For borderline underactive thyroid, drug therapy isn’t always necessary

I’m always amazed to see just how many problems a slowdown in the output of the thyroid gland can cause: extreme fatigue, intolerance to cold, weight gain, dry skin, and dry hair, to name a few. Millions of Americans have an underactive thyroid, a condition known as hypothyroidism. That means this butterfly-shaped gland doesn’t produce enough thyroid hormone to regulate metabolism, causing many body functions to become sluggish. The resulting symptoms are no picnic, but they’re usually ones that can be controlled with a daily dose of a thyroid medication, a synthetic thyroid hormone called levothyroxine (generic, Synthroid, Tirosint, others).

Experts don’t always agree on when to start thyroid medication. Many people may be taking thyroid medication unnecessarily. Over prescribing of levothyroxine may be triggered by how laboratories report results of thyroid hormone levels, as well as physicians prescribing levothyroxine to treat symptoms that aren’t actually due to hypothyroidism.

Endocrinologist Dr. Jeffrey Garber, an associate professor of medicine at Harvard Medical School, agrees with the findings. He’s an internationally respected authority on thyroid disease, and author of The Harvard Medical School Guide to Overcoming Thyroid Problems. He says a number of factors may be contributing to the increase in treatment of mild hypothyroidism. “Greater patient and physician attention to thyroid status may be prompting more testing and leading to more diagnoses,” he says. Plus, he points out, the threshold of what’s considered a normal thyroid range was lowered in 2002, and that lower number is what labs use today when they look at thyroid hormones in the blood.

Maybe that’s why prescriptions of levothyroxine increased in the U.S. from about 50 million in 2006 to about 70 million in 2010. Researchers found a similar increase in England and Wales, with prescriptions jumping from 17 million in 2006 to 23 million in 2010.

What’s wrong with giving people who have a borderline underactive thyroid a little thyroid medication to make them feel better? Well, it’s a pretty risky business. They run the risk of experiencing side effects from taking levothyroxine, which include irregular heart rhythms, insomnia, and loss of bone density, without reaping any benefit from it.

The best way to check for hypothyroidism is to look at the level of thyroid stimulating hormone (TSH) in the blood. That’s the hormone the pituitary gland sends out to tell the thyroid how much thyroid hormone to release. If the thyroid is underactive, the pituitary gland will tell the thyroid to work harder, and it does that by sending out more TSH. So the higher the TSH level, the lower the thyroid activity. A normal TSH value is under 4.0 milli-international units per liter (mIU/L). When the TSH level is above 10 mIU/L, there’s uniform agreement that treatment with levothyroxine is appropriate.

If the TSH level is between 4mIU/L and 10mIU/L, treatment may still be warranted in various situations:

  • if the levels of actual thyroid hormones in the blood—known as thyroxine (T4) and triiodothyronine (T3)—are abnormal
  • if the bloodstream contains anti-thyroid antibodies that attack the thyroid. These antibodies would indicate a hypothyroid condition called Hashimoto’s disease, in which the immune system mistakenly attacks the thyroid.
  • if there is evidence of heart disease or risk for it.

What should you do if you have borderline low thyroid levels that cause uncomfortable symptoms but don’t meet the guidelines for treatment? “Use thyroid hormone for a brief period of time,” recommends Dr. Gerber. “If you feel better, you can continue with treatment. If not, then stop.”

All treatment for hypothyroidism, even borderline cases, must be individualized and monitored carefully by a physician. That requires measuring TSH four to eight weeks after starting treatment or changing a dose, another TSH test after six months, then every 12 months.


  1. Minimum

    I am a 63yr old female, and have been taking Thyroxine for years, my new Gp increased the dosage after I complained of being tired all the time and simply not having any energy, and those energy levels waning even further after a bout of radiotherapy for breast cancer. This last week I have experienced chest pains and the past few weeks I have had continual headaches. After a visit today with my GP he has suggested I stop taking the thyroxine and we will see what happens. Hopefully I will feel better and gain some energy and be rid of feeling like crap all the time and somehow lose some weight which despite diet and exercise I am unable to move!!

  2. Jenny

    I love this article. I have stopped taking my meds and I don’t feel like I have thyroid illness anymore. The effects of synthetic medicine can be really serious, and that’s what alarmed me. I then turned into eating healthy, changed my lifestyle and I feel better. Although I still find it hard to gain weight, but I think I’m getting there. What’s important to me is that I feel better, and that helps a lot psychologically. You can read about my struggles in health at my blog,

  3. Jill Bruch

    I just found out I’m on the borderline of Hypo thyroid…My levels came out 2.2…She said I should go on medication?Just was trying to get a second opinion…I due have symptons forsure….

  4. Valentin Fernandez-Tubau

    Very interesting article and fascinating controversy. On the other hand, Maria da Graça Campos states main bioactive compounds of soy are isoflavones and those can induce hypothyroidism. This relationship is also a subject of interest and further investigation. Finally, in the field of psychology, we know of too many cases who were wrongly diagnosed with depression, missing out the fact they suffered from hypothyroidism. In this regard, something beyond the use of levothyroxine may be in question: the use of antidepressants or even cognitive therapy, which should be replaced with a correct diagnosis and a proper treatment for hypothyroidism.

  5. Joan Lowe

    “It is critical that the patient’s thyroid hormone dosage not be adjusted based on an ‘ideal’ mid-range TSH level. Doing so almost guarantees a failed therapeutic outcome. Many clinicians mistakenly believe that the TSH level correlates with tissue metabolic rate. The TSH level and metabolic rate are out of synchrony in many, and perhaps most, patients. We have found no studies documenting a reliable correlation between the two.” Dr John Lowe

  6. Helen Wright

    A perfect blog.. simple to read and understand about the common disease “Thyroid”. Majority of them are affected by this and are not much aware of the true condition. This is a wonderful blog with all necessary information.

  7. al

    Great article and comments…what is the optimal ranges for free T3, T4 then?

  8. Sharon Hagen

    It is just this kind of ridiculous, unscientific, limited thinking that has kept me ill and with frightening increasing symptoms of hypothyroidism since at least 2005. My TSH is “fine” and in fact has never gone above 1.89. This apparently made it OK for 6 endocrinologists to tell me that my bottom range FT4 and FT3 were immaterial and that my symptoms were either “from other causes” (WHAT causes were of course never specified) and that really, it was “all in my head.” I was sent to a psychiatrist who pumped me full of mood-altering drugs that made me puke my guts out but did nothing for the increasing depression and panic attacks. Funny how my bone density INCREASED on a combined T4/T3 regime given me by my primary care physician, concerned and willing to treat the symptoms that ALL pointed to lack of thyroid hormones. Funny how my elevating blood pressure and glucose and cholesterol went back to normal almost immediately upon being given T4/T3. Funny how the brain fog and depression and anxiety attacks went away within less than a week of having T3 added to the T4 that was doing little for me. Funny how the thyroid nodules decreased in size. Funny how I lost 15 lbs. in 3 weeks after being given T3, and another 10 in the following 2 months without change in diet or exercise. Can you spell myxedema ? Those 6 endocrinologists fought against me taking T3 of course. When various endocrinologists lowered it after blood tests were done IN THEIR OFFICES a couple of hours after I had taken the T3 ( against all protocol and of course coming back high), I immediately has resumption of symptoms and immediate 15 lb. weight gain. I believe they have permanently destroyed my metabolism. And guess what ? After high-out-of-range rT3 sent me seeking even help for the return of symptoms and my PCP didn’t know anything about rT3, a doctor of functional medicine… NOT an endocrinologist… finally sent me for an MRI, which I had asked for for years because the seeming thyroid problems started following 2 rear ended car accidents in 11 months with whiplash and concussion. And WALLA ! Turns out my thyroid problem IS all in my head, just not the way those endocrinologists meant it. I have a pituitary adenoma. TSH ain’t HAPPENING, in my case, just as I suspected. However, endocrinologists told me secondary hypothyroidism is “rare” and tissue resistance (which I also apparently have, along with elevated cortisol and erratic ACTH) doesn’t exist, so I couldn’t possibly HAVE it. Not even worth testing, and the high cortisol “wasn’t that high out of range.”

    Articles like this one are harmful to patients.

  9. Leigh Bennett

    Ms. Godman: This article is an un-scholarly parroting of misinformation spread by the PR team hired years ago by Abbott Labs to boost sales of its pharmaceutical product, Synthroid. A bit of Woodward&Bernstein-style investigative research would uncover the sad history of this ruse.

    The unexamined professional acceptance of the mis-information is an example of what in the field of Behavioral Economics is known as a “Cascade,” whereby individuals observe others’ behavior and copy it, rather than independently studying available information and deciding how to act. Several years ago, in fact, The Harvard Alum magazine itself reported findings by medical watchdog organization HealthGrades, wherein upwards of 95% of physicians admitted to relying solely on information provided by pharmaceutical company salesmen, doing absolutely no independent research, when prescribing drugs for their patients.

    And it’s no wonder that sales of Synthroid jumped between 2006 and 2010: for those of us who got no effect from the synthetic but have thrived taking desiccated porcine thyroid–the gold standard for about 100 years until Abbott Labs started selling its (vastly inferior) synthetic product–our drug of choice was suddenly and mysteriously made unavailable in the US in 2007, forcing the wilier patients to fill prescriptions through international pharmacies, but, no doubt, many, many patients simply threw up their hands and switched to the synthetic. I recall it took at least a year for natural desiccated thyroid to get back into the pipeline in the U.S., while there was never a shortage of any sort at that time anywhere else in the world. Neither the FDA nor the manufacturers ever favored consumers with an honest explanation of the SNAFU; though it was revealed that members of the central advisory board at the FDA had close ties to pharmaceutical companies. The inherent conflicts of interest somehow remind me of the deferential treatment Bernie Madoff received from the SEC. So much for government regulation–*sigh*!

    As for proper and effective treatment of hypothyroidism, your first commenter, “Joan Lowe,” is right on target. TSH tests the pituitary gland, not the thyroid and while yes, there is a feedback mechanism between the two glands, testing TSH production is only an indirect indication of the function of the thyroid. The proper test of thyroid function is not merely total T4, but FREE T4, that is, the thyroxine actually circulating in the blood available for use by the organs in the body. Bound T4 is of no practical use in the body; so even if the total T4 appears within range, that number could mask a significantly sub-par level of FREE T4. Coincidentally, this was the exact result on my most recent blood test: low TSH, total T4 in range, FREE T4 well below range–not to mention, clear clinical symptoms–ergo, need to raise my supplement dose.

    Additionally, one of the great and under-diagnosed problems with hypothyroidism is that often the sufferer has limited ability to convert T4 to its active form, T3, so testing of T3 levels is also critical. If the patient has limited ability to convert thyroxine (T4) to triiodothyronine (T3), no amount of T4, synthetic or natural, will restore her health.

    It is an enormous problem for hypothyroid women who are facing the uneducated bias held by the preponderance of endocrinology specialists: if the synthetic drug brings the TSH number and the total T4 into range, regardless of clinical presentation, the woman’s discomfort will be dismissed with, “well, the drug isn’t perfect, it doesn’t cure everything.” And yet, a vast population of women who switch to the traditional and time-tested desiccated porcine product (which provides the full spectrum of T4 and T3) enjoy a near-complete remission of their symptoms.

    I would urge you to go back and take up a critical re-examination of the issue of hypothyroid diagnosis and treatment. Especially because the majority of sufferers are women, and even today in our sexist society–as many strides as we have made since the 1970s, indeed sexism certainly persists in American culture–too often women’s health issues are dismissed with, “the doctor knows best, dear: it’s all in your head.” Let’s see if we can put this one women’s issue behind us, and move forward to our next challenge with strength, in good health!

  10. Deb Beggy

    Agree with Joan Lowe that focus on TSH is ludicrous…and outdated. My thyroid was sluggish, as indicated by weight gain,cold extremities and body temps that were slightly below ‘normal’, fatigue with sleeplessness..and other symptoms often attributed to middle age…yet my GP MD had failed to diagnose hypothyroid because TSH was “perfectly normal”. Very frustrating to be told to “eat less and exercise more,” That was 3 years ago: thankfully an ND pointed the way with blood testing that looked at additional components Free T3 T4! My treatment of Armour Natural Thyroid has successfully alleviated those symptoms – and my weight easily lost; now back to normal – after years of cchallenges.I wanted to share two books I found Along the way: Dr Mark Starr’s amazing and worthwhile Hypothyroidism Type 2, The Epidemic and another by Janie Bowthorpe, Titled Stop The Thyroid Madness.

  11. Joan Lowe

    I believe the “lack of benefit” seen in many patients is due to the lack of efficiency of the medicine – not because the patients are not in need of treatment or indeed would benefit hugely if treated correctly and with the correct medicine. Thinking that testing the blood’s content of thyrotropin is the best way to determine the level of thyroxine (T4) and triiodothyronine (T3) available to the body is absurd! Not to mention to total lack of regard for the presence of reverse triiodothyronine which is a known issue for many patients. This is SUCH a complex issue with an infinite number of variables affecting the patients – environmental, nutritional deficiencies, medications, genetic factors and so forth – that focusing solely on TSH seems so ludicrous I find it hard to comprehend how it’s become mainstream!

  12. Maria da Graça Campos (Faculty of Pharmacy University of Coimbra - Portugal)

    Thank you for the important overview of this situation. My concerns go to the cause and in our opinion the excessive consuption of products based in soy could be something that we should check.
    The main bioactive compounds of soy are isoflavones and those can induce hypothyroidism. Other countries as Brazil also have these increase of thyroid problems.
    Is urgent that we found the cause to prevent this situations in the future, and probably for some people this could be reversible.

    • A. Greenwell

      I am very interested to learn about the interaction you have found with consumption of soy products and would welcome some references on the topic.

  13. Markus Frauchiger

    Great article Heidi! Thanks a lot! I also think that many people may be taking this medication unnecessarily, and the side effects of thyroid medication can be seriuos. Individual treatment is absolutely necessary. Great to know that other think alike. Thanks again,

    Kind regards,

    Markus Frauchiger

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