T4 is the main hormone produced by the thyroid glands, with a smaller amount of T3 being produced. T3 is the active form of thyroid hormone found in the body and a majority of it is made through conversion of T4. Patients with hypothyroidism are often first prescribed capsules with T4 only. If the patient is still able to convert T4 hormone to T3, this is an effective treatment. In some individuals, the conversion process is not as efficient and T3 levels remain low even after supplementation with T4. Patients with the inability to convert T4 to T3 may be offered treatment with liothyronine, a synthetic version of the endogenously produced T3 hormone.

Liothyronine Sustained-Release Capsules

Many doctors recommend taking T3 in sustained release form because T3 has a short half-life. The commercially available T3 sold under the brand name Cytomel is not sustained release. All of the liothyronine capsules we compound are made as sustained release capsules.