [2]; liver fat fell by more than 80% in people with fatty liver disease [5]; and kidney markers showed favorable changes in both obesity and diabetes populations [11]. These retatrutide results are why the compound has generated so much attention.
Weight loss: Phase 2 obesity trial (48 weeks)
The pivotal Phase 2 obesity trial enrolled 338 adults (BMI 30 or above, or 27–30 with a weight-related health condition) and randomized them to weekly subcutaneous doses of 1, 4, 8, or 12 mg, or placebo, for 48 weeks [1].
Mean body-weight change at 48 weeks by dose:
- 1 mg: -8.7% (placebo: -2.1%)
- 4 mg: -17.3% (placebo: -2.1%)
- 8 mg: -22.8% (placebo: -2.1%)
- 12 mg: -24.2% (placebo: -2.1%)
At 12 mg, 63% of participants achieved at least 20% total body weight loss by week 48 [13]. The weight-loss curve had not plateaued by the trial end, suggesting additional efficacy at longer durations [1][6].
The 2025 review in Biomolecules characterizes the ~24% weight loss figure as a step-change in obesity pharmacology relative to prior incretin agents [6]. The 2025 systematic review across 53 phase 2/3 obesity trials confirms retatrutide's Phase 2 results as the highest published mean percentage weight loss in the field [9].
Type 2 diabetes: glycemic and weight outcomes
The Phase 2 diabetes trial enrolled 281 adults with type 2 diabetes and studied doses up to 12 mg over 36 weeks [2].
- HbA1c at 24 weeks: -2.02% at 12 mg vs -0.01% placebo [2]
- Body weight at 36 weeks: -16.94% at 12 mg vs -3.00% placebo [2]
- GI adverse events: 35% of participants; no severe hypoglycemia; no deaths [2]
The 2025 Cardiology in Review analysis of cardiovascular-kidney-metabolic syndrome data reports HbA1c reduction of 2.02% in T2D and significant attenuation of UACR across the combined Phase 2 dataset [13].
Liver fat: MASLD substudy results
The Phase 2a MASLD substudy enrolled 98 participants with confirmed liver fat of at least 10% (by MRI-PDFF) and no diabetes [5].
Relative liver-fat change at week 24:
- 1 mg: -42.9% vs +0.3% placebo
- 4 mg: -57.0%
- 8 mg: -81.4%
- 12 mg: -82.4%
At 12 mg, 86% of participants reached normal liver fat (below 5%) by week 24. At week 48, liver-fat reduction deepened to -86.0% at 12 mg [5]. This is the first Phase 2 liver-fat dataset for retatrutide; Phase 3 MASLD data are pending.
Kidney outcomes: Phase 2 substudy and meta-analysis
The kidney-renal angle is the lens of this site, and the data are the most recently published in the retatrutide record.
The 2025 Kidney International Reports substudy measured kidney markers in Phase 2 participants [11]:
- UACR reduction in T2D group (12 mg): approximately -37% vs placebo
- UACR reduction in obesity group (8–12 mg): approximately -28–31% vs placebo
- eGFR change in obesity group: +5.3–8.5 mL/min/1.73m²
The 2025 Maedica systematic review and meta-analysis specifically in CKD-comorbid patients found significant glycemic and weight reduction, with lower doses (8 mg or below) showing greater HbA1c benefit and a renoprotective signal via albuminuria reduction [14]. The 2026 Cardiology in Review CKM syndrome review confirmed significant attenuation of UACR alongside the 24.2% weight loss and HbA1c figures from the combined Phase 2 record [13].
The TRANSCEND-CKD Phase 3 trial — the dedicated renal outcomes study — will provide the definitive kidney evidence; its design and baseline characteristics were published in 2025 [12].
Phase 1b: first human efficacy signal
The Phase 1b trial in 72 adults with type 2 diabetes over 12 weeks was the first-in-human study [4]. Placebo-adjusted weight loss at the highest dose group was -8.96 kg (90% CI -11.16 to -6.75) over 12 weeks. Daily blood glucose fell 2.8 mmol/L at 3 mg [4]. The half-life of approximately 6 days was confirmed, establishing the pharmacokinetic rationale for once-weekly dosing [4]. Treatment-emergent adverse events occurred in 63% of participants, mostly GI.
For the full Retatrutide research record, see the research page. For information on how the compound produces these results, see how does retatrutide work.