Both T3 and T4 are used to treat<unk> deficiency (hypothyroidism).<unk> ey are both absorbed well by<unk> e stomach, so can be given orally. Levothyroxine is<unk> e pharmaceutical name of<unk> e manufactured version of T4, which is metabolised more slowly<unk> an T3 and hence usually only needs once-daily administration. Natural desiccated<unk>  are derived from pig<unk> yroid glands, and are a "natural" hypothyroid treatment containing 20% T3 and traces of T2, T1 and calcitonin. Also available are synthetic combinations of T3/T4 in different ratios (such as liotrix) and pure-T3 medications (INN: liothyronine). Levothyroxine Sodium is usually<unk> e first course of treatment tried. Some patients feel<unk> ey do better on desiccated<unk> ; however,<unk> is is based on anecdotal evidence and clinical trials have not shown any benefit over<unk> e biosynthetic forms.<unk> yroid tablets are reported to have different effects, which can be attributed to<unk> e difference in torsional angles surrounding<unk> e reactive site of<unk> e molecule.<unk> yronamines have no medical usages yet,<unk> ough<unk> eir use has been proposed for controlled induction of hypothermia, which causes<unk> e brain to enter a protective cycle, useful in preventing damage during ischemic shock. Synthetic<unk> yroxine was first successfully produced by Charles Robert Harington and George Barger in 1926. Formulations Structure of (S)-thyroxine (T4). (S)-triiodothyronine (T3, also called liothyronine). Most people are treated with levothyroxine, or a similar synthetic<unk>  Different polymorphs of<unk> e compound have different solubilities and potencies. Additionally, natural<unk> supplements from<unk> e dried<unk> yroids of animals are still available. Levothyroxine contains T4 only and is<unk> erefore largely ineffective for patients unable to convert T4 to T3.<unk> ese patients may choose to take natural<unk>  as it contains a mixture of T4 and T3, or alternatively supplement with a synthetic T3 treatment. In<unk> ese cases, synthetic liothyronine is preferred due to<unk> e potential differences between<unk> e natural<unk> yroid products. Some studies show<unk> at<unk> e mixed<unk> erapy is beneficial to all patients, but<unk> e addition of lyothyronine contains additional side effects and<unk> e medication should be evaluated on an individual basis. Some natural<unk> brands are FDA approved, but some are not.<unk>  are generally well tolerated.<unk>  are usually not dangerous for pregnant women or nursing mothers, but should be given under a doctor's supervision. In fact, if a woman who is hypothyroid is left untreated, her baby is at a higher risk for birth defects. When pregnant, a woman with a low-functioning<unk> yroid will also need to increase her dosage of<unk>  One exception is<unk> at<unk>  may aggravate heart conditions, especially in older patients;<unk> erefore, doctors may start<unk> ese patients on a lower dose and work up to a larger one to avoid risk of heart attack.
Thyroid hormones
Sex hormone
Gastrointestinal hormone
Hormone
Xenohormone
Thyroglobulin
Thyroid-stimulating hormone
Lipoprotein