# Retatrutide Results in the Clinical Trials

> Retatrutide results from Phase 2 and Phase 3 trials: −24.2% body weight in obesity, −2.02% HbA1c in T2D, −82.4% liver fat in MASLD. Precise figures, every claim cited.

Phase 2 and Phase 3 efficacy and safety figures — obesity, type 2 diabetes, MASLD, and the growing discontinuation literature. Precise, cited, investigational.

## The short version

Retatrutide results from Phase 2 clinical trials show the largest weight reductions ever reported in a randomized drug trial: 24.2% mean body-weight reduction at 48 weeks at the highest dose [1]. Phase 3 data are now appearing: the first Phase 3 result in type 2 diabetes (TRANSCEND-T2D-1) confirms the signal with −15.3% body weight and −1.94% HbA1c at 40 weeks [12].

This page presents the retatrutide results precisely as the trials measured them. Every percentage, timepoint, and n-value is cited. The results also include the safety signals — because efficacy figures without safety context are half a picture — and the durability question: what the literature says about results after stopping, which is the defining open question for this compound class as of 2026.

## Obesity Phase 2 results (48 weeks)

Trial: NCT04644640. n=338 adults. BMI ≥30 or 27–<30 with comorbidity. No T2D. Once-weekly subcutaneous, 48 weeks [1].

| Dose | Mean body-weight change at 48 weeks |
|------|-------------------------------------|
| Placebo | −2.1% |
| 1 mg | −8.7% |
| 4 mg | −12.9% |
| 8 mg | −17.3% |
| 12 mg | −24.2% |

Secondary endpoints at 12 mg:
- Waist circumference: reduced approximately 19.6 cm.
- GI adverse events: nausea in up to 45%, dose-related, predominantly mild-to-moderate.
- Discontinuation due to AEs: 18% at 12 mg.
- Heart rate: dose-dependent increase, peaking approximately week 24.

A 2025 commentary characterizes the −24.2% figure as a step-change in the incretin-pharmacotherapy class — the largest weight reduction measured in a randomized drug trial to that point [6]. A 2024 review places the tri-agonist mechanism as the pharmacological basis for weight reductions approaching bariatric-surgery magnitude [11].

## Type 2 diabetes Phase 2 results (36 weeks)

Trial: NCT04867785. n=281 adults with T2D, inadequate control on background therapy. Once-weekly subcutaneous with stepwise escalation, 36 weeks [2].

Primary results at 12 mg:
- HbA1c change at 24 weeks: −2.02% versus −0.01% for placebo.
- Body weight at 36 weeks: −16.94% versus −3.00% for placebo.
- GI AEs: mild-to-moderate in 35%.
- Severe hypoglycemia: none. Deaths: none.

The glycemic efficacy (−2.02% HbA1c) is among the largest reported for any antidiabetic agent. The weight effect in the diabetic population (−16.94%) is numerically lower than the obesity Phase 2 result (−24.2%), consistent with the metabolic context of T2D.

## MASLD Phase 2a results (24–48 weeks)

Trial: NCT04881760 (substudy). n=98 participants with obesity/overweight and MASLD (≥10% liver fat by MRI-PDFF), without T2D. Once-weekly, 48 weeks [5].

Liver-fat reductions at 24 weeks by dose:
- 1 mg: −42.9%
- 4 mg: −57.0%
- 8 mg: −81.4%
- 12 mg: −82.4% (versus +0.3% for placebo)

At 12 mg, 86% of participants reached normal liver fat (<5%) by 24 weeks. Reductions were sustained and deepened to week 48 (−86.0% at 12 mg).

An incretin-therapy review identifies these liver-fat reductions as part of the broad cardiometabolic benefit profile of GIPR/GCGR/GLP-1R agonists [9].

## Phase 3: TRANSCEND-T2D-1 results (40 weeks)

Trial: NCT05929066 (TRANSCEND-T2D-1). n=537 adults with T2D inadequately controlled with diet and exercise. Retatrutide 12 mg versus placebo, 40 weeks [12].

Primary results:
- HbA1c: −1.94% (retatrutide 12 mg) versus −0.81% (placebo).
- Body weight: −15.3% versus −2.6%.
- Adverse events: predominantly mild-to-moderate GI; discontinuation due to AEs in 8.3% of the retatrutide arm.
- Severe hypoglycemia: none reported.

The TRANSCEND-T2D-1 results provide the first Phase 3 confirmation that the Phase 2 efficacy signal replicates. They are the first entry in the regulatory evidence package Eli Lilly will need for approval submissions.

## Retatrutide results after stopping: the durability record

No dedicated off-treatment follow-up trial for retatrutide has published results as of mid-2026. The durability question is answered, imperfectly, by the class literature.

A 2025 observational study documented substantial weight regain after interrupting liraglutide, semaglutide, and tirzepatide — all GLP-1-containing agents [7]. A 2026 review specifically identifies weight regain upon discontinuation as the principal limitation of the current incretin-therapy class, characterizes retatrutide's multi-receptor pharmacology as the most promising approach for improved durability, and acknowledges that clinical evidence for post-discontinuation durability advantage from the glucagon-receptor addition remains limited [13].

A mechanistic 2026 review of glucagon's role in obesity pharmacotherapy notes that the glucagon-receptor arm in triple agonists may theoretically drive more lasting metabolic adaptation through energy expenditure and hepatic lipid pathway changes — but frames this as a hypothesis requiring prospective data [15].

The TRIUMPH Phase 3 program includes trials designed to provide off-treatment follow-up. When those data are published, this page will reflect them. Until then, the retatrutide results record on discontinuation is: large Phase 2 on-treatment efficacy, open off-treatment question.

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A risograph broadside reading of the retatrutide Phase 2 and Phase 3 trial record — discontinuation, durability, and the stopping question set down precisely and cited to source, with no clinic and no prescription behind the charcoal stock.