Thiazolidinediones (TZDs) are a class of medications used to treat type 2 diabetes. They work by improving the body's sensitivity to insulin, which helps lower blood sugar levels. TZDs target fat cells, muscle, and the liver to enhance glucose uptake and reduce insulin resistance. Common examples of TZDs include pioglitazone and rosiglitazone. These medications are typically prescribed when other diabetes treatments are not sufficient. While effective, TZDs may have side effects, such as weight gain and an increased risk of heart problems, so they are used with caution in certain patients.