The evidence
Retatrutide clinical trial results
Eli Lilly's Phase 3 TRIUMPH program has produced the largest weight reductions ever recorded for a medication. Here is every major result, straight from the trials.
May 2026 · 2,339 participants · 80 weeks
TRIUMPH-1 — the landmark obesity trial
| Dose | Average weight lost | % body weight |
|---|---|---|
| Placebo | 5.5 lbs (2.5 kg) | 2.2% |
| 4 mg | 47.2 lbs (21.4 kg) | 19.0% |
| 9 mg | 64.4 lbs (29.2 kg) | 25.9% |
| 12 mg | 70.3 lbs (31.9 kg) | 28.3% |
0.0%
of participants on 12 mg achieved 30%+ body weight loss — a level previously only seen with bariatric surgery
0.0%
on 12 mg reached a BMI below 30 — no longer meeting the clinical definition of obesity
0.0%
reached a healthy BMI below 25
0 lbs
average loss (30.3% of body weight) in the 104-week extension study on 12 mg
Cardiovascular risk markers improved across the board:
Triglycerides down 41% · non-HDL cholesterol down 24.2% · systolic blood pressure down 12.3 mmHg.
December 2025 · 445 participants · 68 weeks
TRIUMPH-4 — obesity + knee osteoarthritis
- 71.2 lbs (32.3 kg) average weight loss on 12 mg — 28.7% of body weight
- Knee pain scores reduced by up to 75.8%
- 14.1% of participants on 9 mg were completely free of knee pain
- Physical function scores improved by up to 73.7%
June 2026 · 537 participants · 40 weeks
TRANSCEND-T2D-1 — type 2 diabetes
- HbA1c reduced by up to 2.0% from a 7.9% baseline
- 90% achieved an A1C below 7.0% — the ADA’s general diabetes target
- 46% reached A1C below 5.7% — the threshold for normal blood sugar
- Weight loss up to 36.6 lbs (16.6 kg) — and still declining at 40 weeks
TRIUMPH-1 basket study
Sleep apnoea results
- Apnoea-hypopnoea index (AHI) reduced by up to 36.1 events per hour
- A 60.6% reduction in sleep apnoea severity
- A potentially life-changing result for the millions of Australians living with obstructive sleep apnoea
What is retatrutide being studied for?
The road to approval
2023
Phase 2 results published in the New England Journal of Medicine — up to 24.2% weight loss.
Dec 2025
TRIUMPH-4 Phase 3 results — obesity with knee osteoarthritis.
Mar 2026
TRANSCEND-T2D-1 topline results — type 2 diabetes.
May 2026
TRIUMPH-1 Phase 3 results — the landmark obesity trial.
Jun 2026
Full data presented at the ADA Scientific Sessions and published in The Lancet.
2027
Eli Lilly plans to file for regulatory approval.
TBA
TGA review and potential approval in Australia.
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