Borderline thyroid tests: When should you take thyroid medication?

January 27, 2011 87 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. Laura says:
    Tuesday, March 25, 2014 at 1:40pm

    I have had my TSH checked over the last 5 years as part of my physical it is everything from 4.80 – 7.6, they also looked at my T4 twice which was still in a normal range. My question is do you see variability in TSH level, seems like it is all over the place up and down in the range started above? I am 54 and post menopausal, having symptoms like fatigue, depression, brain fog, decreased libido, loss of words, but no issues with weight gain or constipation. I have however had an episode of GI reflux that has been challenging. Endoscopy is normal. My gyn wants me to try a low dose synthroid for my symptoms, and my pcp is more a retest some more. I am almost at the point where I need to take antidepressants. do you see this up and down with the TSH? Is this predicting that my thyroid is going to give out and I should just take the synthroid over a dose of an antidepressant. My symptoms are not terrible, just annoying and if I could feel better it would be nice!

  2. Scott Isaacs, MD says:
    Tuesday, August 19, 2014 at 7:51am

    I advise working with an endocrinologist. Your levels are borderline low and may need treatment. However, some people will normalize their thyroid levels without taking medications. It is a clinical decision you need to make with your doctor.

  3. Maureen Goldfuss says:
    Sunday, February 22, 2015 at 1:05pm

    My test results were T3=59; T4=3.7 ; TSH-3rd generation = 31.61;
    Back in 1991 I had radio active iodine because I had on interactive thyroid. Since then I have always taken synthroid. This last test shows that my thyroid is not at a normal range. I have been treated for Major Depression and I believe my thyroid has something to do with it.

  4. Debbie says:
    Monday, March 23, 2015 at 7:07pm

    I am 58, I’ve been on antidepressants 20 years, had em balanced hormones and many thyroid test. My Adrenal gland number was down to 2.9-3.01. I was on Cortisol for. One year. Always being in normal elevated numbers was frustrating. I haven’t been able to loose weight for 5 years even at 1400 calories. My waist size has increased and I feel terrible. On top of that I’ve waited 2 years for back surgery for disk fusion from SL 5 to the last L in the spine. I just want my life back. My new blood work showed my thyroid count at 6.66. I’m trying to find a new Endroconologist. Could this be the reason for extra weight, fatigue, and more depression?

  5. Leeanne Tyler-Olsen says:
    Wednesday, September 9, 2015 at 4:25am

    Hi Debbie,

    Just read you post. I am 59 & was diagnosed with Hashimoto’s 5 years ago. I’ve also been on antidepressants for 18 years & had fusion surgery & a disc replacement 31/2 years ago. We have a lot of similarities! I am now seeing a group of holistic doctors who recommended that I change my diet, which I have done. No gluten, soy, dairy or sugar. I am feeling much better than I was a year ago. I would recommend a book called: “Hashimoto’s Thyroiditis: Lifestyle Interventions for Finding & Treating the Root Cause” by Isabella Wentz. Isabella suffers from Hashimoto’s & has done a huge amount of research into the disease. Most GPs don’t have a clue about this & won’t know about the appropriate lifestyle interventions, nor how test results don’t give the full picture. If your results are “Euthyroid”, this doesn’t mean that there isn’t a problem. Hashimoto’s is a complex disease & is related to other autoimmune conditions, especially coeliac disease. Find yourself some really good doctors or a good endocrinologist who can sort things out for you. I hope you feel better soon! Best wishes, Leeanne from Oz.

  6. Jeff says:
    Saturday, November 21, 2015 at 1:27am

    TSH 7.6
    Triyodotironina TOTAL 67.5

    (T3 libre 2.4)

    Everything else normal. I generally feel like hell.

  7. Erica says:
    Tuesday, January 26, 2016 at 11:54am

    Once you start taking Armour Thyroid are you on it for life? I am borderline and was prescribed by a doctor other than my FP Doctor. My FO Doctor is mad I am on it and says if I take it for 6 months I will be on it for life because my thyroid will stop working because my Brady has the hormone from the pills.

  8. Scott Isaacs, MD says:
    Thursday, February 11, 2016 at 5:15pm

    If you really need it, it is for life. If you don’t need it you shouldn’t take it. I recommend that you see an endocrinologist who is familiar with The Endocrine Society Guidelines for the Management of Hypothyroidism.

  9. Amanda says:
    Monday, February 22, 2016 at 4:27pm

    for the past 4 months I have had irregular bleeding. A minimum of 2 menses per month. In January I had 3. My gyn ran varies tests on me from hormones to ultrasounds. She ran my tsh, which came back .329. She suggested my primary run some additional test on me related to the thyroid. My primary refused and referred me to an endocrinologist. Back in November my tsh was 2.7.

    to back track a little bit, I did receive interferon treatment in 2010. I did have SIGNIFICANT weight gain (60+ pounds), my hair continues to fall out in clumps, I have no energy ever to do anything, and if I could take frequent naps all day I would, on top of the extra menses.

    I saw an endocrinologist today. He did not seem very concerned with my tsh. He said it was “mild hyper” and would only consider putting me on methimazole once the blood tests he ran cam back, which is fine. The only hyper symptoms I have is heat sensitivity, most of my symptoms are hypo. He also stressed that even though my gyn ran every test she possibly could for my main concern and all was fine except tsh, that my issue is not an endocrine issue.

    I need some insight, or if should get a second opinion because I really can not take having this many menses.

  10. utsab das says:
    Tuesday, April 19, 2016 at 11:36am

    hello sir. im 30 yrs old. for past few yrs i feel very lethargic . my wait has gone up by 9kgs frm 90 to 99 in 2 yrs despite nt much lifestyle change. im doing good amt of exercise for last 3 months bt nt loosing much wt. i do annual or bi annual routine blood tests n check up. in 2013 my Tsh was 3.2 , in 2015 it was 4.78 , and today 19.6.2016 this year it has gone up to 5.22 . i have exams aftr few months n worried what should i do, will it affect my memory and perfrmnce, doctors are divided in opinion abt levothyroxine. one said no need. one said to start 25 levothyroxine od. im in dilemna abt what to do. pls suggest. thanks

  11. Scott Isaacs, MD says:
    Thursday, April 21, 2016 at 1:52pm

    You have some borderline tests, I recommend that you see an endocrinologist.

  12. Julie says:
    Thursday, June 30, 2016 at 5:08am

    tsh 5.76 t4 12.7 is this a definite hypothyroidism?

  13. Julie says:
    Thursday, June 30, 2016 at 5:24am

    Hi I have a TSH of 12.7 and T4 of 5.76 G.P advised me I have hypothyroidism very tired, feeling cold, sluggish and gained 2 stone in weight will this go away on its own or will it definitely need treatment ?(having a retest in 6 weeks)

  14. Elle says:
    Tuesday, August 9, 2016 at 2:20pm

    I recently went to a new endocrinologist because my family practice/alternative meds doc could not stabilize my thyroid in 4 years. I was placed on 50mg of levothyroxine and was on it for 5 weeks. The testing came back at TSH 3.510,Free T4 1.52 and T3 97. I have gained 2 pounds from this during this time. Do I really need this? Am I being overly medicated? Why am I gaining weight and unable to lose it, even though I am being extremely careful with my foods. It is so frustrating.

    Thank you

  15. Barbara says:
    Monday, September 26, 2016 at 9:30pm

    My internist wants to put me on thyroid medicine. Today’s blood result showed my TSH at 5.32 which is up from 4.9 a few months ago and 4.64 a few months before that. I am trying to avoid going on the medicine since you have to be on it for life I’m told..Is my number (the 5.32) at a point where I should start the medicine?

  16. Julia Velci says:
    Sunday, October 16, 2016 at 8:33pm

    Hi, I’m taking armour thyroid 60mg daily. My latest thyroid results are
    TSH 0.64 T3 uptake 39% T4 4 free thyroxine index 3.90. I have had insomnia for years, I went on armour thyroid for hair loss 4 years ago, it worked wonders, now I have brittle dry hair and hair loss, dry skin, I feel hot all the time and have an irregular heart beat. I am scheduled for mitral valve surgery on Nov 18th, so the irregular heartbeat could be due to my heart.

  17. Lisa says:
    Friday, October 21, 2016 at 8:45am

    In September I had half my thyroid removed. I just had blood work done and it shows that my TSH is 5.67 and my T4 is 11. What does this mean?

  18. Liza says:
    Wednesday, November 9, 2016 at 12:53pm

    I am 30, TSH- 5.79, T3 & T4 fall in normal range. Rise in TSH has been diagnosed for the first time. Please suggest, if I should wait for the next test or start with Thyronorm 25mcg?

  19. Prema says:
    Tuesday, February 14, 2017 at 11:08am

    I m 29 yrs old. My tsh report is 4.73 .Is it normal or high .Should I consult with doc.

  20. Scott Isaacs, M.D. says:
    Wednesday, February 15, 2017 at 10:01am

    Yes, see your doctor. This test needs to be repeated with additional testing.

  21. Scott Isaacs, M.D. says:
    Wednesday, February 15, 2017 at 10:02am

    It is always best to confirm an abnormal test with a second test before starting a lifelong medication.

  22. Scott Isaacs, M.D. says:
    Wednesday, February 15, 2017 at 10:07am

    I always support repeat testing, however a TSH of 12.7 is clearly abnormal.

  23. claire says:
    Sunday, March 5, 2017 at 8:52pm

    Hi, my tsh is 4.29. My doc prescribed me levothyroxin 25 mg daily for 2 months. I’m trying to conceive. What should I do?

  24. Blair says:
    Friday, March 10, 2017 at 3:38pm

    My daughter is 8 and the doctor told us that her thyroid level was .01 below the normal and wants to put her on Synthroid. The only reason she was even tested was because she has a small bald spot on the side of her head. Is it normal to be put on medication for just being .01 under normal?

  25. Scott Isaacs, M.D. says:
    Thursday, March 23, 2017 at 12:49pm

    There are several different thyroid labs. I am not sure which one you are referring to. Pediatric reference ranges for thyroid are different than adults.

  26. Scott Isaacs, M.D. says:
    Thursday, March 23, 2017 at 12:50pm

    There are guidelines for thyroid and pregnancy. Make sure you see a physician who is familiar with the guidelines.

  27. Vinay says:
    Tuesday, April 4, 2017 at 10:39am

    My TSH level is at 5.89. Am i need thyroid medication

  28. shla says:
    Sunday, April 16, 2017 at 5:36am

    I have just tested my TSH two months before, it was 6.1, my doctor advice me 12.5 mg thyroxin, I had some symptoms like feeling cold, constipation and recently gaining weight, after 6 weeks my TSH was 4.25 , so I am confuse to continue taking my medicine or tope it, I have done a lot search and its recommended to take the medicine in entire life, it look difficult for me, so anybody who has stopped taking the thyroxin can share his/her Experience , I should stopped it at once or gradually.

  29. Meg says:
    Sunday, April 30, 2017 at 10:24pm

    Hi Dr. Isaacs,

    I recently had an episode where it felt like my blood pressure dropped really low while standing, I lost all color, my lips started turning blue, my face felt cold, and I felt off-kilter and tired for days afterwards (they think I might have had a mild seizure of some sort). I went to Immediate Care a couple of days later and had blood tests run to see if I had Diabetes or was Anemic. I came back normal for those, but my TSH was 5.120 (I’m assuming this is only slightly higher than the normal end range of 4.5 for the lab my doctor uses). I went back to my primary care doctor on Friday who said I have a mild case of Hypothyroidism and prescribed 112 mcg Levothyroxine, told me to follow a Low FODMaP Diet for my severe IBS that I’ve had for years, to go Gluten/Dairy Free, and to come back in 6 weeks to make sure I’m on the right dosage of medication. Since starting the medication I haven’t had the cold sensation in my face any longer, but I’m curious as to why my doctor didn’t do a further blood test to check my T3 and T4. It seems everything I’ve read is that T3 and T4 is the best thyroid test for determining whether some really has thyroid issues. Perhaps she will check my T3 and T4 level in 6 weeks or do you think she will still just check the TSH range?

  30. Kiara says:
    Thursday, September 7, 2017 at 5:14am

    Hello Doctor,
    I am 28 years of age.
    My tsh was around 1.9 early this year, however few months ago we started trying to conceive so I did a routine check up and found out my tsh increased to 4.3. I went to an endocrinologist 4 days later and he did another test in which my results were as follows:
    TSH – 2.48
    free T3 – 4.38
    free T4 – 12.54
    Anti-Tg – 19.5
    Anti TPO – 691.4

    Since my tsh reduced the Endo said to just take selenium 200mcg as my anti tpo was high.

    That same very month I conceived and at 5 weeks I had a miscarriage.
    I am really worried if my mc was due to by tsh and anti tpo. I am very thin around 41kg and have no real signs of hypo.

    After my mc I did my tests again and my tsh was 4.6.

    Now my Endo says i should start taking a small dose of thyroxine.

    Please Help !!!!

  31. Michelle says:
    Thursday, November 2, 2017 at 8:16pm

    Gaining weight, sleeping all the time, like bone tired. I was on rituxan
    For two yrs. tosh is 3.678? Is this a thyroid problem?

  32. Edna Fugate says:
    Monday, November 6, 2017 at 1:33pm

    Should I listen to my 2 doctors who tell me 7 is OK for TSH? My dtr. took thyroid meds when here was 4. I am in chronic A-Fib and when I went to the hospital last yr. with chest pain, they said I could stop my chronic A-Fib by taking thyroid meds which my cardiologist agreed but my Internist (not another one since he retired), does not want to give me thyroid meds as they think it can damage my heart so who am to believe when doctors do not agree?

  33. Jean says:
    Friday, November 17, 2017 at 1:10am

    My TSA level is 1.3. I am 67 years old. Is this a normal number?

  34. Priya says:
    Saturday, December 16, 2017 at 2:37am

    I am on thyroxine 50 recent tsh level is 3.2, t3 17, t4 4.7..still to continue 50 or to increase? Is ovulation possible with this range..I am 30 now and trying to conceive..

  35. Lara says:
    Thursday, February 1, 2018 at 9:29pm

    My thyroid is normal should I still take my medicine?

  36. Stace says:
    Tuesday, March 27, 2018 at 10:44am

    I am 42, feeling very tired all the time and hard time falling alseep at night, hard time concentrating. Went to the doctors TSH was 4.7 but doctor said it was normal. Looked at past TSH levels all 2.0-2.8. My mom and aunt both have thyroid problems and had to be removed, mom cancer. Should I go see a different doctor?

  37. Estelle Richardson says:
    Thursday, June 7, 2018 at 12:31pm

    Hi I’ve been on 25mg levothyroxine for a good 5 years I had my yearly blood test for thyroid which came back boarderline but the doctor automatically doubled my dose to 50mg 3 weeks ago since then I’ve have palpitations, feel very aggravated and generally unwell could it be to higher dose?


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