Borderline thyroid tests: When should you take thyroid medication?

January 27, 2011 81 Comments by Scott Isaacs MD

A recent study found that many people have untreated thyroid disease.  The study, published in the Journal of Medical Screening assessed over 4000 people between the ages of 50 and 65 and found about 8% have low thyroid levels.  When weight goes up, many people suspect a low thyroid.  But when they go to the doctor, they get the routine “TSH” test and are told “it is borderline” and probably not the problem.  As an endocrinologist, I see this frequently.  There are so many cases with borderline thyroid testing where the thyroid really was to blame.  Once treated, thyroid patients lose a lot of weight without a major change in their diet or exercise routine.

Thyroid experts recognize the TSH test as the test of choice when thyroid disease is suspected.  An elevated TSH test diagnoses hypothyroidism.  TSH is more sensitive than other thyroid tests because it begins to rise before thyroid hormones drop.  As such, it’s a better indicator of early thyroid dysfunction.

When the TSH test is “high normal,” in the range of 2.5-4.5, deciding to take thyroid medication can be a difficult decision.  I’ve seen many patients with this situation.  Frequently, thyroid tests in this range will normalize within a few months, other times, they progress to overt hypothyroidism.   The first step is to repeat the test.  I never make a treatment decision based on a single blood test.  Experts recommend waiting 3 months to repeat a borderline abnormal TSH test, but if you have a lot of symptoms it is better to do it sooner.

In my opinion, many doctors take the easy way out and prescribe a low dose of thyroid medication when the thyroid is really normal.   If you take low dose thyroid hormone and your thyroid is normal, it will make fewer hormones to maintain normal levels.  So taking a low dose of thyroid hormone, even if you don’t need it may not do much.  I’ve seen so many patients who have tried this approach and then come to me still complaining of symptoms.  Some of these patients stopped thyroid hormone replacement and felt better.  Others do feel better, but I have always wondered how much of this was placebo effect?  A study was done to determine if treatment with thyroid hormone could improve the symptoms of hypothyroidism in people with normal thyroid function tests.  The results, published in the British Medical Journal, showed that thyroid hormone was no more effective than placebo for relieving symptoms.

On the other hand, some people with borderline tests have early thyroid disease that is certain to progress.  Diagnosing hypothyroidism in the early stages can be tricky.  That’s because when the thyroid starts to fail, tests can remain in the normal range for a period of time.  The first thing that indicates low thyroid is an elevated TSH level.  A change from a low normal TSH to a high normal TSH over a period of a few months may mean early thyroid failure.  If thyroid antibodies are positive or if the thyroid gland is enlarged the risk for thyroid failure is extremely high.  If the thyroid antibodies are normal and the thyroid is not enlarged, the risk is much lower.

The bottom line is that many times there is no easy answer.  If the thyroid is truly to blame, tests will become more clearly defined as time goes on.  There is usually no harm in waiting a few months to make a decision about treatment.

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  1. Cynthia Woodson says:
    Sunday, July 22, 2012 at 8:36pm

    I am so thankful I found this article. I have been dealing with all the symptoms listed above and then some but to only get an elevated but NORMAL “TSH” levels. I exist on 1200 calories a day andphysical work after 5 months, lost 0 pounds. My endocrinologist has no empathy, nor does she has no empathy but not look at symptoms at all. I would like guidance on how to get help so I can get my life back!

  2. Scott Isaacs, MD says:
    Monday, July 23, 2012 at 8:15am

    I hope my book can help you.

  3. sylvia says:
    Saturday, September 15, 2012 at 7:07am

    I had tsh done in 2009,it was 5.5. Then skipped 2010 and 2012 my tsh was 5.8 should I take the thyrozine meds Im 60 and am hesitant on taking another pill. I m on bp pills,HTCZ,Lisniopril,40mg,generic coreg,12.5 twice a day,81mg aspirin.I feel good,am overweight,276 lbs. Thank You for your advice,oh another question,do I stay on the meds for the rest of my life?

  4. Scott Isaacs, MD says:
    Tuesday, September 18, 2012 at 3:07pm

    Sylvia, Your TSH is borderline elevated (which means thyroid levels are slightly low). I recommend seeing an endocrinologist who can adjust the dose of your thyroid medication to get your hormone levels into the normal range.

  5. Eva says:
    Saturday, September 29, 2012 at 9:40pm

    Over 10 years ago, I was disagnosed with hypothyroidism. In early Sept. of this year, I began showing symptoms of hypothyroidism again (weight gain, fatigue, brittle nails, hair loss, hives, feeling of a lump when swallowing, etc.). My doctor said that my TSH range is 2.93, T4 Free 1.1 and T3 Free is 3.0. I was diagnosed as being vitamin D deficient and was told that my thryoid is fine. The vitamin D seems to have given me more energy but my hives have gotten worse and the fatigue is creeping back along with other symptoms. Are my levels considered borderline for hypothyroidism? I’m not sure how long I should wait to see an endocrinologist.Any advice?

  6. Eva says:
    Saturday, September 29, 2012 at 9:55pm

    I forgot to mention that I took medication for hypothryroidism years ago but was taken off of it because my levels were fine at that time, I gave that information to my doctor before my TSH levels were checked, My doctor seemed to appreciate the informatiion but seemed to be steered more towards a vitamin deficiency.

  7. Scott Isaacs, MD says:
    Sunday, September 30, 2012 at 8:54am

    Making a diagnosis can be a challenge. Your levels seem OK, but there is a lot more to making a diagnosis than those numbers. I would see an endocrinologist now.

  8. Eva says:
    Wednesday, October 3, 2012 at 10:57pm

    Thank you for answering my questions. I wasn’t sure what I should do. I trust my doctor but I also know that some of my symptoms seem to be getting worse so I’m curious to see what the endocrinoligist will find. I’ll be making an appointment to see one very soon.

  9. Elena says:
    Saturday, October 6, 2012 at 10:52am

    This article was indeed a lifesaver. I am ordering the book now and plan to recommend it to many others I know with this problem! I am frustrated because my TSH is normal, but My free T4 (.56) and Free T3 (1.7) continue to be low. I am about to start nature-throid, but would like your opinion, Dr Isaacs. Thank you so much.

  10. Scott Isaacs, MD says:
    Monday, October 8, 2012 at 9:26am

    Thanks for your kind words. Nature-throid is an option, if you want to take desiccated porcine thyroid. Here is a link to my article about alternative thyroid medications.

  11. Sakura says:
    Friday, December 21, 2012 at 1:51pm


    I was having frequent throat infections and i was under medication frequently because of the tonsils that i had. since i was becoming a bit pulpy the ENT asked me to take thyroid test.

    I was first diagnoised with TSH level 5.67 and my scan showed bilateral thyroid. then we went to a endocrynologist he said lets wait for 2 more months, but unfortunately my mom forced me to meet another doc since the enlargment in the neck was obviously out a little bit. then tey took the tests and said the levels are normal in blood need to take FNAC. we did tat and found tat it was hashimotos thyroidites. then i was under medication with does of 37.5 mg. by chance i cheked the BP and found tat it was fluctuationg like anything. my cardio asked me to stop the pills and gave me BP tablets. then my bp came to stable as 130/80.they asked me to take general tests. in that everything is normal and the TSH level is now 2.68 and T4 is .1 more than the normal level. Could you please advise me on this. I feel i should have waited for 2 more months that my first doc asked me to. now i am feeling why i started with the pills and i dont know which doc should i trust. Please guide me on the same.

  12. Scott Isaacs, MD says:
    Friday, December 21, 2012 at 1:54pm

    Sakura, definately work with your physicians to make sure your thyroid levels are in the normal range. I wish you the best.

  13. Sakura says:
    Saturday, December 22, 2012 at 4:10am

    Thank u. i will defantely meet a good physician to get my health bak in good condition.

    i have a doubt regarding the thyroid medication i heard that once i start the medication i can never stop it even if norma level is maintained. is it really true that we cant stop taking medications and once we start taking the medication the body will stop producing the harmones on its own??

  14. Becky says:
    Wednesday, February 13, 2013 at 11:41pm

    My TSH test last year was 4.29. I just got the result of this year’s test and it is now 7.227. I revisit my doctor next month. My mother has hypothyroidism and she takes medication (that the dosage was recently raised again). I’ve been trying to lose weight these last 2 years – unsuccessfully -and have actually gained 30 pounds in this past year. Is it safe to assume when I see the doctor next month that I will be put on medication? Or should I request further testing?

  15. Kathy Kealey says:
    Saturday, February 23, 2013 at 3:19pm

    My TSH is 6.66 and my Free T4 is 12 – I have been prescribed a low dose 25mcg synthroid medication with retesting in 3 months. I had wright gain and fatigue with some mild depression but I don’t understand the statistics – is a TSH of 6.66 borderline and whst dioes the Free T4 number mean ? Many thanks for your informative comments

  16. krishna says:
    Thursday, February 28, 2013 at 4:23am

    i m 2 months pregnent n my TSH test was 4.75 .. so my gynecologys doctor told me that you have to take thyroid medicine 25gm half tablet in morning then after 10 day you have to take 1 tablet. So i want to know that should i take the medicine or not?

  17. Lakshmi says:
    Friday, March 29, 2013 at 9:54pm

    Hi, i read your articles online and would like your opinion. My mother is a diabetic but under good control with HBA1C around 8 and has her TSH levels at 3.7. The doctor has prescribed medication but she is reluctant to take medication when it is not required. Kindly advise at what levels should she start taking pills?

  18. Lakshmi says:
    Friday, March 29, 2013 at 10:06pm

    My mother’s age is 56 and she has been a diabetic for the past 13yrs. She has recently done a master check up and all other values are in the normal range except hemoglobin level and RBC which are slightly below normal. So should she take the pills for throid?

  19. Rocio says:
    Sunday, March 31, 2013 at 9:30pm

    I have low thyroid and started to gain weight I’m starting to get depressed because I see no results with medication. I would like to know if anyone has got results with anything else or if I should expect the Worst.

  20. Chiara says:
    Friday, April 12, 2013 at 10:56am

    Hi, I’m italian girl, 24 years old who is 41 kgs weight. My Ths is 4..35 on 4.5 of max range and my end told me is a rather normal bprderline TSH. Can hyphptyroidusm create a situation of a underweight? Or always TSH make a weight gain? Thank you and sorry for my english ^^`

  21. Scott Isaacs, MD says:
    Friday, April 12, 2013 at 12:31pm

    Complicated situation. A lot of variables, I advise working closely with an endocrinologist who can address the big picture. I wish you the best.

  22. Scott Isaacs, MD says:
    Friday, April 12, 2013 at 12:33pm

    When you say no results, do you mean your thyroid levels are still low even though you are taking medication? Or do you have symptoms despite normal thyroid levels?

  23. Scott Isaacs, MD says:
    Friday, April 12, 2013 at 12:33pm

    Thyroid testing is necessary to diagnose a thyroid problem.

  24. Scott Isaacs, MD says:
    Friday, April 12, 2013 at 12:34pm

    I would not say that A1c is “good” control. The American Diabetes Association considers A1c of 7% controlled. Above that number is considered uncontrolled.

  25. Scott Isaacs, MD says:
    Friday, April 12, 2013 at 12:36pm

    Thyroid disease in pregnancy can be complicated. It is a good idea to work closely with an endocrinologist.

  26. Scott Isaacs, MD says:
    Friday, April 12, 2013 at 12:37pm

    My book Hormonal Balance has a detailed decription of the various tests used to diagnose thyroid disease. The free T4 is used in combination with the TSH test to make a diagnosis and to assess the severity of thyroid disease.

  27. Scott Isaacs, MD says:
    Friday, April 12, 2013 at 12:54pm

    Further testing is needed, I discuss the details in my book Hormonal Balance. Some people with your numbers end up having normal tests a few months later, but most people progress and need medications. I wish you the best.

  28. Dawn says:
    Saturday, April 27, 2013 at 6:14pm

    Hi! My TSH came back as 2.68 and my T4 is 1.25. I am on 100 mcg Synthroid, and I feel great! Just wondered if I was still in the right track? Thanks!

  29. Retha Godbey says:
    Friday, May 3, 2013 at 3:00pm

    Hi Dr. Isaacs!
    I’ve been trying to get pregnant for 2 years now and I just found out that I have tested positive for thyroid antibodies, but my TSH is normal, 1.74. What do you think is causing this? My fertility doctor doesn’t think that I have an autoimmune disorder. Should I see a thyroid doctor?


  30. Joann says:
    Saturday, May 4, 2013 at 10:17am

    Hi. Thank you for your site. Help. I really need advice. I think I am having hypo symptoms of leg cramps, knee pain, and heart palps that I have never had – generally now associated w/menstrual period. I am 46 yrs old.. General physician tested and said levels are normal and my insurance requires his referral for an endocrinologist. Here are my numbers: Free T4: .9; TSH: 1.82; Free T3: 2.7; Total T3: 1.0; Vit D 25-Hydroxy: 38.71. Thank you for your time…if levels are o.k. but low normal, would extra Vit D help??

  31. Scott Isaacs, MD says:
    Tuesday, May 21, 2013 at 1:06pm

    Thyroid antibodies can increase the risk for a miscarriage, even if your thyroid levels are normal. Calling this a “disorder” or “condition” is simply the language the doctor is using. I do recommend seeing an endocrinologist, as your risk for developing low thyroid is higher than average. Here is a link so you can find an endocrinologist close to home.

  32. Krista says:
    Tuesday, June 4, 2013 at 2:58pm

    Hi Dr. Isaacs,
    I am hoping for a bit of advice. I was put on thyroid medication a few months ago (50mg) after being diagnosed with hypothyroidism. My levels seem to be fine (1.43 TSH), however I have started to experience my original symptoms again. I am swelling under my eyes & in my legs (below my knees). My endocrinologist told me to see my regular physician & my physician told me to go back to my endocrinologist… I’m at a loss. Do you think these symptoms could be thyroid related? Thanks for your help!

  33. Rose says:
    Tuesday, June 11, 2013 at 12:08am

    Hi Dr. Isaacs my TSH level came back as 4.68, T4 .073, T3 2.67. My doctor said it’s mild, and gave me a prescription of synthroid 50mg. But after doing some research on my own I believe that 50mg for a mild thyroid is a high dosage. My friend is also hypo she was borderline hypo and was put on synthroid 25mg and after taking synthroid 25mg her thyroid level went out of whack now her thyroid level is high.
    Do you have any advice for me?

    Thank you,

  34. Scott Isaacs, MD says:
    Friday, June 21, 2013 at 11:20am

    Everyone is a little different. Work with your doctor to find the right dose.

  35. Scott Isaacs, MD says:
    Friday, June 21, 2013 at 11:21am

    I agree, work with your endo to find the perfect medication and dosage. I wish you the best.

  36. Dawn says:
    Monday, August 5, 2013 at 5:15am

    I’ve just had my tsh results from the receptionist who said 1.73 but but she could find no T3 or T4 results on the system. I have all the signs of hypothyroidism and have a family history what should I be asking my gp

  37. Mena says:
    Tuesday, August 13, 2013 at 1:19pm


    Thank you so much for this Article. I got a blood test done in July and was told by my physician that I had Borderline hypothyroidism with the result of 6.5. She prescribed me a low dose of 25 mcg Synthroid. As I started taking this, I started feeling extremely fatigue and hungry. i felt hungry all the time and kept eating a lot. I couldn’t do much around the house, I just wanted to sleep all the time. My eyes were turning red and my body felt like it was over heated. I thought I may be over medicated and maybe I should have waited and took another blood test before taking medications. Could my thyroid problem be a temporary alteration?


  38. Mena says:
    Tuesday, August 13, 2013 at 1:23pm

    Also, I went back to my physician and he said to stop taking the medication and get a blood test done after 3 months. After I stopped taking it, I feel so much better, active , and my appetite feels normal.

  39. Kellie says:
    Monday, August 19, 2013 at 8:42pm

    Hello, Dr Isaacs,

    I have a 14 yr old daughter who has TSH of 6.0.
    Free T3 and T4 were in the normal range
    This was discovered recently through a routine blood test when her annual physical was done.
    It was a complete surprise since she has no symptoms whatsover of hypothyroid.
    She is energetic and active, and seems perfectly healthy.

    We were then referred to pediatric endocrinologist who prescribed levothyroxine.

    We will soon be getting antibody tests done to make sure she does not have an autoimmune thyroid problem

    To me, it seems a rather aggressive treatment to medicate a child with a borderline hypothyroid after one blood test, especially since she has no symptoms at all.

    I’m really hesitant to medicate her until after further testing is done…Do you think I’m doing the right thing, or should I go ahead and start her on the meds

  40. Scott Isaacs, MD says:
    Wednesday, August 21, 2013 at 8:31am

    A TSH level of 6 can be normal in a 14 year old. The normal range for children (up to age 20) is different than adults.

  41. Scott Isaacs, MD says:
    Wednesday, August 21, 2013 at 8:32am

    Thyroid problems (both hypo and hyper) can be associated with eye problems. It is know as dysthyroid ophthalmopathy.

  42. Scott Isaacs, MD says:
    Wednesday, August 21, 2013 at 8:33am

    A TSH in that range is generally considered normal. I recommend a more detailed evaluation for your symptoms including full thyroid function tests and evaluation for other possible causes of your symptoms.

  43. Stephanie says:
    Thursday, August 29, 2013 at 9:08am

    Hello Dr Issacs,

    I have recently had a blood test which has shown a TSH of 4.88 and a Free T4 of 14.1. I have been struggling over the last year with weight gain that I can’t budge no matter how much exercise I do and a diet of 1400 calories a day. In addition I suffer from fatigue, brain fog and joint pain. I also have Lupus but this is well controlled and my recent tests for this are also within normal ranges at present and I haven’t had a flare for a couple of years.

    My doctor has said that my results are normal, but I really am struggling. Do you think I should request a second opinion?

    Thank you

  44. Valeria says:
    Saturday, September 7, 2013 at 6:47pm TSH came out 5.8 and my PC prescribe .25 Levothyroxine .Since I start taking the meds are feel tired and I got a joint pain,numbness in my legs and I don’t feel better at all.Shoul I just stop taking the meds?Please,any advice I will be very appreciate!thank you

  45. smita says:
    Tuesday, October 15, 2013 at 9:17pm

    I m 25 years married tsh level was 5.79 then my gp had given me 25 mcg tab I have taken d 25 mcg for 2 months now after 2 months my tsh level is 2.64 ..should I stop taking d tablets or should I take 12.5 mcg tab.

  46. jo says:
    Friday, October 18, 2013 at 3:04pm

    My TSH was 4.840 back in May when I had all my blood work done. Everything else was normal. I just got tested again yesterday and it’s 4.580. My Dr. wants to start me on low dose med. I’m not happy at all about having to take medication. I am 55 and have always been healthy and exercise regularly. I’m wondering if I should wait awhile before starting the med? I don’t think I have any symptoms but I’m menopausal so it’s hard to to determine if the fatigue and sometimes hot flashes are coming from that. Menopause messes with with so much! I guess my question is; do my TSH numbers seem high enough that I should start a medication?

  47. Jodie says:
    Monday, November 18, 2013 at 8:48am

    Last year I suffered a miscarriage and then I was diagnosed with hypothyroidism. My TSH was then at 15. I’m now 5 weeks pregnant and my recent tsh came back at 9.6, this goes up and down and the lowest it has been is 2.7 two months ago. About 30 mins after I eat I feel very sick and could eat again, is there a link between the thyroid function not working correctly and being pregnant? is this a dangerous sign my body is working overtime to cope with the pregnancy? Have an apt booked to see Endo next week.
    Any advice?

  48. Scott Isaacs, MD says:
    Tuesday, November 19, 2013 at 2:28pm

    There is a big link between miscarriages and hypothyroidism.

  49. Anne says:
    Monday, November 25, 2013 at 2:35pm

    I was in exactly the situation described here except I have fibromyalgia on top of everything else. It was all too easy to blame the fatigue and all the other symptoms of hypothyroidism on the fibromyalgia. For some reason my endocrinologist decided three months ago to put me on a very low dose of thyroid medication and the results have been next to miraculous. I still have the fibromyalgia symptoms but many of them have been GREATLY alleviated. I have much more energy – well, at least I can go out and walk the dog and do a bit of gardening which was much, much more than I could do for the past four years. It makes me wonder how many other people are suffering unnecessarily from hypothyroidism just because their test results didn’t quite fit the so-called “normal” parameters.

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