Thyroid Hormone Dosing Dilemnas. Part 1


Several members of metabolism.com have posted their opinions on methods to determine the best dose of thyroid medication for treating hypothyroidism (sluggish thyroid). Many physicians work on the assumption when giving thyroid hormone replacement, that the achievement of thyroid function tests in the normal range, particularly TSH , is the sole indication of an appropriate replacement dose. This is a fair assumption but not every treatment is successful using such rough guidelines. (for more on using TSH levels in the treatment of hypothyroidism see my article here at metabolism.com, “Major Revisions Possible in Guidelines for Diagnosing and Treating Hypothyroidism” ).

To answer the question of when the ideal thyroid hormone replacement dose has been reached, I look at nature’s own experiments. I have treated countless people with diseases of the thyroid resulting in both hyperthyroidism (over-active thyroid) and hypothyroidism (under-active thyroid). Standing out prominently for me is how differently people respond to the presence of either too much or too little thyroid hormone.

Many people visiting metabolism.com express dissatisfaction with their replacement dose for hypothyroidism because they continue to experience symptoms typical of thyroid hormone deficiency (hypothyroidism) on thyroid medication. Their physician is reluctant to increase their dose because the TSH levels are in a normal range. It therefore may come as a surprise to know that in a few office consultations I have encountered people actually preferring to operate with deficient thyroid hormone levels as judged by TSH being elevated in the range 4 to 15. In these instances, increasing thyroid levels by giving thyroid hormone results in symptoms we typically associate with hyperthyroidism such as being excessively hot, shaky, nervous, fatigued and increase in palpitations.

Much more commonly, are those on the other end of the spectrum experiencing symptoms compatible with deficient thyroid levels when thyroid functions tests are in the low end of normal with TSH between 2 and 4. Symptoms in this group may include fatigue, puffiness, lack of concentration, weight gain, cold, muscle cramps and achiness, and constipation.

The diversity in symptomatic response to hyperthyroidism (thyroid hormone excess) can be equally broad. I can think of numerous individuals who are not the least bit troubled by extremely elevated thyroid level never experiencing typical symptoms such as feeling hot, shaky,sweaty etc. One might suspect that these people are just a tough breed of non-complainers. But checking for typical signs of hyperthyroidism which are independent of personality such as tremor, or rapid heart rate yields totally negative results. Others however, with just the slightest excess of thyroid hormone are plagued by feeling worn out, anxious, sweaty, hot with markedly elevated heart rates and tremors.

What could explain the wide variation between individuals, in response to thyroid hormone levels? In Part 2 of this article I will explore some of my thoughts and theories, while, as always, I invite members to join in with their own experiences.

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  • gina

    Dr. Pepper, you ask “What could explain the wide variation between individuals, in response to thyroid hormone levels?” However, throughout your post, you actually only discuss TSH, the pituitary artifact, rather than measurements of actual thyroid hormone levels, free T3 and free T4 in particular. TSH has never been shown to consistently predict actual thyroid hormone levels in individuals; to the contrary, a given TSH level may correspond to widely disparate throid hormone levels in two individuals or even to the same individual at different points in time. Perhaps you are correct that some individuals tolerate deficient or elevated levels of thyroid hormones without hypo or hyperthyroid symptoms. However, if the only evidence supporting your theory is “thyroid hormone levels as judged by TSH”, then you have no evidence at all.

  • Dava Michelson

    Please discuss how you treat Hashimoto’s specifically. Thank you.

  • sheila

    I agree with Gina about the free T3 and T4 and testing their levels also.

  • Michelle Ritz

    I have just been diagnosed with Grave’s disease (hyperthyroidism). I have all of the symptoms except that I continue to gain weight. I am on a low calorie diet (1200-1400 calories) per day.
    What can I do?

  • Hank Frier

    In regards to getting around the FDA’s insistence of an New Drug Application, the simplest route for Forest and other ethical pharmaceutical companies is to go the dietary supplement route. Under the DSHEA regulations the FDA would have no control over the OTC selling of this compound. The only rule is that the companies use a structure/function claim rather than a claim to mitigate or prevent disease. Since Armour is a natural product the creative minds at Forest should be able to come up with a structure function claim and sell it OTC without FDA intervention.

    I am surprised that Forest has not thought of this route unless they would rather sell their synthetic which for me as well as Synthroid does not work re: your comments on the genetic variants that exist.

    Hank Frier, PHD

  • I need some help or input..I had a perfectly function tsh level up until I had my complete hip replacement almost 4 years ago. Prior to the surgery my tsh was l.63, l.7, l.59 and l.l7 Then post op and ever since which is almost 4 years now it has been .0.43 and now 0.34 .Despit the fact that I am on 60 mg. of Armour thyroid I CANNOT get it up..and I am displaying ALL the signs of hyperactive thyroid..Can anyone help me out. My T4 and T3 are normal it is ONLY the TSH that is consistently subnormal..ANY help would be sincerely appreciated.