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The dad-test answer
Both are made by Eli Lilly, both treat Type 2 diabetes, and the head-to-head is decisive. Mounjaro (tirzepatide) is the dual GIP/GLP-1 agonist; Trulicity (dulaglutide) is the older GLP-1-only molecule. Mounjaro produces about 2-3x the weight loss and a meaningfully larger A1C drop than Trulicity at maximum doses. Trulicity is older and cheaper; Mounjaro is the heavier hitter. SURPASS-CVOT confirmed cardiovascular non-inferiority in 2025.
Who wins for what
| Use case | Who wins, and why |
|---|---|
| A1C reduction in Type 2 diabetes |
tirzepatide SURPASS-CVOT and earlier trials show A1C drop 1.66% on tirzepatide vs 0.88% on dulaglutide at maximum doses. |
| weight loss as a side benefit |
tirzepatide Same trials: weight loss 11.6% on tirzepatide vs 4.5% on dulaglutide - a 2-3x gap that's beyond rounding error. |
| cardiovascular outcomes |
tirzepatide (slight) SURPASS-CVOT (NEJM 2025): MACE 12.2% on tirzepatide vs 13.1% on dulaglutide - non-inferior; all-cause mortality 8.6% vs 10.2% favoring tirzepatide. |
| established cost / insurance / older record |
dulaglutide Trulicity launched in 2014 with deeper formulary acceptance, generic alternatives appearing, and a longer real-world track record. |
What the head-to-head data shows
Both are FDA-approved for Type 2 diabetes; Trulicity (dulaglutide) was approved in 2014, Mounjaro (tirzepatide) in 2022. The head-to-head evidence is comprehensive. SURPASS-2 (Frias et al., NEJM 2021) compared tirzepatide vs semaglutide; SURPASS-CVOT (NEJM 2025) is the cardiovascular outcomes trial directly comparing tirzepatide vs dulaglutide in 13,000+ patients with Type 2 diabetes and atherosclerotic cardiovascular disease over a median 4-year follow-up. Primary MACE endpoint (cardiovascular death, MI, stroke) occurred in 12.2% of tirzepatide patients vs 13.1% of dulaglutide patients (HR 0.92; non-inferiority met; superiority p=0.09). All-cause mortality was reduced on tirzepatide (8.6% vs 10.2%), driven primarily by lower non-cardiovascular death. A1C reduction at maximum doses ran approximately 1.66% on tirzepatide vs 0.88% on dulaglutide; weight loss approximately 11.6% vs 4.5%. FDA Mounjaro approval (May 2022) and FDA Trulicity approval (Sep 2014) cover the regulatory path.
Our honest call
For a reader with Type 2 diabetes starting GLP-1 therapy in 2026, tirzepatide (Mounjaro) is the better default - the head-to-head A1C reduction is meaningfully larger, weight loss is 2-3x bigger, and SURPASS-CVOT confirmed cardiovascular safety is at least as good as dulaglutide with a mortality signal favoring tirzepatide. Trulicity remains a reasonable choice when insurance specifically covers it, when the patient has tolerated it well for years, or when the diabetes is well-controlled at low doses where the tirzepatide advantage is smaller. The pragmatic question for someone already on Trulicity: if A1C is at target and tolerability is good, the case to switch is weak. If A1C is above target or weight is the secondary concern, the switch to Mounjaro is supported by data. Read the main tirzepatide vs semaglutide page for the broader GLP-1 picture.
Sources and citations
- SURPASS-CVOT trial, NEJM 2025 (PMID 41406444)
- Frias et al., SURPASS-2 trial, NEJM 2021 (PMID 34170647)
- FDA Mounjaro prescribing label (approved May 2022)
- FDA Trulicity prescribing label (approved Sep 2014)
- Eli Lilly SURPASS clinical program registry
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Last reviewed · 2026-05-07 · Page generated by Protocol One matrix engine. None of this replaces a doctor. Peptides are gray-market in the US for most uses. Talk to a real prescriber before you change anything.