Metformin: Anchoring Potential in GLP-1 RA Care Journey

India is confronting a metabolic health crisis of significant magnitude, 254 million adults with generalised obesity, 351 million with abdominal obesity^[1], nearly 90 million living with diabetes^[2], and a metabolic syndrome burden of 44.6% across urban and rural populations.^[3] However, in a promising transition for all metabolic health stakeholders, the treatment landscape is likely to drastically shift with generic GLP-1 receptor agonists (GLP-RAs) becoming available in India for the first time, marking a meaningful change in access for a class that was, until recently, out of reach for most patients. Interestingly, metformin continues to hold its ground in this evolving therapeutic landscape towards wider access to GLP-RAs, as a potential anchor of the GLP-1 RA care journey.^[4]

Metformin with GLP-1 RA: Early Promising Evidence Presented at EASD Conference

The evidence supporting the use of metformin in the GLP-1 RA care continuum is gaining momentum. Data presented at the 61st Annual Meeting of the European Association for the Study of Diabetes (EASD) 2025, a few months back, have provided new insights into the potential role of metformin within a GLP-1 RA-based regimen continuum, with findings that extend beyond glycaemic outcomes into territory that carries greater clinical weight. These are early signals, but ones that deserve careful attention and have clinical implications for how combination therapy of metformin and GLP-RA is approached in routine practice.^[5]

Metformin with GLP-1 RA: Rationale for Consideration in Obese T2D Patients

The rationale for combining metformin with a GLP-1 receptor agonist lies in their complementary mechanisms across metabolic tissues. Metformin suppresses hepatic gluconeogenesis via AMPK activation,^[6] while GLP-1 receptor agonists enhance glucose-dependent insulin secretion and promote satiety, improving both fasting and postprandial glycaemic control.^[7] Both metformin and GLP-1RAs are known to improve leptin sensitivity, making the brain more responsive to the anorexigenic effects of the adipokine.^[8] Together, they provide synergistic efficacy with potential benefits on weight reduction.

Metformin Use with GLP-1 RA: Synergy Towards Better Outcomes

Metformin with GLP-RA – Effect on Weight-Lowering Response: A 52-week prospective study including 194 obese T2D patients showed concomitant initiation of metformin alongside GLP-1 receptor agonist therapy is associated with enhanced weight loss efficacy, suggesting a potential synergistic metabolic interaction that improves the likelihood of achieving clinically meaningful weight reduction.^[8]

Metformin with GLP-RA & Long-term Outcomes: In patients with T2D, dual therapy with metformin and GLP-RA has demonstrated a 39% lower incidence of adiposity-related cancers (HR 0.61) and a 67% reduction in all-cause mortality (HR 0.33) compared to DPP-4 inhibitor use, with effects most pronounced in younger people with obesity.^[9]

Metformin Use Post-GLP-1 RA: Weight Maintenance Effect

The post-GLP-1 RA period represents a significant clinical vulnerability. Discontinuation rates range from 37% to 81% within the first year, driven by cost, side effects, and access barriers, with weight regain thereafter mediated through hormonal dysregulation, CNS maladaptation to reduced GLP-1 signaling, and β-cell dysfunction. In this context, metformin emerges as the most pragmatic maintenance strategy.^[10,11] In a real-world cohort transitioning off GLP-1 RA therapy to cost-effective medications with weight-lowering effects, metformin was the most frequently utilized agent as maintenance treatment in about 80% patients. Patients achieved substantial weight loss during the initial GLP-1 RA phase (~18–22% at 12 months), which was subsequently maintained after its discontinuation, with total weight reduction reaching 25.5% (95% CI 23.1–27.9%) at 593 days, with most patients on metformin. These findings indicate that metformin could help sustain weight loss achieved with GLP-1 RAs, supporting their role in long-term weight maintenance across the treatment continuum.^[12]

Metformin: Anchor in the GLP-1 RA Care Continuum Journey

The mechanistic, real-world, clinical trials and pharmacovigilance evidence landscape suggests metformin as the potential anchor pharmacological agent across the entire GLP-1 RA care continuum, during therapy and beyond.Table 1 summarises the key potential outcome benefits at each phase.

Table 1. Metformin- Anchoring Benefits with and Post GLP-1 RA Therapy

Metformin with GLP-RA -Safety Edge:

A pooled analysis across four major cardiovascular outcome trials (n=16,996; LEADER, STEP 2, SUSTAIN-6, PIONEER 6) showed that metformin use did not increase the incidence or severity of gastrointestinal adverse events or drive treatment discontinuation; notably, metformin non-users experienced numerically higher gastrointestinal event rates.^[13] These findings are further reinforced by pharmacovigilance data from the FDA Adverse Event Reporting System (FAERS) database (n=48,214 reports), where GLP-1RA-related gastrointestinal adverse events, including nausea (9651 vs 38,030) and vomiting (4383 vs 17,062), were lower with combination therapy compared to GLP-1RA monotherapy, suggesting improved tolerability when metformin is added.^[14]

Together, these data support the continued use of metformin across the GLP-1 RA care journey without additional safety compromise.^[9]

Key Takeaways

✔ With rising GLP-1 RA access in India’s metabolic crisis revolutionizing treatment paradigm in the real world, metformin remains the anchor of the gluco-metabolic care journey.

✔ The combination of metformin and GLP-1 RAs, via complementary mechanisms and improved leptin sensitivity, translates into greater weight loss success response and reduced GLP-1RA-related adverse events, particularly with concurrent initiation of both agents.

✔ Research indicates concomitant metformin emerges as a pragmatic maintenance strategy in the post–GLP-1 RA period, used in 80% of patients following discontinuation.

✔ The evidence consistently indicates the potential of metformin as the anchor pharmacological agent drug across the entire GLP-1 RA care continuum, during therapy and beyond, when clinically indicated.

Abbreviations: GLP-1 RA = glucagon-like peptide-1 receptor agonist; EASD = European Association for the Study of Diabetes; AMPK = adenosine monophosphate-activated protein kinase; FAERS = FDA Adverse Event Reporting System; GI = gastrointestinal; OR = odds ratio; CI = confidence interval; HR = hazard ratio; ROR = reporting odds ratio; DPP-4i = dipeptidyl peptidase-4 inhibitor; CNS = central nervous system; BMI = body mass index.