In this analysis, from age and sex‐matched youth with T1D treated with metformin or placebo for 6 months, we demonstrate for the first time that metformin has an increase on the PRGP2 (peptidoglycan recognition protein 2 also known as N‐acetylmuramoyl‐L‐alanine amidase) and A2MG (Alpha‐2‐macroglobulin) proteins on HDL. The gene discussed is PRRG2; the disease is type 1 diabetes mellitus.