Why are grams of metformin recommended to lower hyperglycaemia in type 2 diabetic patients whereas the dose ranges from micrograms to milligrams for all other antidiabetic agents? Why is that 50% of the patients should discontinue or reduce the daily therapeutic doses to avoid diarrhoea? Why has the previously established mode of action of metformin been continuously disputed and re-evaluated by the scientific community? To these questions, Shin et al 1 shifted again the paradigm related to numerous modes of action of metformin described so far to show that the drug lowers glycaemia by targeting gut microbiota. The gutsy role of metformin might have been uncovered.

For the last 50 years, ever since the biosynthesis of metformin by Emil Werner and James Bell in 1922, the scientific community has been revisiting the mode of action of the …