Retatrutide weight loss results, trial by trial

8 trials have reported a body-weight outcome for Retatrutide. Each chart below is one trial, with every studied arm beside that trial’s placebo or comparator, at the timepoint the source reports. Retatrutide is investigational and not approved by the FDA or any other regulator. Eli Lilly has said it plans to submit a Biologics License Application to the FDA in the first quarter of 2027; no submission, priority review or decision date has been announced.

How to read these figures. They are group averages from selected trial populations under medical supervision. They do not predict any one person’s result. Trials differ in population, duration and how missing data were handled (the estimand), so a figure from one trial is never compared with a figure from another here, and sponsor topline releases are labelled as not yet peer-reviewed.

Research and educational reference only. Trial arms are the regimens studied under medical supervision, not an amount for anyone to take. Nothing here is medical advice.

TRIUMPH-1

NCT05929066 on ClinicalTrials.gov

Phase: Phase 3
Status: Completed
Population: Adults with obesity or overweight without type 2 diabetes (with knee osteoarthritis and sleep apnea substudies)
Randomized: 2,339
Duration: 80 weeks (24-week extension in participants with BMI ≥35)
Comparator: Placebo
Primary endpoint: Percent change in body weight at week 80

Arms as registered or published: Retatrutide 4 mg; Retatrutide 9 mg; Retatrutide 12 mg; Placebo (1:1:1:1)

Reported results

TRIUMPH-1: Mean % change in body weight, Week 80Treatment-regimen estimand (the paper’s primary analysis)

TRIUMPH-1: Mean % change in body weight at Week 80, by arm
Arm	Reported
Retatrutide 4 mg	−17.6%
Retatrutide 9 mg	−23.7%
Retatrutide 12 mg	−25.0%
Placebo(comparator)	−3.9%

Peer-reviewed publication: Jastreboff AM, et al. N Engl J Med 2026;395:1781-1793 (TRIUMPH-1)

Adverse events reported

TRIUMPH-1: adverse events by arm
Event	4 mg	9 mg	12 mg	Placebo
Nausea	28.6%	38.4%	42.4%	14.8%
Diarrhea	25.2%	34.1%	32.0%	13.5%
Constipation	23.8%	25.9%	26.1%	10.9%
Vomiting	10.6%	22.8%	25.3%	4.8%
Dysesthesia (altered skin sensation)	5.1%	12.3%	12.5%	0.9%
Stopped treatment because of adverse events	4.1%	6.9%	11.3%	4.9%

Percent of participants, as reported in Eli Lilly press release, 2026-05-21 (TRIUMPH-1 topline).

Adverse event rates are from Lilly’s 2026-05-21 topline release; Lilly’s medical-information page gives slightly different discontinuation figures from a later data cut.
In the 532 participants with BMI ≥35 who continued to week 104, the 12 mg arm reported −29.9% (treatment-regimen estimand) in the topline release.

Sources

Peer-reviewed publication: Jastreboff AM, et al. N Engl J Med 2026;395:1781-1793 (TRIUMPH-1) · PMID 42814954
Sponsor topline release (not peer-reviewed): Eli Lilly press release, 2026-05-21 (TRIUMPH-1 topline)
Trial registration: NCT05929066, ClinicalTrials.gov (checked 2026-11-08)

TRIUMPH-2

NCT05929079 on ClinicalTrials.gov

Phase: Phase 3
Status: Completed
Population: Adults with type 2 diabetes and obesity or overweight
Randomized: 1,152
Duration: 80 weeks
Comparator: Placebo
Primary endpoint: Percent change in body weight at week 80

Arms as registered or published: Retatrutide 4 mg (n=292); Retatrutide 9 mg (n=284); Retatrutide 12 mg (n=287); Placebo (n=289)

Reported results

TRIUMPH-2: Mean % change in body weight, Week 80Treatment-regimen estimand

TRIUMPH-2: Mean % change in body weight at Week 80, by arm
Arm	Reported	Analysed
Retatrutide 4 mg	−11.9%	n=292
Retatrutide 9 mg	−16.8%	n=284
Retatrutide 12 mg	−18.8%	n=287
Placebo(comparator)	−5.1%	n=289

Peer-reviewed publication: Bellido V, et al. Lancet 2026;408:1455-1472 (TRIUMPH-2)

Adverse events reported

TRIUMPH-2: adverse events by arm
Event	4 mg	9 mg	12 mg	Placebo
Diarrhea	27%	34%	34%	13%
Nausea	14%	21%	28%	8%
Dysesthesia	4%	6%	7%	1%
Hypotension	1%	5%	6%	<1%
Stopped treatment because of adverse events or death	4%	12%	8%	5%

Percent of participants, as reported in Bellido V, et al. Lancet 2026;408:1455-1472 (TRIUMPH-2).

Lilly’s 2026-07-23 topline release reported the efficacy estimand instead (−20.8% at 12 mg vs −4.0% placebo) and A1C changes the abstract does not give.

Sources

Peer-reviewed publication: Bellido V, et al. Lancet 2026;408:1455-1472 (TRIUMPH-2) · PMID 42810372
Sponsor topline release (not peer-reviewed): Eli Lilly press release, 2026-07-23 (TRIUMPH-2 and TRIUMPH-3 topline)
Trial registration: NCT05929079, ClinicalTrials.gov (checked 2026-11-08)

TRIUMPH-3

NCT05882045 on ClinicalTrials.gov

Phase: Phase 3
Status: Completed
Population: Adults with severe obesity and established cardiovascular disease
Randomized: 1,949
Duration: 80 weeks
Comparator: Placebo
Primary endpoint: Percent change in body weight at week 80

Arms as registered or published: Retatrutide 9 mg; Retatrutide 12 mg; Placebo (1:1:2)

Reported results

TRIUMPH-3: Mean % change in body weight, Week 80Efficacy estimand, from Lilly’s topline release (no peer-reviewed paper yet)

TRIUMPH-3: Mean % change in body weight at Week 80, by arm
Arm	Reported
Retatrutide 9 mg	−21.6%
Retatrutide 12 mg	−22.6%
Placebo(comparator)	−3.2%

Sponsor topline release (not peer-reviewed): Eli Lilly press release, 2026-07-23 (TRIUMPH-2 and TRIUMPH-3 topline)

Adverse events reported

TRIUMPH-3: adverse events by arm
Event	9 mg	12 mg	Placebo
Stopped treatment because of adverse events	9.8%	13.5%	4.8%

Percent of participants, as reported in Eli Lilly press release, 2026-07-23 (TRIUMPH-2 and TRIUMPH-3 topline).

Lilly also reported in-trial cardiovascular events pooled across retatrutide arms (MACE-5 hazard ratio 0.82, 95% CI 0.55 to 1.22). This is a weight trial, events were fewer than expected and the interval includes no effect: it is not cardiovascular outcome evidence. TRIUMPH-Outcomes is the trial designed for that.

Sources

Sponsor topline release (not peer-reviewed): Eli Lilly press release, 2026-07-23 (TRIUMPH-2 and TRIUMPH-3 topline)
Trial registration: NCT05882045, ClinicalTrials.gov (checked 2026-11-08)

TRIUMPH-4

NCT05931367 on ClinicalTrials.gov

Phase: Phase 3
Status: Completed
Population: Adults with obesity or overweight and knee osteoarthritis (84% with BMI ≥35)
Randomized: 445
Duration: 68 weeks
Comparator: Placebo
Primary endpoint: WOMAC pain and percent change in body weight at week 68

Arms as registered or published: Retatrutide 9 mg; Retatrutide 12 mg; Placebo (1:1:1)

Reported results

TRIUMPH-4: Mean % change in body weight, Week 68Treatment-regimen estimand, from Lilly’s topline release (no peer-reviewed paper yet)

TRIUMPH-4: Mean % change in body weight at Week 68, by arm
Arm	Reported
Retatrutide 9 mg	−20.0%
Retatrutide 12 mg	−23.7%
Placebo(comparator)	−4.6%

Sponsor topline release (not peer-reviewed): Eli Lilly press release, 2025-12-11 (TRIUMPH-4 topline)

Adverse events reported

TRIUMPH-4: adverse events by arm
Event	9 mg	12 mg	Placebo
Nausea	38.1%	43.2%	10.7%
Diarrhea	34.7%	33.1%	13.4%
Constipation	21.8%	25.0%	8.7%
Vomiting	20.4%	20.9%	0.0%
Dysesthesia	8.8%	20.9%	0.7%
Stopped treatment because of adverse events	12.2%	18.2%	4.0%

Percent of participants, as reported in Eli Lilly press release, 2025-12-11 (TRIUMPH-4 topline).

Lilly’s release gives NCT05869903 for this trial; that number belongs to a different Lilly trial (ATTAIN-1, orforglipron). The ClinicalTrials.gov record for TRIUMPH-4 is NCT05931367.
Mean baseline weight was 112.7 kg (BMI 40.4), heavier than in TRIUMPH-1.

Sources

Sponsor topline release (not peer-reviewed): Eli Lilly press release, 2025-12-11 (TRIUMPH-4 topline)
Trial registration: NCT05931367, ClinicalTrials.gov (checked 2026-11-08)

TRANSCEND-T2D-1

NCT06354660 on ClinicalTrials.gov

Phase: Phase 3
Status: Completed
Population: Adults with type 2 diabetes managed with diet and exercise
Randomized: 537
Duration: 40 weeks
Comparator: Placebo
Primary endpoint: HbA1c change at week 40

Arms as registered or published: Retatrutide 4 mg (n=134); Retatrutide 9 mg (n=133); Retatrutide 12 mg (n=136); Placebo (n=134)

Reported results

TRANSCEND-T2D-1: Mean % change in body weight, Week 40Treatment-regimen estimand

TRANSCEND-T2D-1: Mean % change in body weight at Week 40, by arm
Arm	Reported	Analysed
Retatrutide 4 mg	−11.5%	n=134
Retatrutide 9 mg	−13.9%	n=133
Retatrutide 12 mg	−15.3%	n=136
Placebo(comparator)	−2.6%	n=134

Peer-reviewed publication: Bajaj HS, et al. Lancet 2026;407:2402-2413 (TRANSCEND-T2D-1)

Stopping treatment because of adverse events was reported as 2–5% with retatrutide and 0% with placebo; no severe hypoglycemia.

Sources

Peer-reviewed publication: Bajaj HS, et al. Lancet 2026;407:2402-2413 (TRANSCEND-T2D-1) · PMID 42250575
Trial registration: NCT06354660, ClinicalTrials.gov (checked 2026-11-08)

TRANSCEND-T2D-2 (vs semaglutide)

NCT06260722 on ClinicalTrials.gov

Phase: Phase 3
Status: Active, not recruiting
Population: Adults with type 2 diabetes on metformin, with or without an SGLT2 inhibitor
Randomized: 1,298
Duration: 80 weeks
Comparator: Semaglutide 2 mg (Ozempic), open-label
Primary endpoint: HbA1c change at week 80 (noninferiority of 12 mg vs semaglutide 2 mg)

Arms as registered or published: Retatrutide 9 mg; Retatrutide 12 mg; Semaglutide (Ozempic) 2 mg (2:2:1)

Reported results

TRANSCEND-T2D-2 (vs semaglutide): Mean % change in body weight, Week 80Efficacy estimand only, from Lilly’s topline release (no peer-reviewed paper yet)

TRANSCEND-T2D-2 (vs semaglutide): Mean % change in body weight at Week 80, by arm
Arm	Reported
Retatrutide 9 mg	−19.5%
Retatrutide 12 mg	−20.9%
Semaglutide 2 mg(comparator)	−9.4%

Sponsor topline release (not peer-reviewed): Eli Lilly press release, 2026-10-28 (TRANSCEND-T2D-2 topline)

Adverse events reported

TRANSCEND-T2D-2 (vs semaglutide): adverse events by arm
Event	9 mg	12 mg	Semaglutide 2 mg
Stopped treatment because of adverse events	4.8%	7.9%	2.7%

Percent of participants, as reported in Eli Lilly press release, 2026-10-28 (TRANSCEND-T2D-2 topline).

The first randomized trial of retatrutide against another incretin medicine. It is open-label, in type 2 diabetes, and so far reported only as a press release using the efficacy estimand.
The registry still lists an estimated enrollment of 1,250; Lilly reports 1,298 randomized.

Sources

Sponsor topline release (not peer-reviewed): Eli Lilly press release, 2026-10-28 (TRANSCEND-T2D-2 topline)
Trial registration: NCT06260722, ClinicalTrials.gov (checked 2026-11-08)

Phase 2 obesity trial

NCT04881760 on ClinicalTrials.gov

Phase: Phase 2
Status: Completed
Population: Adults with obesity, or overweight with a weight-related condition, without diabetes
Enrolled: 338
Duration: 48 weeks
Comparator: Placebo
Primary endpoint: Percent change in body weight at week 24

Arms as registered or published: Retatrutide 1 mg; 4 mg (two starting schemes, combined); 8 mg (two starting schemes, combined); 12 mg; Placebo

Reported results

Phase 2 obesity trial: Mean % change in body weight, Week 48Efficacy estimand (least-squares mean)

Phase 2 obesity trial: Mean % change in body weight at Week 48, by arm
Arm	Reported
Retatrutide 1 mg	−8.7%
Retatrutide 4 mg	−17.1%
Retatrutide 8 mg	−22.8%
Retatrutide 12 mg	−24.2%
Placebo(comparator)	−2.1%

Peer-reviewed publication: Jastreboff AM, et al. N Engl J Med 2023;389:514-526

Adverse events reported

Phase 2 obesity trial: adverse events by arm
Event	Placebo	1 mg	4 mg (start 2)	4 mg (start 4)	8 mg (start 2)	8 mg (start 4)	12 mg
Nausea	11%	14%	18%	36%	17%	60%	45%
Diarrhea	11%	9%	12%	12%	20%	20%	15%
Vomiting	1%	3%	12%	12%	6%	26%	19%
Constipation	3%	7%	15%	6%	11%	11%	16%
Stopped treatment because of adverse events	0%	7%	6%	9%	14%	6%	16%

Percent of participants, as reported in Jastreboff AM, et al. N Engl J Med 2023;389:514-526.

Serious adverse events occurred in 4% of both the retatrutide and placebo groups. Heart rate rose with dose, peaked at week 24 and declined afterwards.
Skin sensitivity (cutaneous hyperesthesia) was reported in 7% on retatrutide and 1% on placebo.
Starting at 2 mg rather than 4 mg partly reduced gastrointestinal events, which is why later trials escalate gradually.

Sources

Peer-reviewed publication: Jastreboff AM, et al. N Engl J Med 2023;389:514-526 · PMID 37366315
Trial registration: NCT04881760, ClinicalTrials.gov (checked 2026-11-08)

Phase 2 type 2 diabetes trial

NCT04867785 on ClinicalTrials.gov

Phase: Phase 2
Status: Completed
Population: Adults with type 2 diabetes (HbA1c 7.0–10.5%, BMI 25–50) on diet and exercise or metformin
Randomized: 281
Duration: 36 weeks
Comparator: Placebo and dulaglutide 1.5 mg
Primary endpoint: HbA1c change at week 24

Reported results

Phase 2 type 2 diabetes trial: Mean % change in body weight, Week 36Least-squares mean, as reported in the abstract

Phase 2 type 2 diabetes trial: Mean % change in body weight at Week 36, by arm
Arm	Reported
Retatrutide 0.5 mg	−3.19%
Retatrutide 4 mg (escalated)	−7.92%
Retatrutide 4 mg	−10.37%
Retatrutide 8 mg (slow)	−16.81%
Retatrutide 8 mg (fast)	−16.34%
Retatrutide 12 mg	−16.94%
Placebo(comparator)	−3.0%
Dulaglutide 1.5 mg(comparator)	−2.02%

Peer-reviewed publication: Rosenstock J, et al. Lancet 2023;402:529-544

Mild-to-moderate gastrointestinal events: 35% on retatrutide overall (13% at 0.5 mg to 50% at 8 mg fast escalation), 13% on placebo, 35% on dulaglutide. No severe hypoglycemia and no deaths.

Sources

Peer-reviewed publication: Rosenstock J, et al. Lancet 2023;402:529-544 · PMID 37385280
Trial registration: NCT04867785, ClinicalTrials.gov (checked 2026-11-08)

Limits of this evidence

Cardiovascular and kidney outcomes: TRIUMPH-Outcomes (about 10,000 participants) is not expected to finish before 2029.
Long-term safety beyond 80–104 weeks, and rare adverse events that only a larger exposed population can show.
A blinded comparison with tirzepatide (TRIUMPH-5) and a peer-reviewed report of the semaglutide comparison.
What happens to weight after treatment stops, which TRIUMPH-6 is designed to test.
Dysesthesia (altered skin sensation) and heart-rate increases, both reported more often than with placebo and not yet fully characterized.