Runa Acharya, MD. Amy Patel, MD. Select Format Select format. Permissions Icon Permissions. Abstract Treatment of hypothyroidism is predominantly with levothyroxine due to its ability to generate stable T3 levels and its long half-life.
For commercial re-use, please contact journals. Issue Section:. Download all slides. View Metrics. Email alerts Article activity alert. Advance article alerts. New issue alert. Receive exclusive offers and updates from Oxford Academic. Levothyroxine is the main thyroid hormone produced by the thyroid gland and the synthetic form is the most common form of thyroid hormone replacement therapy. Prior to the availability of the pure levothyroxine, desiccated animal thyroid extract was the only treatment for hypothyroidism.
In addition, some patients who continue to have symptoms of hypothyroidism when taking levothyroxine report improvement in these symptoms when switched to desiccated thyroid extract. This study was performed to compare levothyroxine to desiccated thyroid extract in terms of thyroid blood tests, changes in weight, psychometric test results and patient preference. J Clin Endo- crinol Metab ; Epub March 28, However, these components are not thought to have any significant effects in the body.
Synthroid is the brand name for a synthetic thyroid medication also known as levothyroxine sodium. It contains only synthetic T4, which is biologically identical to the T4 produced by the body. Once ingested Synthroid is converted by the body into T3, the active thyroid hormone. There is an additional thyroid medication called liothyronine.
Armour Thyroid and Synthroidare the two main medications used to treat hypothyroidism. There is also a third type of medication made of synthetic T3. Desiccated thyroid extract was the original medication used to treat hypothyroidism. During this time, thyroid hormones were not completely understood and there was a lack of reliable diagnostic tools blood tests to measure circulating levels in the blood.
As a result, the dosage was often too high and serious side effects were often reported. Also, due to inconsistencies in the strength of medication, some people were not seeing any improvements. Conversely, Synthroid levothyroxine was thought to offer a safe and consistent dosage. Two things lead to this switch:. Summary: Desiccated thyroid extract was the first type of medication used to treat hypothyroidism. Eventually, a synthetic T4 medication was created and found to be a safer and more effective option.
Synthroid levothyroxine is the recommended treatment for hypothyroidism and prescribed by most doctors. The American Thyroid Association along with other international thyroid organizations agree that Synthroid is the most effective treatment option.
There is no strong evidence to suggest Armour Thyroid or a combination therapy of synthetic T4 and T3 produce better results than Synthroid in most people 1. The European and American guidelines also acknowledge that experimental use of synthetic T3 may benefit some people. This will be discussed in more detail below. Summary: Current thyroid association guidelines recommend Synthroid as the first treatment option.
There is little evidence to support the use of Armour Thyroid over Synthroid. Anecdotal personal reports claim Armour Thyroid leads to increased feelings of wellness and reduced symptoms as compared to Synthroid. In a double-blinded study of 70 participants, those taking Armour Thyroid lost nearly three pounds more than those taking Synthroid. This may have to do with genetics. Some people with specific genetic mutations may not be able to either convert T4 into T3 or transport T3 in and out of cells from the blood.
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