The Health Influences of Puberty (HIP) Study

After randomization, the study drug (metformin or placebo) is gradually titrated to full dose of 1000 mg BID (or to maximum tolerated, at least 500 mg BID) over a period of 4 weeks to minimize adverse gastrointestinal effects. Participants are seen every three months to measure compliance and dispense new study drug. Every 6 months, they also have a physical examination in order to determine puberty staging. Study measurements (IVGTT, bloodwork, DXA) are performed at Tanner 4 puberty and Tanner 5 (puberty completion), at which time the study drug is stopped. Study measurements will be performed again 6 months after study drug is completed to assess if effects are persistent after study drug is stopped. During the treatment period, all participants receive standard lifestyle counseling.

Stamped placebo pill to look like the 1000 mg metformin pill Dosage: 1 pill taken orally twice daily Duration: From early puberty (Tanner 3-4) until puberty completion (Tanner 5), approximately 3 years