The synthetic thyroid hormone, Synthroid (T4) is commonly prescribed by many physicians when thyroid tests are abnormal and in many cases doesn't seem to work as effectively as expected. Numerous patients who take their Synthroid as prescribed, with T4 levels in the "desirable therapeutic range" do not feel much significant improvement in their condition. Some even discontinue their medication and feel no significant difference. Increasing the dose of Synthroid sometimes helps, but more often the benefit is greater when either T3 (Cytomel) is added or the patient uses Armour Thyroid (or a similar generic desiccated thyroid), which contains both T3 and T4. [New England Journal Of Medicine, 1999] Many physicians are unaware of this study.

When conversion of T4 to the more active metabolite T3 is inadequate, it becomes especially important to supplement with T3. Some T3 preparations come in a slow-release formula and are taken twice daily for a more even metabolic effect. This is because T3 does not remain active as long in the body as does T4.

In the past it was thought that osteoporosis may be worsened by excessive thyroid hormones. A study demonstrated that osteoporosis is only seen if TSH is left below 0.1 for a prolonged period of time. The goal is to reach an effective dose of hormone while keeping the TSH above 0.1. Many physicians keep the TSH at 3 - 5, which may not result in much clinical improvement.

For purposes of conversion, levothyroxine sodium (T4) 100µg is usually considered equivalent to desiccated thyroid 64mg (1 grain), thyroglobulin 60mg, or liothyronine sodium (T3) 25mcg. However, these are rough guidelines only and do not remove the need to reevaluate when switching thyroid hormone preparations, including a change from one brand to another. Independent testing of generic T4 preparations have found them to be consistantly equal in potency and absorption to name brands like Synthroid.

On a daily basis, whether you take the hormone on an empty stomach or with food is not too important, but there will be better absorption on an empty stomach. Some even take their dose during the night. If you are trying to take your thyroid medication away from meals, consider a separtion period of at least two hours on either side.

You should not take thyroid medications with iron, calcium, supplemental fiber, calcium or aluminum-based antacids or bile-acid sequestering agents (colestipol, cholestyramine) because they will interfere with absorption. Ingestion of soy products simultaneously with thyroid hormones appears to reduce the absorption of the hormones. Bugleweed (Lycopus virginicus, Lycopus europaeus) and lemon balm (Melissa officinalis) may interfere with the action of thyroid hormones and should not be used during treatment with thyroid hormones.

Some doctors trust symptoms over a borderline TSH when considering thyroid medication dose saying that "If patients are going to have normal tissue metabolism and good metabolic health while using T4, most of them must take a dose that suppresses the TSH level. It’s this fact that mainstream doctors need to come to understand."

Additional information on T4 and T3 can be found on Dr. Wilson's web site.