Metformin's efficacy data for obesity treatment in youth is described as what?

• A. Clear and consistent
• B. Mixed efficacy data
• C. Not tested
• D. Extremely effective

Answer: (B)

Metformin’s effect on obesity in youth is described as mixed because studies show inconsistent results. Some trials report small reductions in BMI or BMI z-score, particularly in subgroups with insulin resistance (like adolescents with PCOS), while other studies find little to no weight change. Variability in study design—duration, dosage, adherence, participant characteristics (age, pubertal stage, presence of insulin resistance or PCOS), and how weight outcomes are measured—leads to this lack of a uniform effect. Because the data don’t point to a clearly positive or consistently absent effect across all youth with obesity, the overall label is mixed efficacy.