Overview

• A Kobe University cross-sectional study of 189 adults with type 2 diabetes found significantly reduced serum copper and iron and increased zinc in metformin users compared with non-users.
• The associations persisted after adjustments for age, sex, body mass index, kidney function and concomitant medications, with metformin use emerging as an independent predictor.
• Participants taking metformin also had lower vitamin B12 and higher homocysteine, reinforcing an established safety concern that may warrant monitoring.
• Published in BMJ Open Diabetes Research & Care, the findings align with laboratory evidence that metformin binds transition metals, though they do not establish causality.
• Investigators highlight imeglimin as a comparator that likely lacks metal-binding properties and report comparative and animal studies in progress, noting cobalt results were constrained by assay sensitivity.