Weight, insulin and blood sugar landed the same on either one
Eight randomised trials, 1,088 women: body mass index, fasting insulin, fasting blood sugar, insulin resistance and a ratio between two pituitary hormones all crossed zero.
What the study found
Against metformin, all five pooled markers came out level
Eight randomised trials, 1088 women: body mass index, fasting insulin, fasting blood sugar, insulin resistance and the ratio between two pituitary hormones all crossed zero. The guideline still puts metformin first for hirsutism and central weight gain, which this pooling never measured.
The caveat · Too few trials to prove a tie
A null result is not proof of equivalence. Eight small trials, with moderate inconsistency on three of the five outcomes, are underpowered to rule out a real difference between the two. No risk-of-bias assessment or certainty grading is reported.