Tirzepatide and Type 2 Diabetes: What the Human Trials Found
Weight Loss & Metabolism Research
In type 2 diabetes, tirzepatide lowered HbA1c by 1.93 to 2.8 percentage points across six randomised trials, more than insulin degludec, insulin glargine, insulin lispro, dulaglutide, semaglutide or placebo, and body weight fell where on insulin it rose. Here is the tirzepatide type 2 diabetes record in one place: blood sugar, time in range, normal-range HbA1c, weight, kidneys, the heart and young people. For liver fat and other GLP-1 options, see GLP-1 for diabetes.
View product →Findings
- HbA1c fell further than on insulin. Against insulin degludec, insulin glargine and insulin lispro, 68% to 93% of tirzepatide participants reached an HbA1c below 7% (Lancet 2021, Nature Medicine 2023, JAMA 2023).
- Weight went down while insulin added it: tirzepatide groups lost 5.0 to 12.9 kg in those trials; the insulin groups gained 1.5 to 3.2 kg.
- 60.6% reached a normal-range HbA1c (below 5.7%) after 52 weeks in a pooled analysis of 912 adults in Japan (Diabetes Obes Metab, 2024).
- Major kidney events were 23% lower than on dulaglutide over a median 4.0 years in 13,299 adults with type 2 diabetes and atherosclerotic cardiovascular disease (Lancet Diabetes Endocrinol, 2026).
- Young people responded too: in 99 participants aged 10 to 17, HbA1c fell 2.23 points on tirzepatide and rose 0.05 on placebo (Lancet, 2025).
Tirzepatide and type 2 diabetes: two receptors
Tirzepatide is a once-weekly dual agonist of two gut-hormone (incretin) receptors: GIP, glucose-dependent insulinotropic polypeptide, and GLP-1, glucagon-like peptide-1. Semaglutide and dulaglutide act on the GLP-1 receptor alone. That is why tirzepatide has been tested against GLP-1 drugs as well as against insulin.
HbA1c: the tirzepatide type 2 diabetes trials
HbA1c, the standard long-term measure of blood sugar, was the main outcome in each trial. Falls are in percentage points; ranges cover the doses tested.
| Trial | Compared with | HbA1c fall |
|---|---|---|
| Lancet 2021, 1,444 adults | Insulin degludec | 1.93 to 2.37 vs 1.34 |
| JAMA 2023, 1,428 adults | Insulin lispro | 2.1 vs 1.1 |
| Nat Med 2023, 917 adults | Insulin glargine | 2.24 to 2.49 vs 0.95 |
| Lancet Diabetes Endocrinol 2022, 636 adults | Dulaglutide | 2.4 to 2.8 vs 1.3 |
| N Engl J Med 2021, 1,879 adults | Semaglutide | 2.01 to 2.30 vs 1.86 |
| Lancet 2025, 99 aged 10 to 17 | Placebo | 2.23 vs a 0.05 rise |
Against insulin. In the 2021 Lancet trial, 1,444 adults on metformin, with or without an SGLT2 inhibitor, started from an average HbA1c of 8.17%; after 52 weeks, 82% to 93% of the tirzepatide groups were below 7%, against 61% on insulin degludec. In the 2023 JAMA trial, 1,428 adults already on basal insulin added tirzepatide or mealtime insulin lispro to insulin glargine: average HbA1c went from 8.8% to 6.7% with tirzepatide and to 7.7% with insulin lispro. In 917 adults in China, South Korea, Australia and India, 75.4% to 86.0% reached below 7% on tirzepatide at 40 weeks, against 23.7% on insulin glargine (Nature Medicine, 2023).
Low blood sugar. Despite the larger HbA1c falls, low blood sugar (below 54 mg/dL, about 3.0 mmol/L, or severe) was less frequent than on insulin: 1% to 2% of participants against 7% on insulin degludec, and 0.4 against 4.4 events per patient-year in the insulin lispro trial. The most common side effects were gastrointestinal, mostly mild to moderate.
Against GLP-1 drugs. In Japan, 636 adults who were new to treatment or had stopped a single oral diabetes medicine saw HbA1c fall 2.4 to 2.8 points on tirzepatide over 52 weeks, against 1.3 on dulaglutide. Against semaglutide, in the 2021 New England Journal of Medicine head-to-head, tirzepatide was superior at every dose tested; the full comparison is in tirzepatide vs semaglutide.
Time in range on a glucose monitor
HbA1c is an average; a continuous glucose monitor shows the whole day. In a 243-person substudy of the 2021 insulin degludec trial, participants wore a monitor for about 7 days at baseline, 24 weeks and 52 weeks. At 52 weeks, the pooled higher-dose tirzepatide groups spent more of the day in a tight range of 71 to 140 mg/dL (about 3.9 to 7.8 mmol/L) than the insulin degludec group, an estimated treatment difference of 25% of the time (Lancet Diabetes Endocrinol, 2022).
Reaching a normal-range HbA1c
The Japanese trials also tracked normoglycaemia, an HbA1c below 5.7%. Pooling 912 tirzepatide participants from two 52-week studies, 553 (60.6%) reached it. Lower starting HbA1c, lower BMI, a shorter time with diabetes and the two higher doses all predicted success, and 94% of those who started below 8% and lost at least 15% of their body weight reached the normal range (Diabetes Obes Metab, 2024).
Weight in people with type 2 diabetes
From an average of 94.3 kg, tirzepatide groups lost 7.5 to 12.9 kg over 52 weeks while the insulin degludec group gained 2.3 kg. Against insulin lispro, the figures were a 9.0 kg loss and a 3.2 kg gain. Against dulaglutide in Japan, tirzepatide groups lost 7.8% to 13.9% of body weight, against 0.7%. For trials designed around weight itself, see tirzepatide human trials: weight and diabetes.
Kidneys and heart
Kidneys. In a post-hoc analysis of 2,002 adults with type 2 diabetes and high cardiovascular risk, kidney filtration (eGFR) declined by 1.4 mL/min/1.73 m² a year on tirzepatide against 3.6 on insulin glargine; urine albumin (UACR) rose 36.9% on insulin glargine but not on tirzepatide (Lancet Diabetes Endocrinol, 2022). In the cardiovascular outcomes trial, 13,299 adults with type 2 diabetes and atherosclerotic cardiovascular disease were randomised to tirzepatide or dulaglutide. Over a median 4.0 years, major kidney events were 23% lower on tirzepatide (6.0% against 7.6%, hazard ratio 0.77), and eGFR declined more slowly (Lancet Diabetes Endocrinol, 2026).
Heart. In the same trial (average age 64.1, 14.7 years with diabetes), tirzepatide met its noninferiority goal against dulaglutide, a GLP-1 drug already shown to reduce cardiovascular events: cardiovascular death, heart attack or stroke occurred in 12.2% against 13.1% (hazard ratio 0.92), a difference that did not reach statistical significance for superiority (N Engl J Med, 2025).
Tirzepatide in young people with type 2 diabetes
In a 2025 Lancet trial, 99 participants aged 10 to 17 (average age 14.7, baseline HbA1c 8.04%) on metformin, basal insulin or both received tirzepatide or placebo for 30 weeks. HbA1c fell 2.23 points on tirzepatide and rose 0.05 on placebo, BMI fell 7.4% and 11.2% on the two doses against 0.4%, and the HbA1c effect held to 52 weeks in an open-label extension.
Where reta (GLP-3) fits
Reta (GLP-3) adds a third receptor, glucagon, to the GIP and GLP-1 pair; the two are compared in reta vs tirzepatide.
Tirzepatide at Vistara Labs
Our tirzepatide is supplied as lyophilised vials with a certificate of analysis, shipped from within Canada; more in buy tirzepatide in Canada. The tirzepatide reconstitution guide covers bacteriostatic water, and the peptide calculator does the arithmetic.
Tirzepatide and reta (GLP-3) are supplied for laboratory research use only. For more, browse Weight Loss & Metabolism Research.
Frequently asked questions
What has research on tirzepatide in type 2 diabetes shown?
In six randomised trials, tirzepatide lowered HbA1c by 1.93 to 2.8 percentage points, more than insulin degludec, insulin glargine, insulin lispro, dulaglutide, semaglutide or placebo, while body weight fell.
What has tirzepatide research shown on HbA1c compared with insulin?
Against insulin degludec, insulin glargine and insulin lispro, 68% to 93% of tirzepatide participants reached an HbA1c below 7% and weight fell instead of rising. In the insulin degludec and insulin lispro trials, low blood sugar was also less frequent on tirzepatide.
What has research shown on tirzepatide, the kidneys and the heart?
In 13,299 adults with type 2 diabetes and atherosclerotic cardiovascular disease, major kidney events were 23% lower than on dulaglutide over a median 4.0 years, and tirzepatide met its noninferiority goal for cardiovascular death, heart attack or stroke.
What has tirzepatide research shown in young people with type 2 diabetes?
In 99 participants aged 10 to 17, HbA1c fell 2.23 points on tirzepatide against a 0.05 point rise on placebo at 30 weeks, and the effect held to 52 weeks.
Where can I buy tirzepatide in Canada?
Vistara Labs supplies tirzepatide as lyophilised vials with a certificate of analysis, alongside reta (GLP-3), shipped from within Canada. Laboratory research use only.
Product details from vistaralabs.ca, October 2026. Trial names are omitted from the titles below. Sources: Ludvik B et al. Once-weekly tirzepatide versus once-daily insulin degludec as add-on to metformin with or without SGLT2 inhibitors in patients with type 2 diabetes: a randomised, open-label, parallel-group, phase 3 trial. Lancet. 2021. PMID 34370970. Rosenstock J et al. Tirzepatide vs insulin lispro added to basal insulin in type 2 diabetes: a randomized clinical trial. JAMA. 2023. PMID 37786396. Gao L et al. Tirzepatide versus insulin glargine as second-line or third-line therapy in type 2 diabetes in the Asia-Pacific region. Nat Med. 2023. PMID 37231074. Inagaki N et al. Efficacy and safety of tirzepatide monotherapy compared with dulaglutide in Japanese patients with type 2 diabetes: a phase 3 trial. Lancet Diabetes Endocrinol. 2022. PMID 35914543. FrÃas JP et al. Tirzepatide versus semaglutide once weekly in patients with type 2 diabetes. N Engl J Med. 2021. PMID 34170647. Battelino T et al. Efficacy of once-weekly tirzepatide versus once-daily insulin degludec on glycaemic control measured by continuous glucose monitoring in adults with type 2 diabetes. Lancet Diabetes Endocrinol. 2022. PMID 35468321. Fujihara K et al. Achieving normoglycaemia with tirzepatide: post hoc exploratory analysis of two Japanese phase 3 studies. Diabetes Obes Metab. 2024. PMID 39192522. Heerspink HJL et al. Effects of tirzepatide versus insulin glargine on kidney outcomes in type 2 diabetes: post-hoc analysis of a phase 3 trial. Lancet Diabetes Endocrinol. 2022. PMID 36152639. Zoungas S et al. A comparison of the effects of tirzepatide and dulaglutide on major kidney events in people with type 2 diabetes. Lancet Diabetes Endocrinol. 2026. PMID 42114520. Nicholls SJ et al. Cardiovascular outcomes with tirzepatide versus dulaglutide in type 2 diabetes. N Engl J Med. 2025. PMID 41406444. Hannon TS et al. Efficacy and safety of tirzepatide in children and adolescents with type 2 diabetes: a randomised, double-blind, placebo-controlled, phase 3 trial. Lancet. 2025. PMID 40975112.
References
Tirzepatide has one of the largest human trial programmes of any compound in this catalogue, including multiple phase 3 trials.
- Tirzepatide Once Weekly for the Treatment of ObesityRandomised phase 3 trial; 2,539 adults with overweight or obesity without diabetes, 72 weeks.
- Continued Treatment With Tirzepatide for Maintenance of Weight Reduction in Adults With ObesityRandomised phase 3 withdrawal trial; 670 participants randomised after a 36-week open-label phase.
- Tirzepatide for the Treatment of Obstructive Sleep Apnea and ObesityRandomised phase 3 trials in adults with obesity and moderate-to-severe obstructive sleep apnoea.
- Tirzepatide for Heart Failure with Preserved Ejection Fraction and ObesityRandomised phase 3 trial (SUMMIT); 731 patients with obesity-related heart failure with preserved ejection fraction.
- Tirzepatide, cardiovascular outcomes and mortality in obesity and diabetes: a systematic review and meta-analysisSystematic review and meta-analysis; 22 trials, 29,023 participants.
Links open the study record on PubMed so the source can be checked directly. Listing a study is not a claim that its findings apply to any other use, product or route of administration. Research use only.
