If you're on thyroid hormone replacement, have a TSH level that's in the normal range, and are still having a range of thyroid-related symptoms, you may be one of the millions of thyroid patients suffering from undertreated hypothyroidism and can benefit from a discussion with your doctor about optimum TSH levels and thyroid drug options.
What is undertreated hypothyroidism? It's hypothyroidism at the cellular level that means you still have hypothyroidism symptoms such as fatigue, weight gain, depression, fibromyalgia/muscle & joint aches and pains, hair loss or coarse/dry hair, infertility and more --despite taking thyroid replacement and having a "normal" TSH level.
There are two reasons this can occur. First, some doctors believe that providing only enough thyroid hormone to get a patient to mid to high-normal TSH levels is sufficient. And second, the current standard treatment, levothyroxine (brand names include Synthroid, Levoxyl, Levothyroid, Eltroxin, Euthyrox) may not be enough for the majority of people to actually feel well, because the body also needs a small amount of the hormone T3 in addition to the levothyroxine in order to truly feel well.
The endocrinologist I see periodically, as well as my regular physician, both believe that a TSH of around 1 to 2 is optimal for most people to feel well and avoid having hypothyroid or hyperthyroid symptoms. There is also research that suggests that values above TSH of 2 may actually even represent abnormal levels. See the British Medical Journal for more information on that research.
And as of March 2003, it is the official recommendation of the america Association of Endocrinologists that the normal range for TSH levels is .3 to 3.0 -- Read the information here. I know I feel terrible at a TSH level of 4 to 5, I also feel bad when it drops too low to .2, but I pretty best at a TSH of between 1 and 2.
(NOTE: TSH levels are usually kept lower than 1 to 2 for thyroid cancer survivors -- a process known as thyroid suppression -- to help prevent cancer recurrence.)
TSH Less than .5/.7 -- This is considered hyperthyroid (too much thyroid hormone) at most labs in the U.S. You may be anxious, find it hard to sleep, hair falling out, diarrhea, and other symptoms
TSH 1 to 2 -- The optimal normal level for most people. This is the TSH range where the majority of people feel best. It is sometimes considered "too low" by less-informed doctors.
TSH 2 to 4.7/5.5 -- "Normal" range according to some lab standards, but the recommended top end of the range was changed as of March 2003 to 3.0 Some people feel well in this range, but many suffer low-grade hypothyroidism symptoms at this level.
TSH 4.7/5.5 to 10 -- Formerly considered "subclinical hypothyroidism" levels, but as of March 2003, above 3.0 is considered evidence of possible hypothyroidism. These levels show hypothyroidism, but amazingly, some doctors won't even treat these levels, and do not attribute hypothyroidism symptoms felt by patients at this level to the hypothyroidism itself. Many people have symptoms at these levels.
TSH Above 10 -- Considered hypothyroid that merits treatment by most doctors
The Need for T3
Some people do not feel well on a levothyroxine/T4 only drug (like Synthroid). I am one those people who feels far better taking T3. I take the drug Thyrolar, and it has worked far better for me than Synthroid. Others have had success adding T3, such as in the form of Cytomel or via compounded, time-released T3, to their levothyroxine. Finally, yet others have had success with Armour, the natural thyroid hormone replacement. For more information on the various thyroid drugs, see A Quick Look at Thyroid Hormone Replacement, and Armour Thyroid and Thyrolar: Alternatives to Synthroid and the Other T4-Only Drugs.
Surprisingly, It's still considered controversial to use T3 for people with hypothyroidism by the less innovative or accepting members of the medical world, despite research that clearly demonstrates the need for T3 in many thyroid patients. In February 11, 1999, the New England Journal of Medicine published a groundbreaking research report that says that many patients feel better on a combination of T4 and T3, not T4 (i.e., Synthroid) alone. Many people have a normal or even LOW-normal TSH level, yet still suffer continuing hypothyroidism symptoms. In these cases, the addition of T3 helped relieve depression, brain fog, fatigue and other symptoms. This information about T3 is quite revolutionary and has major implications for people who don't feel well on their current thyroid therapies!!! For more info, see my full report on this research.