Hypothyroidism (a condition characterized by an underactive thyroid gland) is a chronic condition that can be difficult to diagnose. Fortunately, when it is correctly diagnosed, there are treatment options available. Synthroid is one of the most widely prescribed medications for hypothyroidism: it contains levothyroxine sodium, a synthetic hormone that is identical to a hormone that’s naturally produced by a healthy thyroid gland.
Although there’s no cure for an underactive thyroid, Synthroid has proven to be an effective treatment option for most patients. However, a vocal minority of patients have said that Synthroid does not help treat their symptoms, even though their blood test results returned to normal. Recent studies have supported this claim, and top endocrinologists now estimate that 5-15% of hypothyroid patients don’t get better on Synthroid alone.
How Synthroid Works
To understand how Synthroid works, it’s important to understand what the thyroid gland does. The thyroid gland produces hormones that affect your metabolism, which helps regulate almost every system in your body, including your heart, brain, liver, and muscles. If your thyroid gland doesn’t produce enough of the thyroid hormone, you may feel unusually tired, cold, or depressed, and you might experience weight gain, constipation, and other unpleasant physical symptoms.
Synthroid, which contains levothyroxine (hormone T4), is converted to T3 (the active form of the thyroid hormone) in the body’s tissues, which returns the body’s level of thyroid-stimulating hormone to normal and relieves symptoms of hypothyroidism.
Some researchers now believe that certain people may not respond to the T4 in Synthroid due to genetic variations. In their 2014 guidelines, the American Thyroid Association acknowledged that not all hypothyroidism patients improve after taking Synthroid (levothyroxine). The association did not go as far as recommending other therapies but instead recommended that patients be evaluated on an individual basis.
Other Treatment Options for an Underactive Thyroid
There are several other treatment options available for hypothyroidism, although they are not as widely used as Synthroid. Armour Thyroid is made from dried pig thyroids and supplies both the T4 and T3 hormones. Some patients who haven’t responded well to Synthroid say they feel better on Armour Thyroid, but some doctors are reluctant to prescribe this drug because it contains a higher ratio of T3 and T4 than humans normally have and could potentially increase the risk of bone and heart problems.
Cytomel is another possible treatment option—it contains synthetic T3 and is administered in very small doses. It may be prescribed alone or in combination with T4, but results from clinical trials have been mixed. The effects of Cytomel typically wear off fairly quickly because T3 is absorbed quickly in the bloodstream.
If you have been prescribed Synthroid but feel that it has not helped your hypothyroidism, talk to your doctor about other treatment options. Your doctor should be able to look at your medical history and determine which therapeutic approach is best for you.