Background Mazdutide, a dual glucagon-like peptide-1 (GLP-1) and glucagon receptor agonist, has shown promising metabolic benefits in randomized controlled trials (RCTs) of adults with type 2 diabetes mellitus (T2DM). However, its efficacy and safety have not been systematically synthesized. Objective To evaluate the efficacy and safety of mazdutide versus placebo in adults with T2DM. Methods A systematic review and meta-analysis of RCTs was conducted according to PRISMA 2020 guidelines. PubMed, Embase, Cochrane Library, and ScienceDirect were searched from inception through May 2026. Risk of bias was assessed using the Cochrane RoB 2 tool, and certainty of evidence was evaluated with the GRADE framework. Results Three RCTs involving 613 participants were included. Compared with placebo, mazdutide significantly reduced HbA1c (MD −1.53%; 95% CI −1.70 to −1.35), body weight (MD −4.22%; 95% CI −5.71 to −2.73), fasting plasma glucose, body mass index, waist circumference, blood pressure, and triglycerides. It also increased the likelihood of achieving HbA1c
Systematic Review
[version 1; peer review: awaiting peer review]
https://orcid.org/0009-0004-6101-6433
2, Aimen Farooqhttps://orcid.org/0009-0007-4185-495X
2, [...] Sajila Latifhttps://orcid.org/0009-0005-3299-4438
3, Minahil Rasulhttps://orcid.org/0009-0003-3830-136X
4, Shanza Abbasihttps://orcid.org/0009-0005-4220-3281
3, Amna Muhammad Alihttps://orcid.org/0009-0000-8166-1465
5, Eman Arshadhttps://orcid.org/0009-0000-8209-8934
2, Mohammad Azeem Malik2, Kawish Nenwanihttps://orcid.org/0009-0009-6887-0399
6, Intzar Ahmedhttps://orcid.org/0009-0001-4690-0325
7, Muhammad Sarmad2, Rohma Khanhttps://orcid.org/0009-0005-8311-9721
2, Sagar Kumar8, Abdul Haseeb Hasanhttps://orcid.org/0009-0004-9808-9054
9, Ahmad Hassan2https://orcid.org/0009-0004-6101-6433
2, [...] Aimen Farooqhttps://orcid.org/0009-0007-4185-495X
2, Sajila Latifhttps://orcid.org/0009-0005-3299-4438
3, Minahil Rasulhttps://orcid.org/0009-0003-3830-136X
4, Shanza Abbasihttps://orcid.org/0009-0005-4220-3281
3, Amna Muhammad Alihttps://orcid.org/0009-0000-8166-1465
5, Eman Arshadhttps://orcid.org/0009-0000-8209-8934
2, Mohammad Azeem Malik2, Kawish Nenwanihttps://orcid.org/0009-0009-6887-0399
6, Intzar Ahmedhttps://orcid.org/0009-0001-4690-0325
7, Muhammad Sarmad2, Rohma Khanhttps://orcid.org/0009-0005-8311-9721
2, Sagar Kumar8, Abdul Haseeb Hasanhttps://orcid.org/0009-0004-9808-9054
9, Ahmad Hassan21 Shaikh Khalifa Bin Zayed Al Nahyan Medical and Dental College, Lahore, Punjab, Pakistan
2 King Edward Medical University, Lahore, Punjab, Pakistan
3 Rawalpindi Medical University, Rawalpindi, Punjab, Pakistan
4 The University of Lahore University College of Medicine and Dentistry, Lahore, Punjab, Pakistan
5 Fatima Jinnah Medical University, Lahore, Punjab, Pakistan
6 Suleman Roshan Medical College, Tando Adam, Pakistan
7 Islam Medical College, Sialkot, Punjab, Pakistan
8 Khairpur Medical College, Khairpur, Sindh, Pakistan
9 Oli Health Magazine Organization Kigali, Kigali, Kigali City, Rwanda
Affaf Mahmood
Roles: Conceptualization, Data Curation, Investigation, Project Administration, Validation
Noor Us Sehar
Roles: Conceptualization, Data Curation, Formal Analysis
Aimen Farooq
Roles: Investigation, Methodology, Software
Sajila Latif
Roles: Data Curation, Software, Visualization
Minahil Rasul
Roles: Writing – Original Draft Preparation, Writing – Review & Editing
Shanza Abbasi
Roles: Investigation, Validation, Visualization
Amna Muhammad Ali
Roles: Methodology, Software
Eman Arshad
Roles: Data Curation, Investigation
Mohammad Azeem Malik
Roles: Methodology, Visualization
Kawish Nenwani
Roles: Formal Analysis, Methodology
Intzar Ahmed
Roles: Software, Validation
Muhammad Sarmad
Roles: Data Curation, Formal Analysis
Rohma Khan
Roles: Conceptualization, Writing – Review & Editing
Sagar Kumar
Roles: Investigation, Software
Abdul Haseeb Hasan
Roles: Validation, Visualization
Ahmad Hassan
Roles: Supervision
OPEN PEER REVIEW
REVIEWER STATUS AWAITING PEER REVIEW
Type 2 diabetes mellitus (T2DM) is one of the most prevalent chronic metabolic disorders worldwide and represents a major public health challenge. According to the International Diabetes Federation, approximately 589 million adults were living with diabetes globally in 2024, with this number projected to rise to 853 million by 2050.1 It is a progressive metabolic disorder characterized by chronic hyperglycemia resulting from insulin resistance and β-cell dysfunction.2
Management of T2DM involves a multifaceted approach incorporating lifestyle interventions and pharmacological therapies aimed at achieving glycemic control and reducing the risk of diabetes-related complications.3 Available treatment options include metformin, sulfonylureas, thiazolidinediones, DPP-4 inhibitors, SGLT2 inhibitors, GLP-1 receptor agonists, and insulin-based therapies.4 Despite substantial advances in treatment, many individuals with T2DM fail to achieve optimal glycemic control and remain at increased risk of cardiovascular, renal, and metabolic complications.3 Given the close relationship between obesity and T2DM, contemporary management strategies increasingly aim to improve both glycemic control and excess body weight.5
Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have emerged as an important therapeutic class due to their ability to lower glycated hemoglobin (HbA1c), promote weight loss, and reduce cardiometabolic risk.6 More recently, the development of multi-receptor agonists has expanded the therapeutic landscape of T2DM.7 Among these, dual GLP-1 and glucagon receptor agonists have attracted considerable interest because they combine the glucose-lowering and appetite-suppressing effects of GLP-1 receptor activation with the potential of glucagon receptor activation to increase energy expenditure and improve metabolic function.8,9
Mazdutide (IBI362/LY3305677) is a once-weekly dual GLP-1 and glucagon receptor agonist derived from oxyntomodulin.10 Through simultaneous activation of both receptors, mazdutide has been designed to improve glycemic control while providing additional benefits on body weight and cardiometabolic risk factors.11 Several randomized controlled trials (RCTs) have demonstrated favorable effects of mazdutide on HbA1c, fasting plasma glucose, body weight, and other metabolic outcomes in individuals with T2DM.12 Furthermore, emerging evidence suggests a generally acceptable safety profile, with gastrointestinal adverse events representing the most commonly reported treatment-related effects.12
Although individual RCTs have reported promising findings, the overall efficacy and safety of mazdutide in patients with T2DM have not been comprehensively synthesized. Previous evidence syntheses have primarily focused on obesity populations or evaluated mazdutide alongside other dual GLP-1/glucagon receptor agonists, limiting the ability to draw conclusions regarding the specific effects of mazdutide in T2DM.13,14
Therefore, we conducted a systematic review and meta-analysis of randomized controlled trials to evaluate the efficacy and safety of mazdutide in adults with T2DM. Additionally, a GRADE assessment was performed to determine the certainty of the available evidence across clinically relevant efficacy and safety outcomes.
This systematic review and meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines.15 The completed PRISMA 2020 checklist is available in the external repository. A comprehensive literature search was performed in PubMed, Embase, the Cochrane Library, and ScienceDirect from database inception through May 2026 to identify randomized controlled trials comparing mazdutide with placebo in patients with type 2 diabetes mellitus (T2DM). The search strategy incorporated both controlled vocabulary terms and free-text keywords related to mazdutide and placebo. The terms used included “Mazdutide,” “IBI362,” “LY3305677,” “GLP-1/glucagon receptor agonist,” “dual GLP-1 glucagon agonist,” “GLP-1 glucagon co-agonist,” “twincretin,” “IBI362,” “Glucagon like peptide 1 receptor agonist,” “Glucagon receptor agonist,” “GLP-1 agonist,” “Incretin agonist,” “Dual Incretin glucagon agonist,” and related synonyms. Database-specific search strategies were adapted as appropriate for each platform. The detailed search strategies for each database are provided in extended data in the external repository. Reference lists of relevant reviews and eligible studies were also screened manually to identify additional potentially eligible articles. No restrictions were applied regarding publication status, while only studies published in English were considered for inclusion.
Studies were included if they met the following criteria: (1) enrolled adult patients (≥18 years) diagnosed with type 2 diabetes mellitus (T2DM); (2) compared mazdutide, administered at any dose, frequency, or treatment duration, with placebo; (3) were randomized controlled trials (RCTs); (4) reported at least one efficacy outcome (e.g., glycated hemoglobin [HbA1c], fasting plasma glucose, body weight, waist circumference, or other metabolic parameters) or safety outcome (e.g., adverse events, serious adverse events, gastrointestinal adverse events, or treatment discontinuation); and (5) provided sufficient data for extraction and quantitative synthesis. Only studies published in the English language were considered.
Studies were excluded if they: (1) enrolled participants without T2DM; (2) did not directly compare mazdutide with placebo; (3) were non-randomized studies, observational studies, case reports, case series, reviews, editorials, conference abstracts without sufficient data, letters, or animal studies; (4) lacked relevant efficacy or safety outcomes; or (5) contained insufficient data for analysis.
All records retrieved from the electronic databases were imported into Zotero, where duplicate records were identified and removed prior to screening. Two reviewers independently screened the titles and abstracts of all retrieved studies according to the predefined eligibility criteria. The full texts of potentially eligible studies were then independently assessed by the same reviewers to determine their eligibility for inclusion. Any disagreements regarding study selection were resolved through discussion and consensus. If consensus could not be reached, a third reviewer was consulted to make the final decision. The study selection process was documented using the PRISMA 2020 flow diagram.
A structured Google Sheet was used for data extraction. A standardized data extraction form was developed to collect study-level information, including the first author’s name, year of publication, study design, sample size, duration of follow-up, intervention and comparator dosages, and baseline patient characteristics. Baseline characteristics extracted included age, sex, body mass index (BMI), duration of type 2 diabetes mellitus, glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), body weight, and other relevant clinical variables.
Outcome data were categorized into efficacy and safety endpoints. Primary efficacy outcomes included change from baseline (CFB) in HbA1c, the proportion of participants achieving HbA1c <7.0%, and CFB in body weight expressed as both percentage and absolute change (kg). Secondary efficacy outcomes included the proportions of participants achieving HbA1c ≤6.5% and <5.7%, CFB in FPG, proportions of participants achieving ≥5% and ≥10% weight loss, the proportion achieving both ≥5% weight loss and HbA1c <7.0%, CFB in BMI and waist circumference, measures of beta-cell function and insulin resistance (HOMA2-B and HOMA2-IR), cardiovascular parameters including systolic blood pressure (SBP), diastolic blood pressure (DBP), and lipid profile, hepatic parameters including alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and renal parameters including serum uric acid.
Safety outcomes were categorized as primary and secondary endpoints. The primary safety outcome was the incidence of treatment-emergent adverse events (TEAEs). Secondary safety outcomes included serious adverse events (SAEs), TEAEs leading to treatment discontinuation, gastrointestinal adverse events (diarrhea, nausea, vomiting, abdominal distention, and decreased appetite), systemic adverse events (asthenia), metabolic adverse events (hypoglycemia, hyperuricemia, and increased lipase), cardiovascular adverse events (tachycardia, bradycardia, atrioventricular block, and arrhythmia), allergic reactions (injection-site reactions and hypersensitivity), hepatobiliary events (cholecystitis and cholelithiasis), diabetic ketosis, and infectious complications including upper respiratory tract infections (URTIs) and urinary tract infections (UTIs).
Data extraction was performed independently by four reviewers using the predefined extraction form. The extracted data were subsequently reviewed and cross-checked by an additional group of four authors to ensure completeness, accuracy, and consistency. Any discrepancies were resolved through discussion and consensus among the investigators. The standardized data extraction sheet containing all extracted baseline characteristics and outcome data is available as a separate file in the external repository.
The methodological quality of the included randomized controlled trials was assessed using the Cochrane revised Risk of Bias tool for randomized trials (RoB 2).16 This tool evaluates potential sources of bias across five domains: bias arising from the randomization process, bias due to deviations from intended interventions, bias due to missing outcome data, bias in the measurement of outcomes, and bias in the selection of the reported results. Each domain was rated as “low risk of bias,” “some concerns,” or “high risk of bias,” and an overall risk-of-bias judgment was assigned for each study. Risk-of-bias assessments were conducted separately for efficacy and safety outcomes, recognizing that the risk profile may differ according to the outcome evaluated. The assessments were performed independently by two reviewers, and any disagreements were resolved through discussion and consensus. Risk-of-bias summary figures and traffic-light plots were generated to visually present the methodological quality of the included studies.
The certainty of evidence for the predefined efficacy and safety outcomes was evaluated independently by two reviewers using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework.17 The certainty of evidence for each outcome was categorized as high, moderate, low, or very low based on the domains of risk of bias, inconsistency, indirectness, imprecision, and publication bias. Randomized controlled trials were initially rated as high-certainty evidence and were downgraded where appropriate according to GRADE recommendations. Disagreements between reviewers were resolved through discussion or consultation with a third reviewer. A Summary of Findings (SoF) table was generated using GRADEpro GDT (McMaster University and Evidence Prime) and is provided in the extended data in external repository.
Statistical analyses were performed using Review Manager (RevMan) software. For dichotomous outcomes, effect sizes were calculated as odds ratios (ORs) with 95% confidence intervals (CIs), whereas continuous outcomes were summarized using mean differences (MDs) with corresponding 95% CIs. Heterogeneity among studies was assessed using the Cochrane Q test (Chi-square test) and quantified using the I2 statistic. An I2 value ≤50% with P ≥0.05 was considered to indicate low heterogeneity, and a fixed-effect model was applied in such cases. For outcomes with substantial heterogeneity (I2 >50% and P <0.05), a random-effects model was used to account for between-study variability, in accordance with established meta-analytic guidelines.
Predefined subgroup analyses were performed for all efficacy outcomes to explore potential sources of heterogeneity. These included dose-based subgroup analyses comparing 3 mg, 4/4.5 mg, and 6 mg mazdutide versus placebo, as well as treatment duration–based subgroup analyses stratified by follow-up duration of ≥20 weeks.
Sensitivity analyses were conducted to evaluate the robustness of the pooled results and to identify potential sources of heterogeneity. A leave-one-out approach was applied by sequentially excluding each study to assess its influence on the overall effect size. These analyses were performed only for outcomes demonstrating substantial statistical heterogeneity, defined as I2 >75%. The impact of individual studies on heterogeneity and pooled estimates was examined across these key high-heterogeneity outcomes to assess the stability of the results.
A total of 1,371 references were identified from four databases, namely PubMed, Cochrane, ScienceDirect, and Embase. After removal of 263 duplicate records, 1,108 records underwent title and abstract screening, of which 1,097 were excluded. Eleven reports underwent full-text evaluation, of which eight were excluded due to wrong comparison (n=6), insufficient data (n=1), and wrong outcome (n=1). Ultimately, three RCTs met the inclusion criteria and were included in the review. The PRISMA flowchart summarizing the process is shown in Figure 1.
All three included RCTs11,12,18 were conducted in Chinese adults with type 2 diabetes mellitus. One study was a phase 3 double-blind, placebo-controlled trial (DREAMS-1), one was a phase 2 double-blind, placebo-controlled, active-referenced trial, and one was a phase 1b randomized, placebo-controlled, multiple ascending-dose trial. A total of 613 participants, including placebo recipients, were enrolled across the three studies. All trials evaluated once weekly subcutaneous mazdutide (IBI362/LY3305677) at doses of 3mg, 4/4.5mg and 6mg compared with placebo. Treatment duration ranged from 12 to 24 weeks, with Zhu 2026 including an additional 24-week extension phase.
Baseline characteristics were generally comparable across the included studies. Participants were middle-aged adults with inadequately controlled type 2 diabetes mellitus. Mean HbA1c ranged from 7.94% to 8.9%, fasting plasma glucose from 9.2 to 11.7 mmol/L, and BMI from 24.1 to 28.6 kg/m2. Mean duration of diabetes ranged from 1.8 to 6.1 years. Background metformin use varied across studies, ranging from none reported in Zhu 2026 to 65–69% in Zhang 2024 and 38–58% in Jiang 2022. Baseline characteristics were well balanced between treatment groups within each study ( Table 1).
A total of 51 outcomes were evaluated and categorized into primary and secondary efficacy outcomes, as well as primary and secondary safety outcomes. Primary efficacy outcomes included glycemic and weight reduction parameters. Secondary efficacy outcomes included additional glycemic control outcomes, metabolic, anthropometric, beta-cell function, cardiovascular, hepatic, and renal biomarker outcomes. Treatment-emergent adverse events (TEAEs) were assessed as the primary safety outcome. Secondary safety outcomes included a broad range of gastrointestinal, cardiovascular, hepatobiliary, metabolic and other systemic adverse effects. A comprehensive list of all outcomes is presented in Table 2. The main manuscript presents the analyses of the following outcomes: HbA1c change from baseline (%), achievement of HbA1c <7.0%, body weight change from baseline (%), fasting plasma glucose change from baseline, participants achieving ≥5% and ≥10% weight loss, body mass index, waist circumference, HOMA2-B, HOMA2-IR, systolic and diastolic blood pressure, triglycerides, alanine aminotransferase, serum uric acid, treatment-emergent adverse events, severe treatment-emergent adverse events, serious adverse events, gastrointestinal adverse events (diarrhea, nausea, vomiting, abdominal distention, and decreased appetite), and cardiovascular adverse events (cardiac disorders, sinus tachycardia, and first-degree atrioventricular block). Subgroup analyses based on mazdutide dosage (3 mg, 4/4.5 mg, and 6 mg) and follow-up duration (12 weeks and ≥20 weeks) are also presented for these outcomes, where applicable. Forest plots for the remaining outcomes, including HbA1c change from baseline (mmol/mol), body weight change from baseline (kg), achievement of HbA1c ≤6.5% and <5.7%, the composite outcome of ≥5% weight loss with HbA1c <7.0%, total cholesterol, LDL cholesterol, HDL cholesterol, percentage changes in all lipid parameters, aspartate aminotransferase, systemic adverse events (asthenia and dizziness), metabolic adverse events (hyperuricaemia, hyperlipidemia, lipase increased, and hypoglycemia including Levels 1 and 2), injection-site reactions, hepatobiliary adverse events (hepatic function abnormal), and infectious adverse events (upper respiratory tract infection and urinary tract infection), are provided in the extended data and are not discussed in the main manuscript.
A. Primary efficacy outcomes:
A. PRIMARY EFFICACY OUTCOMES
B. SECONDARY EFFICACY OUTCOMES
C. PRIMARY SAFETY OUTCOME
D. SECONDARY SAFETY OUTCOMES
Glycemic Control (HbA1c and Target Achievement):
All three included RCTs (n=525) reported mean change in HbA1c from baseline (%). Using a fixed effect model, a statistically significant reduction in HbA1c was observed in the mazdutide group compared with the placebo group (MD -1.53; 95% CI -1.70 to -1.35; p<0.00001; I2=14%) ( Figure 2).
Achievement of the glycemic target of HbA1c <7% was reported by the 3 RCTs (n=521). Participants receiving mazdutide were significantly more likely to achieve the glycemic target than those in the placebo group in the random effects model (OR 9.04; 95% CI 3.05 to 26.76; p<0.0001). Considerable heterogeneity was observed across the studies (I2=76%) ( Figure 3).
Weight reduction efficacy:
Mean change in body weight from baseline (%) was reported by 3 studies (n= 526). Our pooled analysis revealed statistically significant reduction in body weight in the mazdutide group compared with the placebo group in random effect model (MD -4.22; 95% CI -5.71 to -2.73; p<0.00001; I2=59%) ( Figure 4).
Forest plots for the mean change in HbA1c level from baseline (mmol/mol) and body weight (kg) are presented in the extended data in external repository (Fig S1.1and 1.2).
B. Secondary efficacy outcomes:
Fasting Plasma Glucose and Glycemic Variability:
Glycemic control was further assessed using the mean change in fasting plasma glucose level from baseline (mmol/L). Analysis of data from all three RCTs (n=526) revealed a statistically significant reduction in FPG levels in the mazdutide group compared with the placebo group in the random-effects model (MD -2.09; 95% CI -2.74 to -1.45; p<0.00001; I2=66%) ( Figure 5).
Anthropometric Outcomes (Weight loss thresholds, BMI and Waist Circumference):
Weight reduction efficacy was further assessed by the proportion of participants achieving ≥5% and ≥10% weight loss. Both of these outcomes were reported by two RCTs (n=490). Participants receiving mazdutide were significantly more likely to achieve ≥5% reduction in weight than those in the placebo group in the random-effect model (OR 10.61; 95% CI 3.72 to 30.29; p<0.0001; I2=63%) ( Figure 6). Similarly, the odds of achieving ≥10% weight loss were significantly higher in the mazdutide group than in the placebo group in the fixed-effect model (OR 42.56; 95% CI 5.98 to 302.89; p=0.0002; I2=0%) ( Figure 7).
Three studies (n=553) reported mean change in BMI (kg/m2) from baseline and waist circumference (cm) from baseline. A random-effect analysis of data revealed that participants receiving mazdutide showed significant reduction in BMI as compared with the placebo group (MD -1.16; 95% CI -1.54 to -0.78; p<0.00001; I2=60%) ( Figure 8). A significant reduction in waist circumference was also observed in the mazdutide group compared with the placebo group in a fixed-effect model (MD -3.19; 95% CI -3.92 to -2.46; p<0.00001; I2=34%) ( Figure 9).
Cardiometabolic Outcomes (BP, Lipids, Liver Enzymes):
Mean change in systolic and diastolic blood pressure (mmHg) from baseline was reported by all the three included RCTs (n=553). Pooled analysis revealed that mazdutide was associated with significant reduction in both systolic (MD -4.77; 95% CI -6.71 to -2.84; p<0.00001; I2=0%) and diastolic (MD -2.32; 95% CI -3.59 to -1.05; p=0.0004; I2=0%) blood pressure compared with placebo in fixed-effect model ( Figure 10, Figure 11). Three studies (n=553) reported the mean change in triglycerides (mmol/L) from baseline. A statistically significant reduction was observed in mazdutide group compared with the placebo group in a fixed-effect model (MD -0.65; 95% CI -0.82 to -0.47; p<0.00001; I2=23%) ( Figure 12). Additionally, mean change in ALT (U/L) from baseline reported in 3 studies (n= 553) revealed no significant difference between the mazdutide and the placebo groups (MD -1.09; 95% CI -6.91 to 4.73; p=0.71; I2=83%) ( Figure 13).
Forest plots for additional outcomes are reported in extended data in external repository (Fig S1.3 – 1.16).
C. Primary Safety Outcomes:
Treatment emergent adverse effects (TEAEs) were evaluated across all three RCTs (n= 555). Our pooled fixed effect estimate showed that mazdutide was associated with significantly higher odds of TEAEs as compared with placebo (OR 2.20; 95% CI 1.42 to 3.41; p=0.0004; I2=0%) ( Figure 14).
D. Secondary Safety Outcomes:
Severe treatment-emergent adverse effects were reported by two RCTs (n=519). Our analysis revealed no significant difference between the mazdutide and the placebo groups (OR 0.68; 95% CI 0.06 to 7.66; p=0.76) ( Figure 15). Similarly, serious adverse events were evaluated across three RCTs (n=555). Pooled analysis revealed no significant difference between the treatment groups (OR 1.24; 95% CI 0.14 to 10.93; p=0.85; I2=67%) ( Figure 16).
Gastrointestinal Safety outcomes:
Gastrointestinal adverse effects were reported across all three RCTs. Compared with placebo, participants receiving mazdutide had significantly higher odds of diarrhea (OR 4.65; 95% CI 2.68 to 8.08; p<0.00001; I2=0%), nausea (OR 7.43; 95% CI 1.49 to 37.06; p=0.01; I2=58%), vomiting (OR 7.47; 95% CI 2.49 to 22.41; p=0.0003; I2=0%), decreased appetite (OR 8.31; 95% CI 4.05 to 17.05; p<0.00001; I2=0%) and abdominal distention (OR 3.81; 95% CI 1.40 to 10.38; p=0.009; I2=0%) ( Figure 17 to Figure 21).
Cardiac safety outcomes:
Cardiac adverse effects were assessed across the included studies. For the composite outcome of any cardiac disorder, no significant difference was found between the mazdutide and the placebo groups (OR 1.71; 95% CI 0.55 to 5.29; p=0.35; I2=0%) ( Figure 22). Similarly, no significant difference was observed between the treatment groups for sinus tachycardia (OR 1.17; 95% CI 0.27 to 5.15; p=0.83; I2=0%) and first-degree AV block (OR 1.82; 95% CI 0.20 to 16.65; p=0.60; I2=0%) ( Figure 23, Figure 24).
All primary and secondary efficacy outcomes, together with their pooled effect estimates and statistical analyses, are summarized in Table 3. Additional safety outcomes are presented in the extended data in external repository (Fig S 1.17 – 1.28)
Glycemic outcomes:
Subgroup analyses based on mazdutide dose were conducted for the mean change in HbA1c (%) from baseline and participants achieving HbA1c <7%. No significant subgroup differences were identified for either outcome.
Subgroup analysis by treatment duration demonstrated a significant reduction in HbA1c (%) from baseline (MD −1.56; 95% CI −1.73 to −1.38; p<0.00001; I2=0%) and significantly higher odds of achieving HbA1c <7% (OR 14.04; 95% CI 5.52 to 35.70; p<0.00001; I2=68%) (Fig S5.1, Fig S5.2). Findings were consistent with the primary pooled analysis.
Weight and metabolic outcomes:
Although the combined analysis of body weight change % favored mazdutide, the 3 mg dose subgroup did not reach statistical significance (MD −1.56; 95% CI −4.38 to 1.27; p=0.28; I2=59%) (Fig S2.6). Likewise, despite significant reductions in BMI and waist circumference in the overall pooled analyses, the 3 mg dose subgroup demonstrated no significant reductions in BMI (MD −0.43; 95% CI −1.00 to 0.14; p=0.14; I2=64%) or waist circumference (MD −0.65; 95% CI −3.31 to 2.01; p=0.63; I2=61%) (Fig S 2.7, Fig S2.8).
Cardio metabolic outcomes:
In contrast to the combined analysis, which showed no significant difference in mean change in ALT (U/L) between the treatment groups, dose specific subgroup analysis revealed significant reductions in ALT levels with Mazdutide 4/4.5mg (MD −7.08; 95% CI −10.01 to −4.14; p<0.00001; I2=0%) (Fig S3.22) and 6mg (MD −7.04; 95% CI −9.97 to −4.10; p<0.00001; I2=35%) (Fig S4.22) compared with placebo.
Safety dose- response:
Subgroup analyses based on mazdutide dose demonstrated findings consistent with the overall pooled analysis. No significant subgroup differences were observed across the evaluated safety outcomes.
Treatment duration-dependent safety outcomes:
Subgroup analyses based on treatment duration (≥20 weeks) were conducted for all pre-specified safety outcomes. No significant subgroup differences were identified for any outcome.
See supplemental file Figure S2.1-S2.26, figure S3.1-S3.49, Figure S4.1-S4.49, and Figure S5.1-S5.42
Sensitivity analysis was performed using a leave-one-out approach to explore sources of heterogeneity, as substantial heterogeneity (I2 >75%) was observed across multiple outcomes. Zhu et al. was identified as the primary contributor to heterogeneity. Following exclusion of this study, heterogeneity was reduced for achievement of HbA1c <7% (I2: 76% to 54%), change in HOMA2-B from baseline (I2: 86% to 0%), change in ALT from baseline (I2: 83% to 0%), and change in AST from baseline (I2: 77% to 0%). While the results for achievement of HbA1c <7% (p<0.00001) and HOMA2-B (p=0.0003) remained statistically significant, mean change in ALT (p=0.01) and AST (p=0.03) changed from non-significant to statistically significant following removal of Zhu et al. Detailed results of the sensitivity analysis are presented in Table 4. Forest plots for sensitivity analyses are provided in the extended data in external repository (Fig S6.1 – Fig S6.8).
The methodological quality of the included randomized controlled trials was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool. All three included RCTs were judged to be at low risk of bias across all five assessed domains, including bias arising from the randomization process, deviations from intended interventions, missing outcome data, measurement of outcomes, and selection of the reported results. Consequently, each study received an overall judgment of low risk of bias. The traffic-light plot and summary plot illustrating the domain-specific and overall risk-of-bias assessments are presented in Figure 25 and Figure 26, respectively.
The certainty of evidence for the evaluated efficacy and safety outcomes was assessed using the GRADE framework and is summarized in the Summary of Findings table ( Table 1 in extended data in external repository). High-certainty evidence supported the effects of mazdutide on HbA1c reduction, treatment-emergent adverse events, and diarrhea. Moderate-certainty evidence was observed for body weight reduction, hypoglycemia, and vomiting. In contrast, the certainty of evidence was low for HbA1c target achievement (<7.0%) and ≥5% weight loss, whereas serious adverse events and nausea were supported by very low-certainty evidence. Overall, the certainty of evidence ranged from very low to high, reflecting high confidence for several key efficacy and safety outcomes while indicating greater uncertainty for outcomes downgraded because of study limitations identified through the GRADE assessment ( Table 2 in extended data in external repository).
In this systematic review and meta-analysis of three randomized controlled trials involving 613 participants with type 2 diabetes mellitus (T2DM), mazdutide demonstrated significant improvements across multiple glycemic, anthropometric, and cardiometabolic outcomes. Compared with placebo, mazdutide significantly reduced HbA1c, fasting plasma glucose, body weight, BMI, waist circumference, blood pressure, and triglyceride levels, while substantially increasing the likelihood of achieving HbA1c <7% and clinically meaningful weight-loss thresholds. Although treatment-emergent adverse events were more common among participants receiving mazdutide, no significant increase in severe treatment-emergent adverse events or serious adverse events was observed. Gastrointestinal adverse events represented the predominant safety signals. Collectively, these findings suggest that mazdutide provides clinically meaningful metabolic benefits with an acceptable short-term safety profile in individuals with T2DM.
The GRADE assessment demonstrated that the certainty of evidence ranged from very low to high across the evaluated outcomes. High-certainty evidence supported the beneficial effects of mazdutide on HbA1c reduction, as well as the increased incidence of treatment-emergent adverse events and diarrhea. Moderate-certainty evidence supported body weight reduction, hypoglycemia, and vomiting. In contrast, evidence for HbA1c target achievement and ≥5% weight loss was rated as low certainty, while serious adverse events and nausea were supported by very low-certainty evidence because of concerns related to inconsistency and/or imprecision. These findings indicate that the overall evidence supporting mazdutide is robust for several clinically important outcomes, although additional adequately powered randomized controlled trials with longer follow-up are warranted to strengthen the evidence for outcomes with lower certainty.
The marked improvement in glycemic control observed in our analysis represents one of the most clinically relevant findings of this study. We found that mazdutide significantly reduced HbA1c and fasting plasma glucose levels while markedly increasing the likelihood of achieving the recommended glycemic target of HbA1c <7%.19 These findings are consistent with the pharmacological profile of mazdutide as a dual GLP-1 and glucagon receptor agonist, which improves glucose homeostasis through enhanced glucose-dependent insulin secretion, suppression of inappropriate glucagon release, and delayed gastric emptying.7,20 Importantly, the magnitude of HbA1c reduction observed in the present analysis is consistent with the substantial glycemic improvements reported with the newer incretin- based therapies and highlights the potential of mazdutide as an effective therapeutic option for patients with inadequately controlled T2DM.21
Beyond glycemic control, mazdutide demonstrated substantial benefits across multiple measures of adiposity. Participants receiving mazdutide experienced significant reductions in body weight, BMI, and waist circumference and were considerably more likely to achieve both ≥5% and ≥10% weight-loss targets than those receiving placebo. These findings are particularly important given the close relationship between obesity and T2DM, where excess adiposity contributes to insulin resistance, chronic inflammation, and increased cardiometabolic risk.22,23 The observed weight-loss effects likely reflect the complementary actions of dual receptor agonism, whereby GLP-1 receptor activation reduces caloric intake through appetite suppression and delayed gastric emptying, while glucagon receptor activation may enhance energy expenditure and lipid utilization.24,25 Interestingly, subgroup analyses suggested that the lowest evaluated dose (3 mg) did not consistently achieve significant reductions in body weight, BMI, or waist circumference, raising the possibility of a dose-response relationship. Although these findings should be interpreted cautiously because of limited sample sizes, they may provide useful insights for future dose optimization strategies.
An important observation of this meta-analysis is that the benefits of mazdutide extended beyond glucose lowering and weight reduction. Compared with placebo, mazdutide significantly improved several cardiometabolic risk factors, including systolic blood pressure, diastolic blood pressure, triglyceride levels, and measures of central adiposity. Such findings are clinically relevant because cardiovascular disease remains the leading cause of morbidity and mortality among individuals with T2DM.26 The cardiometabolic benefits observed in our analysis may be explained by the mechanisms proposed for dual GLP-1/glucagon receptor agonists, including appetite suppression, increased energy expenditure, lipid oxidation, and hepatic lipid turnover, while also improving endothelial function and reducing inflammation, collectively contributing to improvements in adiposity and cardiovascular risk factors beyond glycemic control alone.27 We also observed significant reductions in triglyceride levels, a finding of particular importance given the established association between hypertriglyceridemia, insulin resistance, and residual cardiovascular risk.28 Although the pooled analysis did not demonstrate a statistically significant reduction in ALT levels, sensitivity analyses revealed significant improvements following exclusion of the study contributing most substantially to heterogeneity. While these findings suggest a potential beneficial effect on hepatic metabolism, the available evidence remains insufficient to draw definitive conclusions regarding liver-related outcomes.
The broad metabolic effects observed with mazdutide likely reflect its unique dual GLP-1/glucagon receptor agonist mechanism. While GLP-1 receptor activation improves glycemic control and suppresses appetite, glucagon receptor agonism may increase energy expenditure, promote lipid oxidation, and enhance hepatic lipid turnover, potentially contributing to the substantial reductions in body weight and adiposity observed across the included trials.27 These mechanistic features may provide complementary metabolic effects beyond those achieved with GLP-1 receptor activation alone, potentially contributing to the broad cardiometabolic benefits observed with mazdutide. Although the observed reductions in blood pressure, triglycerides, and central adiposity are encouraging, dedicated cardiovascular outcome trials will be required to determine whether these improvements ultimately translate into reductions in cardiovascular morbidity and mortality.
Subgroup analyses provided additional insight into treatment response. While improvements in glycemic outcomes were observed across dose categories, the lowest evaluated dose (3 mg) did not consistently achieve statistically significant reductions in body weight, BMI, or waist circumference. These findings suggest a potential dose-response relationship, whereby higher doses may be required to maximize weight-related benefits. Furthermore, treatment-duration subgroup analyses demonstrated sustained improvements in glycemic outcomes among studies with follow-up durations of ≥20 weeks, supporting the durability of the observed metabolic effects over the short-to-intermediate term.
Several efficacy outcomes demonstrated moderate-to-substantial heterogeneity. Potential explanations include differences in treatment duration, dose escalation schedules, baseline metabolic characteristics, and study size across the included trials. Sensitivity analyses identified the DREAMS-1 trial as a major contributor to heterogeneity for several outcomes. Nevertheless, the direction of effect remained consistent across studies, supporting the robustness of the observed glycemic and weight-loss benefits.
The safety profile observed in this analysis was generally consistent with that reported for other incretin-based therapies.29 While mazdutide was associated with a higher incidence of treatment-emergent adverse events, no significant increase in severe treatment-emergent adverse events or serious adverse events was identified. Gastrointestinal adverse events, including nausea, vomiting, diarrhea, decreased appetite, and abdominal distention, were significantly more frequent among participants receiving mazdutide. These effects are biologically plausible and consistent with the known mechanisms of GLP-1 receptor agonism, particularly delayed gastric emptying and central appetite regulation.30 Importantly, gastrointestinal adverse events associated with incretin-based therapies are often transient and tend to improve with continued treatment or gradual dose escalation.29 Reassuringly, no significant differences were observed in cardiac adverse events, including sinus tachycardia and first-degree atrioventricular block, although the included studies were not designed to evaluate major cardiovascular outcomes. Consequently, larger studies with longer follow-up are required to establish the long-term cardiovascular safety of mazdutide.
Subgroup analyses generally supported the robustness of the primary findings across different treatment durations and dose regimens. Glycemic improvements remained consistent irrespective of subgroup, whereas anthropometric outcomes showed a trend toward greater efficacy with higher maintenance doses, with the 3 mg regimen not consistently achieving statistically significant reductions in body weight, BMI, or waist circumference. Similar dose-dependent improvements in weight loss have been reported in phase 2 clinical trials of mazdutide, suggesting that adequate dose escalation may be necessary to achieve maximal therapeutic benefit. These findings are also consistent with the exposure–response relationship described for incretin-based therapies, whereby higher maintenance doses are associated with greater metabolic efficacy.31 Subgroup analyses of safety outcomes were consistent with the primary findings, with no evidence of clinically meaningful differences across dose or treatment-duration subgroups. Nevertheless, these subgroup findings should be interpreted cautiously because of the limited number of available studies and their exploratory nature.
This study is the first systematic review and meta-analysis specifically evaluating mazdutide in individuals with T2DM. Our findings are consistent with the previous meta-analysis by Nalisa et al., which reported significant improvements in body weight, blood pressure, lipid parameters, and glycemic outcomes, together with a safety profile predominantly characterised by mild to moderate gastrointestinal adverse events.32 However, unlike the previous analysis, which included both diabetic and non-diabetic populations and primarily focused on weight-loss efficacy, the present study exclusively focussed on individuals with T2DM and provides a more comprehensive assessment of glycemic, cardiometabolic parameter, subgroup analyses, and safety outcomes. Our findings are also consistent with a recent meta-analysis of randomized controlled trials conducted in overweight and obese adults without diabetes, which demonstrated significant reductions in body weight, waist circumference, systolic blood pressure, total cholesterol, and LDL cholesterol, together with a safety profile characterized predominantly by mild-to-moderate gastrointestinal adverse events. These observations suggest that the favorable effects of mazdutide on weight reduction and cardiometabolic risk factors extend beyond diabetic populations.13
The ability of mazdutide to simultaneously improve glycemic control, promote weight loss, and favorably influence cardiometabolic risk factors aligns with contemporary treatment paradigms that increasingly emphasize comprehensive metabolic risk reduction rather than glucose lowering alone.33 Given the high prevalence of obesity among individuals with T2DM, therapies capable of addressing both hyperglycemia and excess adiposity may offer substantial clinical value.34 The growing evidence base for mazdutide, including recent phase 3 data demonstrating sustained and clinically meaningful weight reduction, further supports its potential role as a next-generation incretin-based therapy capable of addressing multiple components of cardiometabolic disease.35
The efficacy profile observed in this analysis appears broadly consistent with that reported for other multi-receptor incretin therapies. For example, tirzepatide has demonstrated substantial reductions in HbA1c and body weight while maintaining a safety profile characterized predominantly by gastrointestinal adverse events.21 Although direct cross-trial comparisons should be interpreted cautiously because of differences in study populations and trial designs, the overall direction of benefit observed with mazdutide supports the emerging role of multi-receptor agonist therapies as an important therapeutic strategy in the management of T2DM.
Several strengths of this study should be acknowledged. First, this represents the first quantitative synthesis focused exclusively on mazdutide in patients with T2DM. Second, only randomized controlled trials were included, providing evidence derived from the highest level of clinical study design currently available for this intervention. Third, a broad range of clinically relevant efficacy and safety outcomes were evaluated, allowing a comprehensive assessment of the therapeutic profile of mazdutide. Finally, subgroup and sensitivity analyses were performed to explore heterogeneity and assess the robustness of pooled estimates, while the use of GRADE methodology enhances the interpretability and clinical applicability of the findings.
Nevertheless, several limitations should be considered. Only three randomized controlled trials met the eligibility criteria, resulting in a relatively modest sample size and limiting the precision of certain estimates, particularly for uncommon adverse events. The duration of follow-up ranged from 12 to 24 weeks, with only one study incorporating a longer extension phase; therefore, the long-term durability of treatment effects and safety profile remain uncertain. In addition, all included studies were conducted in Chinese populations, which may limit the generalizability of these findings to other ethnic groups and healthcare settings. Variations in treatment duration and dose regimens may also have contributed to heterogeneity across several outcomes. Furthermore, the included studies were not designed to evaluate major adverse cardiovascular events, cardiovascular mortality, or long-term hepatic outcomes, precluding definitive conclusions regarding these clinically important endpoints. Finally, assessment of publication bias was limited by the small number of available studies. Although several clinically important outcomes were supported by moderate- to high-certainty evidence, the certainty for some efficacy and safety outcomes was downgraded because of heterogeneity, imprecision, and the limited number of available randomized controlled trials.
In conclusion, the current evidence suggests that mazdutide is an effective therapeutic option for individuals with T2DM, producing significant improvements in glycemic control, body weight, and multiple cardiometabolic risk factors while maintaining a generally manageable short-term safety profile characyerized by gastrointestinal adverse events. Larger multicenter trials with longer follow-up durations and more diverse populations are needed to confirm these findings and further define the long-term efficacy, safety, and cardiovascular impact of mazdutide.
Ethical approval was not required for this study, as it is based on data extracted from previously published literature.
Not applicable.
This systematic review and meta-analysis was registered in the PROSPERO database CRD420261422849.
Not applicable. This study is a systematic review and meta-analysis of previously published studies and does not involve direct participation of human subjects. All included studies had obtained appropriate ethical approval and informed consent from participants.
During manuscript preparation, the authors utilized AI-assisted tools (e.g., ChatGPT and DeepSeek) for language editing and structural refinement. The authors take full responsibility for the accuracy, integrity, and originality of the final content.
The corresponding author affirms that this manuscript represents an honest, accurate, and transparent account of the study being reported; that no important aspects have been omitted; and that any discrepancies from the planned study have been clearly explained.
Zenodo: Efficacy and Safety of Mazdutide for Type 2 Diabetes: Underlying Data. DOI:
https://doi.org/10.5281/zenodo.2164980836
This repository contains the following underlying data:
• Mazdutide vs Placebo.xlsx: Study-level extracted data used for all quantitative analyses included in this systematic review and meta-analysis.
• PRISMA_ 2020_ checklist nova 22.png: Completed PRISMA 2020 checklist.
• PRISMA flow diagram Nova 22.png: PRISMA 2020 flow diagram illustrating study selection.
• Extended data file NOVA 22.docx
Extended data file named Extended data file NOVA 22.docx contains complete electronic search strategies; Supplementary Table 1 (GRADE Summary of Findings); Supplementary Table 2 (GRADE Evidence Profile); Supplementary Figures S1.1–S1.28 (combined analyses of additional efficacy outcomes); Supplementary Figures S2.1–S2.26 (subgroup analyses of 3 mg mazdutide versus placebo); Supplementary Figures S3.1–S3.49 (subgroup analyses of 4/4.5 mg mazdutide versus placebo); Supplementary Figures S4.1–S4.49 (subgroup analyses of 6 mg mazdutide versus placebo); Supplementary Figures S5.1–S5.42 (subgroup analyses by treatment duration); and Supplementary Figures S6.1–S6.8 (leave-one-out sensitivity analyses).
Data are available under the terms of the licence applied to the Zenodo record.