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Mfn4.0
Metformin Research
Too few graded studies
2,687 peer-reviewed studies
Showing the 1004 most recent of 2687 studies.
All 2683 database studies by type: RCT 1968 · Meta-Analysis 577 · Systematic Review 117 · Review 14 · other 4 · Observational 3
What the evidence says
Too few graded studies
Metformin doesn't have enough studies with structured effect-size data yet to pool a verdict. Browse the studies below for individual findings.
Most evidence is from high-quality meta-analyses and randomised trials published 1998–2026 with a typical study size of 753 participants.
Based on 1,002 studies · 350 meta-analyses · 557 RCTs · 753 total participants
Confidence
High confidence
By outcome
Glycemic & metabolicLowers blood glucose and HbA1c and improves insulin sensitivity — the established, proven effect · Weeks · Improves insulin sensitivity; the established first-line metabolic effect (longevity/geroprotection remains contested) · Weeks
Too few graded studies341 studies
Exercise interference
Too few graded studies27 studies
Safety profile
Too few graded studies26 studies
Aging & mortalityObservational/meta-analytic data suggest lower all-cause mortality and age-related disease in diabetics — confounded, not proven causal · Years
Too few graded studies20 studies
Active research area
812 studies in the last 5 years · Latest meta-analysis: 2026
199820122026
1Meta-Analysis2026
In plain English: In this IPD meta-analysis, metformin was not associated with a reduction in GDM, but was associated with an increase in gestational age at delivery.
Mousa A, Løvvik TS, Carlsen SM, Belsti Y, Enticott J, Tay CT, Nikkinen H, Morin-Papunen L, Tertti K, Rönnemaa T, Rowan J, Dodd J, Deussen A, Hague WM, Zawiejska A, Arshad R, Mathews JE, Wasim T, Mohamed MA, Mohebbi M, Yefet E, Nachum Z, Ainuddin J, Refuerzo JS, Burden C, Norman JE, Syngelaki A, Nicolaides K, Shehata H, Vanky E, Teede HJ. · NEJM evidence (2026)
Results Ten trials (N=2695) met inclusion criteria and seven provided IPD (n=2485; 92.2% of available IPD).
Metformin was associated with marginally lower fasting blood glucose level (mean difference [MD], -0.06 mmol/l; 95% CI, -0.10 to -0.01), with no apparent difference in 2-hour postload blood glucose level.
Metformin was also associated with longer gestation (MD, 0.30 weeks' gestation; 95% CI, 0.06 to 0.54), lower odds of preterm birth (adjusted odds ratio, 0.64; 95% CI, 0.47 to 0.89), and larger neonatal head circumference (MD, 2.43 percentile; 95% CI, 0.13 to 4.72).