Current options to treat insulin resistance in diabetes are fairly limited. For this reason, novel treatments would represent a major progress. The generic drug hydroxychloroquine (HCQ) has poorly understood effects on blood sugar metabolism. In this study, the investigators will examine the mechanisms by which this drug affects glucose metabolism and which cells are affected. Findings emanating from this project will help establish whether HCQ may be a viable treatment for disorders of glucose metabolism.

Inclusion Criteria:

• Age 21-69 years-old;
• BMI 28-40;
• Presence of at least one of the following markers of insulin resistance: a) fasting hyperinsulinemia (>7 uU/ml by ultrasensitive insulin assay); impaired fasting glucose (100-125 mg/dl); prior history of impaired glucose tolerance provided by the participant; history of previous gestational diabetes; history of PCOS; waist circumference >40" (men) or >35" (women) (cut-offs from ATP-III criteria for metabolic syndrome).

Exclusion Criteria:

• Pregnancy, or unable/unwilling to avoid pregnancy during the study;
• Unstable cardiopulmonary disease, hepatitis, liver dysfunction, renal insufficiency, or any other medical condition affecting glucose metabolism or safety during the study;
• Diabetes;
• Medications that affect glucose metabolism: (e.g. systemic glucocorticoids, antipsychotics);
• History of hypersensitivity to local lidocaine, similar anesthetics, or HCQ;
• History of G6PDH deficiency;
• History of retinopathy;
• Weight instability (>3Kg of weight change in the past three months);
• Bariatric surgery in the last two years, intention to lose weight or engage in exercise regimen during study;
• Alcohol intake >1 drink/day (averaged);
• Hemoglobin <10g%