Levothyroxine Sodium

What is Levothyroxine Sodium?

Levothyroxine sodium is a synthetic bioidentical form of T4, the thyroid hormone that the body converts into T3, its active form. Once converted, these hormones bind to thyroid receptors and influence DNA transcription and protein synthesis, supporting normal metabolism, growth, and development.

Levothyroxine may affect how genes are expressed and how proteins are made, which would raise the body’s basal metabolic rate, supporting normal growth and development, and helping drive processes like making glucose and releasing stored glycogen. Levothyroxine is commonly used as the primary option for hormone replacement in congenital or acquired hypothyroidism, including primary, secondary, and tertiary (central) forms, because it provides a stable source of T4 that the body can regulate naturally through conversion to T3.