Methimazole USP For Compounding (API)Methimazole USP is an active pharmaceutical ingredient (API) used in the production of medications to treat hyperthyroidism, also known as an overactive thyroid. It works by inhibiting the production of thyroid hormones in the body, helping to reduce symptoms such as rapid heartbeat, weight loss, and nervousness. It is classified as an antithyroid medication and is available in various dosage forms, including tablets, ointments, and injections.