Metformin modulates metabolism in multiple cell types and is currently used to reduce glucose levels and insulin resistance in diabetic patients. Bae et al. reported that the use of metformin correlated with a lower risk of developing vitiligo, suggesting that metformin could potentially mitigate the disease. The investigators found that treating mouse T cells with metformin during activation reduced their mitochondrial respiration and proliferation, while mice treated with metformin reversed their vitiligo. Therefore, the investigators hypothesize that regulation of CD8+ T cell metabolism in vitiligo patients by metformin will reduce their proliferation and cytotoxic activity, resulting in skin repigmentation and thus serve as a novel treatment.~The investigators plan to treat approximately 30 subjects with stable vitiligo.~Metformin is FDA-approved for use with dosing from 500-2000 mg/day. It has a rare risk of lactic acidosis, which can be meaningful in patients with risk factors such as renal insufficiency. This risk is directly proportional to the dose given; therefore, participants will be started at a lower dose (500 mg twice daily) with follow-up to monitor any arising symptoms. Per current clinical recommendations, participants will only be increased to higher-dose metformin (1000 mg twice daily) if the initial dose is tolerated.
Metformin modulates metabolism in multiple cell types and is currently used to reduce glucose levels and insulin resistance in diabetic patients. The investigators hypothesize that oral metformin can regulate the metabolism of CD8+ T cells, reduce their cytotoxic activity and thus serve as a novel treatment for vitiligo.