Optimal vs Normal Thyroid Levels for All Lab Tests & Ages

Optimal vs Normal Thyroid Levels for All Lab Tests & Ages

Do you have the feeling that your thyroid hormones may not be optimal even though they are normal?

Does it make sense to you that each person might have a different optimal level? 

Or that maybe your genetics are playing a role in your thyroid function?

If you answered yes then this article is for you!

In it we will explore the idea of "normal thyroid levels" and "optimal thyroid levels" and how using the latter may help you feel better and reduce your symptoms. 

Let's jump in: 


The Difference Between "Optimal" and "Normal"

Thyroid hormones, like other hormones in the body, exist on a spectrum. 

What this means is that your thyroid levels are not "black and white". 

The amount of thyroid hormone that you need differs from the amount of thyroid hormone that someone else needs. 

So why do Doctors insist on following the reference ranges given by labs?

To understand this you must understand how labs create these reference ranges. 

Reference ranges represent values based on standard deviations of the local population (1). 

This is also the reason that each lab has different values for their tests!

The actual lab values differ among populations, locations, and ethnicities. 

So how can we take something so complex and boil it down to simple reference range endocrinology?

The practice of medicine that is relegated to numbers rather than symptoms and the clinical picture of the patient?

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Part of the reason has to do with how complex it would be to find the "perfect" dose for each patient, but just because it's difficult doesn't mean it shouldn't be attempted. 

Because of the way that lab values are created we have a situation in which there are two ways to look at thyroid hormone in the serum (this applies to all hormones). 

The first is to compare your specific values to that of the standard reference range

In this approach, you are simply looking at the value of your thyroid lab tests and determining if they fall within the large range provided. 

If you fall within the range then you are considered "good" and no more treatment is required. 

This practice is known as reference range endocrinology and is a way to standardize hormone therapy. 

This is also the same approach that MOST Doctors use when analyzing hormone levels and thyroid levels. 

A second approach, and perhaps a better approach for many people, is to look at the value within the reference range and compare this value to the clinical picture of the patient

If the value is in the low end of the reference range then perhaps it's worth considering that even though the value is technically normal that it may not be normal for that person, especially in the face of abnormal symptoms. 

Consider this example:

Testosterone tends to peak in men in their teens and then slowly decline over time (2).

This gradual decline (which occurs with many hormones) should change how Doctors look at the testosterone levels based on the age of the patient. 

A 50-year-old man should (and will) have different testosterone levels than a 20-year-old man. 

You would think that this would be obvious, but the reference range is the same for ALL men older than 18 and up into their 80's. 

So, using this approach, a Testosterone level of 200 in a 50-year-old is no more concerning than a testosterone level of 200 in a 20-year-old because technically they both fall within the "normal range". 

Obviously, the testosterone level of 200 is MORE concerning to the younger patient because this is a time when testosterone should be near the PEAK

The bottom line?

Using a combination of age AND the clinical picture will allow for tighter control of hormone replacement therapy. 

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This same logic should apply when evaluating and treating thyroid dysfunction. 

By altering the way that we look at the absolute values of thyroid hormones we can create a "normal range" but also an "optimal range". 

This optimal range represents the ideal range that would be seen in an active, healthy adult without any medical conditions or metabolic issues

And this is the range that you want to aim for - not the generic range created through statistical analysis of the population surrounding you. 

The optimal range isn't perfect, but it will allow you to better understand why you may not feel well despite having so-called "normal" thyroid lab tests. 

If you are symptomatic (meaning you have fatigue, weight gain, cold intolerance and so on) then you should compare your actual lab tests to the "optimal ranges" provided below

Complete Lab Test

Abbreviation (Commonly referred to as)

Normal Range (Reference range on labs)

Optimal Range (Based on healthy adults)

Thyroid stimulating hormone


0.450 - 4.500 uIU/mL

0.5 - 1.0 uIU/mL

Free T3, Triiodothyronine


2.0 - 4.4 pg/mL

3.8 - 4.4 pg/mL

Free T4, Thyroxine


0.82 - 1.77 ng/dL

1.4 - 1.77 ng/dL

Reverse T3, Reverse Triiodothyronine


9.2 - 24.1 ng/dL

Less than 15.0 ng/dL

Total T3, Total Triiodothyronine


71 - 180 ng/dL

150 - 180 ng/dL

Thyroglobulin Antibody


0.0 - 0.9 IU/mL

0.0 IU/mL

Thyroid Peroxidase Antibody


0 - 34 IU/mL

0.0 IU/mL

Note that each lab test has slightly different reference ranges but you can use the optimal ranges above to give you an idea that you can then apply to other lab companies and their reference ranges. 

The reference ranges and units listed above are generated from LabCorp which is a lab testing company common in the United States

If you compare your lab results to the reference range vs the optimal range you will notice that the optimal range is really just a "tighter" version of the reference range. 

The standard reference range is much larger and it has to be to encompass a wide variety of ages that are used when it is created. 

Thyroid Lab Tests Available

Beyond simply using the table above to compare your results to, it's often better to actually understand what is being tested and what it means in a larger sense. 

Understanding what thyroid lab tests mean will help you understand what tests you 

This is important because many physicians will not order a complete thyroid lab panel and instead will focus only on 1-2 standard tests.

Ordering a more expansive panel is often better, at least initially, because it can help identify common patterns of thyroid disease seen in various conditions. 

Some conditions, such as obesity, cause only slight dysfunction in thyroid hormone which can be missed unless certain tests such as Reverse T3 are ordered. 

Other conditions, such as Hashimoto's thyroiditis, may be missed if thyroid antibodies are not ordered. 

Because of this, you should also have a basic understanding of the most common patterns of thyroid disease, some of which are outlined below: 

Disease Condition



Thyroid Antibodies (TPOab & TGab)

Reverse T3


High (greater than 2.0)

Low (usually bottom 20-30% of the reference range)



Hashimoto's Thyroiditis

May fluctuate over time but often normal

Low (usually bottom 20-30% of the reference range)



Graves' Disease

Low (very close to 0)

T3 is high, FT4 may be low

Normal (TSI may be elevated (3))

Low to Normal




High (usually higher than 20.0)



Low to Normal



This table doesn't include ALL patterns, but it should work to give you a general idea of how to evaluate thyroid lab tests. 

With this table in mind let's discuss what each lab test means: 

  • TSH - TSH tests pituitary function and can be used to diagnose thyroid disease. 
  • Free T3 - Free T3 may be the most important measure of thyroid function in the serum because it measures the free and active thyroid hormone. T3 is more biologically active than T4. 
  • Free T4 - Free T4 measures the amount of free T4 in circulation. In order to be activated, T4 must turn into T3 so T4. 
  • Total T3 - Total T3 includes measurement of bound T3. Bound T3 is not considered active like free T3 but total T3 gives you a more stable long-term marker of T3 in circulation. 
  • Thyroid Antibodies - The thyroid antibodies include thyroglobulin antibody, thyroid peroxidase antibody and thyroid stimulating immunoglobulin. The presence of these antibodies in your serum may indicate an autoimmune disease which is damaging your thyroid gland. 
  • Reverse T3 - Reverse T3 helps measure the conversion capacity of your thyroid gland. High reverse T3 may be a sign that your body is having trouble converting T4 into the active thyroid hormone T3. High reverse T3 is commonly seen after rapid weight loss, in obesity, and in euthyroid sick syndrome (5).

You can learn more about each test in the links above. 

Understanding TSH and the Controversy Surrounding this Test

TSH stands for Thyroid Stimulating Hormone and may be the most common thyroid test ordered. 

TSH is a measure of pituitary function which is a gland in the brain. 

Under normal circumstances, your body produces TSH which then tells the thyroid gland to produce thyroid hormone. 

A high TSH is often a sign of hypothyroidism or inactive thyroid gland function while a low TSH is often a sign of hyperthyroidism or excessive thyroid gland function. 

This can be confusing because intuitively it would seem that if there is a high amount of TSH being produced that there would also be a high amount of thyroid hormone being produced. 

After all, TSH does have the name STIMULATING in it!

But this isn't the case because in order for TSH to be effective the thyroid gland must be working. 

So even if TSH is high, if the thyroid gland can't produce thyroid hormone (because of inflammation or damage) and therefore thyroid hormone production will be impaired. 

If this is confusing to you, don't worry!

You can just stick to the table above or look at the optimal ranges to help you understand if your TSH is in the right place. 

TSH is often very helpful during the initial diagnosis of thyroid disease but tends to lack value after starting medication. 

The reason for this has to do with how important free thyroid hormone levels for managing symptoms. 

A so-called normal TSH ranges from 0.45 to 4.5 but newer studies have emerged which suggest a tighter range is likely necessary (6).

This newer range indicates that any TSH over 2.0-2.5 is likely abnormal and an early sign of thyroid disease (7).

When you are being treated with thyroid hormone a TSH of 0.5 to 1.0 is probably the ideal goal to shoot for as it more closely mimics the range of healthy adults (8).

Thyroid Testing by Age & Other Factors

Optimal lab ranges may vary based on metabolic capacity, thyroid conversion and the genetics of the individual. 

Compared to other hormones in the body it looks like thyroid hormone is one hormone that really shouldn't diminish with age. 

What do I mean?

I mean that healthy older adults (70+) still show normal TSH and free thyroid hormones when compared to younger adults (9).

This is actually uncommon when compared to other hormones such as estrogen/progesterone in women and testosterone in men (both which show a dramatic decline as we age). 

Part of the reason that thyroid hormone may be preserved overage is that of its importance in metabolic function and determining the metabolism of the body. 

Even though thyroid hormones shouldn't decline with age we do see a general increase in the incidence and risk of thyroid disease in people as they age (10).

This means that you have a much higher risk of developing thyroid disease (including hypothyroidism, hyperthyroidism and thyroid cancer) the older you get. 

We also know that older individuals tend to become more sensitive to thyroid hormone medications. 

This can create a tricky situation in which replacing thyroid hormone is necessary, but it can be difficult due to symptoms that may occur with this therapy. 

Even though it's difficult it's still very important to maintain normal thyroid hormone levels throughout your life!

In fact, this approach to treatment is considered to fall into the category of "anti-aging" because the whole goal is to return hormonal levels to a more youthful pattern. 

Thyroid hormone, much like the other sex hormones, plays a critical role in the regulation of important factors such as metabolism and body weight. 

It may be that the inability to diagnose and treat thyroid issues may cause a pathological physiologic change that results in premature signs of aging (11).

For this reason, it's important to properly identify and treat thyroid disease regardless of your age. 

Bottom Line: "Optimal" thyroid hormone levels do not change with age, but as you age you may be at higher risk of developing thyroid problems. This should be compared to other sex hormones which do decline with age. 

Thyroid Lab Tests During Pregnancy

Another physiologic condition which may alter the new "normal" when it comes to thyroid lab tests is pregnancy (12).

During pregnancy, the best marker of thyroid status may be the measurement of free thyroid hormones such as Free T3 and Free T4. 

TSH becomes less helpful because the placenta secretes hormones such as human chorionic gonadotropin, chorionic thyrotrophin, and molar thyrotrophin (13).

Pregnant and lactating women have an increased demand for thyroid function in the body. 

This demand extends to certain nutrients, especially iodine (14).

During fetal development, the thyroid gland from the fetus takes up and produces thyroid hormone which is critical for normal development. 

This means that proper iodine intake is required for pregnant women due to this increased demand!

This also means if you are pregnant and taking thyroid medication you may need to have your dose adjusted. 

When you are taking thyroid medication, prior to pregnancy, your body may become dependent on the dose of thyroid medication that you are currently taking. 

When this occurs your body is incapable of producing thyroid hormone naturally. 

This means that your body can't naturally increase the amount of thyroid hormone that your body needs once you become pregnant. 

Because of this, you need to have your thyroid dose adjusted as SOON as you become pregnant. 

On average thyroid hormone doses need to be increased anywhere from 40% to 100% during pregnancy (and depending on the trimester) (15).

So if you were taking 50mcg of Synthroid prior to pregnancy, you may need up to 100mcg of Synthroid while you are actively pregnant. 

It's also worth pointing out that thyroid lab tests become less valuable during pregnancy as well. 

Due to changes in thyroid hormone activity the standard and even "optimal" reference ranges become less helpful. 

Because of this, you will need to pay close attention to your symptoms during pregnancy and monitor closely for the signs and symptoms of hypothyroidism during this critical time

Symptoms such as rapid weight gain, crushing fatigue, hair loss, constipation and so on may be early indicators that you are getting insufficient thyroid hormone. 

Final Thoughts

When it comes to hormones it's often best to consider "optimal ranges" as opposed to "normal" ranges. 

The reason for this is that each person has differing baseline hormone levels which means that the dose and optimal range for you will be different than other individuals. 

If you are undergoing thyroid hormone replacement therapy you will often find superior results (as evidenced by more weight loss and reduced symptoms) when you take this approach. 

In addition, watch out for other physiologic conditions that may alter the amount of thyroid hormone that your body needs!

Highly stressful situations, age and even pregnancy may all alter these references ranges and may alter the amount of thyroid hormone that you need day to day. 

Now I want to hear from you:

Do you understand the difference between normal and optimal?

Are you having trouble getting your levels into the perfect range?

Do you have a doctor willing to work with you?

Leave your comments below!

References (Click to Expand)

updated optimal thyroid lab tests
Dr. Westin Childs

Dr. Westin Childs is a Doctor of Osteopathic Medicine. He provides well-researched actionable information about hormone-related disorders and formulates supplements to treat these disorders. He is trained in Internal Medicine, Functional Medicine, and Integrative Medicine. His focus is on managing thyroid disorders, weight loss resistance, and other sex hormone imbalances. You can read more about his own personal journey here.

54 thoughts on “Optimal vs Normal Thyroid Levels for All Lab Tests & Ages”

  1. I had been experiencing various symptoms of hypothyroidism for the last 2-3 years but kept writing them off. It wasn’t until I noticed a larger bump on my thyroid gland and had difficulty swallowing that I saw the endocrinologist. My nodule was large enough that they performed an ultrasound and biopsied and at this time everything looks ok and we will be monitored yearly. I also have low basal body temp and below average resting heart rate (less than 50-55bpm on average).

    My most recent labs are (although due to a lab slip error my Reverse T3 and Antibodies were done 2 weeks after the rest of my labs).

    TSH – 3.14
    Free T3 – 2.9
    Free T4 – 1
    Reverse T3 – 9
    TPOab – 1
    TgaB – 1
    Vit D – 25

    Because I am still symptomatic, my doctor has now recommended a trial of 12.5 mg Synthroid to start. Does this sound like the best path forward – should I be considering other medications? I’m nervous about using medication but I am also at my wit’s end and want to feel better.

    • Hi Kristin,

      The choice to start medication largely depends on the goals of the patient, the underlying cause of the symptoms and whether or not you think it can’t be solved with other natural therapies first. I don’t have enough information to say one way or the other.

    • I was getting heart palpitations, weight loss, etc. and TSH was .37. Other labs showed TSH at 1.0 but I still had palpitations. I had these symptoms 6 years ago as well and TSH was .32.
      My most recent labs (April) show TSH at .5 I am on propranol for palpitations but endocrinologist said no need for thyroid meds because my TSH is now .5 I am very confused. Should I be treated for hyperthyroidism or not?

      • Hi Sharon,

        It looks like your body is trying to push towards hyperthyroidism but you aren’t quite all the way there by standard definitions. But propranolol is a treatment for hyperthyroidism, so I would say you are ‘kinda’ being treated for it already. That or your current doctor thinks your palpitations are completely unrelated to your TSH (which could also be true).

    • Hi Kristin,

      A very helpful article. I’m curious how you determine the optimal ranges? Do Lap Corp / Quest Diagnostics provide these ranges as well as the normal range? Or are these taken from our population studies?

      Many thanks!

      • Hi Ben,

        The optimal ranges here are based on my own experience and the experience of others. The absolute range isn’t as important as the concept that there is a difference between optimal and normal.

  2. Your thoughts on the following LabCorp results, please.
    TSH -0.006 (my doc is freaking)
    RT3-20.4 ( I think it’s high)
    I’m taking 75mcg Levothyroxine/15mcg Liothyronine compounded, with another 10 mcg Liothyronine for later in the day consumption. I still itch and my feet hurt.
    I’m 53, have IR, High A1c, and Beta Cell dysfunction! ( yay me!!)
    But doing low carb/high fat to help with that part. Thanks for any input!

  3. Hello Dr. Childs,

    I’ve been taking Levoxyl since 2009. On 4/30/18 I asked my MD to do more Thyroid tests because I was still not feeling well and thought my T3 was too low. She only tested TSH, Free T3, and Total T3. She did agree that my T3 was low so she prescribed 5mcg Liothyronine in addition to the 100mcg Levoxyl I was already taking. I retested on 6/27/18 and my current results are below. My MD says that I am over-medicated now. Can you tell by the results below or would I need more testing? I’d love to find a good MD or Functional Doctor who would be more willing to try different tests!

    TSH: 2/3/17 (1.07), 4/30/18 (1.07), 6/27/18 (.28)
    T3 Free: 3/19/15 (4.1), 4/30/18 (1.8), 6/27/18 (2.5)
    Total T3: 4/30/18 (76), 6/27/18 (102)

    Any guidance you can provide me with would be greatly appreciated!

    Thank you,

    • Hi Patrice,

      I would recommend that you start with a complete thyroid lab panel and sex hormone testing to help guide treatment.

  4. Hi Dr. Childs,

    Thank you so much for creating such a meaningful website!

    I’m 19 weeks pregnant and my levels are not optimal even after increasing the dosage of Synthoid twice during my pregnancy (esp. T3 levels). I’m currently on 88 mcg.

    TSH: 1.2(week 5) 2.8(week 14) 0.39 (week 19). (ref: 0.45-4.5)
    FT4: 1.0(week 5) 0.9(week 14) 1.25 (week 19). (ref: 0.82 -1.77)
    FT3: 2.7(week 14) 2.40(week 19). (ref: 2.0-4.4)
    TT3: 82( week 14)
    Reverse T3: 20.8 (week 14)
    TpoAntibody 313 (prior to pregnancy) 124(week 14)
    Iron: 88 (ref: 27-157)
    Ferritin: 39 (ref: 15-150)
    UIBC: 248 ( ref: 131 -425)
    Iron saturation : 26%
    Vitamin D3: 39 (ref 30-100)
    Vitamine B12: 762

    Are those levels bad? Do you think adding T3 into my current medication is appropriate during pregnancy? It’s so hard to find a doctor in the bay area who can prescribe T3 to pregnant woman. Any advice will be highly appreciated!


  5. Hi doctor, today I got my lab results and found out that my ft3 was 2,1 and I would like to know if taking cytomel along with levothyroxine would help me raise it at least to 3.5 I feel pretty much low and tired most of the time. I am already on levothyroxine 75 mcg. Could you suggest me how much of t3 I would need to take to get there please? Last time I checked my tsh was 1.98. Thank you!

    • Hi SZD,

      Unfortunately, I can’t provide medical advice through this website but you can find a local doctor to help titrate and adjust your medication! Hope this helps.

  6. I am so sorry for the awful question-but how do you figure out the bottom 20%-30% of a reference range? My calculations left me below the lowest number.
    Thank you in afvance for a math lesson.

  7. Hello Dr. Childs,
    I would like to hear your opinion what I could do to help my thyroid function in a natural way.
    I’ve been feeling typical symptoms of hypothyroid (lower than normal energy, often times feeling cold, recently gained ~7 pounds, etc.). Only recently looked into testing it because in addition to those symptoms I haven’t had a period for the last year (I am 38 years old and not in menopause). I was previously on birth control pills for 7 straight years, now stopped taking them for a little bit over a year.
    Test results:
    TSH 2.45
    Free T4 0.97
    Free T3 1.8
    Total T4 5.47
    Total T3 55.2
    Anti-TPO 9.2
    Reverse T3 11
    Vitamin D 41.2
    Vitamin B12 1314
    My cholesterol panel and hemoglobin is very good.
    I eat very clean diet (lots of vegetables, limited amount of fruits, wild seafood, eggs, legumes, raw nuts & seeds, haven’t eaten meat in 10 years, recently started avoiding dairy/gluten/sugar/soy (occasionally will eat tempeh/miso), try to eat mostly organic foods.

    My doctor does not think I have Hashimoto’s. I do not want to take any synthetic drugs, and my doctor did not recommend them yet. The doctor suggested taking Thyroid Synergy supplement for the next 2 months to see if it will help.

    Should I be concerned about my test results? What could I do to improve them?

    Thank you in advance for your input.

  8. Dear Dr. Childs

    I was diagnosed with Hashimoto’s thyroiditis in 2016. Lots of hypothyroid symptoms. Referred to another doctor because she would not give me thyroid meds, got on thyroid meds again.

    Thyroid meds
    Sept. 2017. 15mg, then 30mg then, 65mg. Armour (Tetzlaff)
    January 2018 increased to 81.25 switched to Nature throid (Childs)
    July 2018 increased to 97.5 (Trotter)

    Thyroglobulin TPO
    June 2017 2200 985
    Jan 2018 1000 900
    July 2018 2250 460

    TSH – (climbing up from extremely low in Jan and July 2018)

    Feb 2015 .08 (taken off thyroid meds)
    Aug 2015 .02
    Sept 2016 <0.015 (initial report said no result and redone)
    June 2017 <0.015
    Sept 2017 <0.015 (started on 15mg to 30mg to 65mg Armour)
    Jan 2018 .01 (up to 81.25 Nature thyroid from here)
    July 2018 .02 (up to 97.5 Nature throid from here)

    Reverse T3 (lowering in July 2018)
    June 2017 23.1
    January 2018 25
    July 2018 17.7

    I have had symptom relief, generally the worst symptoms are diminishing greatly. (malaise, hives, more alive now) I still have many hypothyroid symptoms. I believe I need to be on T3, although the RT3 is lowering.

    Since the RT3 is lowering and the antibodies are starting to lower would you suggest T3 with Nature throid, or would you say I am starting to convert T4 to T3?

    I do know this is very complicated but I thought you might have a comment on whether it seems that I am converting T4 to T3 now.

    Thank you, Dhyanna Goulet

  9. I have had symptoms of hypothyroidism for years. My family history is full of autoimmune issues and my mother had thyroid cancer in her early 30s. I am currently 38. I have finally convinced my doc to treat based on my symptoms after my lab work in May. Here are my lab results:

    TSH – 1.76
    FT4 – 1.15
    FT3 – 2.84

    TSH – 0.84
    FT4 – 1.32
    FT3 – 2.90
    TT3 – 90

    I was then started on a super low dose of Armour thyroid. I think it was on only 7.5 mg for 4 weeks and then up to 15 mg.

    TSH – 1.70
    FT4 – 1.10
    FT3 – 3.16

    My dose was increased to 30 mg. I still don’t feel fabulous on most days. I feel like I felt a small bit of difference every time I first started increased dose and then back to yucky. I do have a small nodule in the middle of my thyroid that doc wants to check again in October. I know that you can’t offer medical advice, but does it seem like I am on the right track? I will be talking to my doc about increasing my dose of the Armour.

    • Hi Jennifer,

      If you are feeling an improvement and your lab tests are showing an improvement then it sounds like you may be on the right track.

  10. I have been curious as to whether my son’s ADHD behavior (he is not on any medication) and other symptoms are thyroid related and so I recently had him tested. His symptoms: has a VERY hard time focusing, low energy, very skinny despite eating a lot, high anxiety, very very dry skin, high heart rate, runs warm, sleep issues…he’s also sick frequently.

    Here were his results:
    TSH 1.83
    Free T3 5.00
    Free T4 1.01
    TPO 10

    His doctor of course said he is normal and that is that. I don’t like that his Free T3 is so high. I also don’t like that his antibodies are elevated at all. I feel his body is giving warning signs and I want to turn it around now. I am at a loss, though. I don’t know who to turn to and find very little information that is helpful for A) kids and thyroid, B) hyper thyroid that is not full blown Graves.

    Can you point me in a good direction? I would really love to turn this around for my kiddo and am actually happy to have found some kind of a connection with a root cause. Now, the what to do about it part…

    Thanks so much, I really value your work!
    Jessica Parker

  11. Do you have reference ranges for 12 year olds? We’ve been following my daughter due to my history with hashimotos, my thyroid cancer and her symptoms. Her tsh has climbed to 4.7 which is still “in range”. She has hashimotos, is celiac and has a newly diagnosed autoimmune disease. I can’t seem to find any charts for kids tsh, ft3, ft4, etc. Thank you.

  12. Interested in your thoughts on these lab results:

    T3 free – 2.7 (2.3-4.2)
    t4free – .65 (.77 – 1.61)
    TSH 2.62 (.34-4.82)

    night sweats
    dry skin
    hard time losing weight
    anxiety/mood swings

  13. Hi there, i was diagnosed with Hasimotos when i was 28, i am now 58. I was Eltroxin 150mcg for many years, always felt tired! In my 40’s dose reduced to 125mcg as i was going overactive. This seems to be when all my struggles came about, more tired, weight gain of about 20lbs..brain fog. I just came to the conclusion that i was just getting older. After many talks with my MD she decided to leave me on 50mcg Eltroxin and 30mcg Natural desiccated thyroid. At the beginning i felt awesome for a couple of months then right back to being so tired. The doc asked if i wanted to go on just desicatted. I said sure! The labwork in Early January 2019 were the following TSH 5.32 Reference are in Canada is 0.32-4.00
    T4 13- Reference range 9-19
    T3 3.0-Referance range 2.6-5.8
    Doc put me on 60mcg of Thyroid only…will be getting lab work done again mid Febuary. What are your thoughts on my T3 Levels?
    Thank you,
    Kari From Canada

  14. CRAZY CHANGE – I’ve been on Armor thyroid for about 40 years. My tests always vary and the doctor makes small adjustments. Since my last test my TSH HAS JUMPED UP TO 69.07 H! I can’t imagine it could go that high. I’m interested in what could make such a Monumental jump in 6 months. My T4 free is .5L and my T3 is 2.4.
    Obviously something wild is going on. I did go through a huge stress about a month ago, possibly a TIA.
    Any idea what could cause this?

    • Hi Jamie,

      I don’t think anything wild is going on necessarily. Stuff like this happens frequently if you treat enough patients. It could be something as easy as a lab error or the fact that your body now needs more thyroid hormone than it used to. The demand for thyroid hormone in the body changes on a daily basis so it’s not uncommon for that demand to increase or decrease over time. It’s never the case that you can sit at the same dose of thyroid hormone for years and years.

  15. Hi Dr. Childs. Thank you for all of the helpful information that you provide on this site. I have a quick question. I have had my thyroid levels tested twice recently, and the results were dramatically different. The first test (done online through a company called Modern Fertility) said that my TSH was 6.43, and my FT4 was 0.77. The second test (done 2 weeks later through my doctor’s office) said that my TSH was 2.9, and my FT4 was 0.99. Is it possible for TSH to change so dramatically in such a short amount of time? My doctor has concluded that my thyroid is fine and nothing needs to be done, but I am concerned because I had a miscarriage last summer, and we’ve been unable to conceive again since then. I suspect that my thyroid my be preventing us from getting pregnant and/or increasing our risk of having another miscarriage. Should I get another test done? Should I find a new doctor? Any advice you could offer would be greatly appreciated.Thank you!

  16. Hi Dr, Childs,

    I am a 45-year-old female with a family history of Hashimoto’s and hypothyroidism. I am suffering from hair loss, aching joints but I also suffer from fibromyalgia, almost always cold, suffer severely when it is cold, suffer from migraines, heart palpitations, and exhaustion/sleepiness to name a few symptoms. My doctor felt it was only necessary to run a TSH and iron test. My TSH level was 2.7 so he ruled out my thyroid and anemia and said I was suffering was women’s hair loss. My body is telling me something different. Do you think I should have further testing or get a second opinion and do you feel it could be thyroid related? Any advice is greatly appreciated. I am worried about my health and that I am going to go bald by the time this is figured out.

  17. Dr.Childs,

    I am 62 and have been experiencing hair loss/thinning hair for the last two years. It seems to have started when I was taking HRT (testosterone) and my testo levels were extremely elevated. Then I had thyroid surgery (removal of right thyroid). So both the doctors (dermatologist and endocrinologist) attributed it to these factors. Fortunately after 6 months my hair loss slowed down considerably. Now it has began again and all of my lab results are in the normal ranges. But after reading your article I am wondering if that normal is not normal for me. Therefore, I would appreciate your expertise regarding any of these lab results that I should question/focus on more closely that could be a cause for or contributing factor to my hair loss.

    Thank you so much,

  18. Thank you for this post – SO HELPFUL!! My two teenagers (1 son and 1 daughter) began showing hypo symptoms in their teen years (hair loss, weight gain). Their extended thyroid lab panels show markers outside the optimal range (but no Hashimoto’s). Is this common and will they likely require lifelong treatment or could fluctuating hormone levels common in the teen years regulate themselves with age?

    • Hi Kellye,

      I do find that teenagers, in particular, seem to be sensitive to stress which can impact their thyroid markers. It’s impossible to say if that is what is happening in this case, but just because they have some abnormalities doesn’t necessarily indicate that they need to be medicated. Instead, it may mean that they need to look at other factors such as stress, etc.

  19. Dear Dr. Childs,

    I have Hashimoto thyroiditis since around 15 years.

    I used to take 125 µg of Thyroxine for this and it went fine until I stopped with the contraceptive pill and my TSH went down from 1.4 to 0.13 within 1 month.

    Because of that my dose was reduced to 100 µg Tirosint and yesterday my lab values were:

    TSH – 1.38 uIU/mL
    FT4 – 1.22 ng/dL
    T3 – 71.6 ng/dL

    Unfortunately my doctor refuses to measure FT3 and RT3.

    Can one conclude from the low T3 value that I would benefit from a T4/T3 combination therapy?

    Best regards,


    • Hi Leonie,

      I wouldn’t make that assertion based off of those lab tests (they are incomplete), but it still could be possible that you would benefit from it. You might be able to get by with T4 + additional supplements or T4 + lifestyle changes, etc. There are ways to force the T3 up without taking T3 medication but without more info, it’s hard to say.

  20. Hi Dr. Childs,
    I’m so glad I came across this site. I have been to dozens and dozens of doctors, have been tested for everything under the sun, no one seems to pay attention to anything but the labs. I have been struggling with symptoms for years, the most bothersome being weight loss with the inability to gain no matter what I do and hair loss and thinning on head and body. Hair is very dry. As I age, fatigue and more aches and pains become part of the mix. Every doctor I see says it sounds like my thyroid but when they run labs, all is normal. Hyperthyroidism runs heavily on my maternal side. I know you can’t diagnose but could I have a thyroid issue with normal labs? I don’t know what to do, every day is a struggle. I just want to feel normal – I’m 40 but feel much older. Any advice is appreciated. Thank you for your time.

  21. Hair starting to fall again and leg cramps and tingling in calves.
    And thigh muscles lots of stiffness in the spine. Upped magnesium and trying to get more potassium and water.
    New labs Doctor only does tsh 1.80,t4 .8, t3 2.55.
    Test done with no nature throid first thing in the morning, I think I need more thyroid hormone but my dr says normal range. What are your thoughts?

  22. I am a 72 y/o female. I have been on levothyroxin a huge part of my life. It has been a “higher than normal” dosage according to every doctor I have seen but had been stable for many years until this NP I am currently seeing. Without testing at all & without asking me any questions at all she withheld & then substantially reduced my dosage. This threw me into major symptoms including heart issues as well as all the typical hypothyroid symptoms.
    My tests rarely reflect the clinical symptoms. My test show I am low-below the range for normal. However when the dosage is reduced-as I am going thru now I am not just uncomfortable but in danger. The previous doctors & endos understood I am not normal & we did well until now. All the professionals I am dealing with agree that my dosage needs to be restored but the NP refuses to consider any thing other that her decision based only on the tests-even tho my health is deteriorating rapidly. Do you have any suggestions that might help, please?

  23. Hello. I live near Richmond, VA and am looking for an MD who will work closely with me on Hashi’s and menopause. I’m working with my PCP, and he thinks my levels are “normal” on my current treatments, but I’m still symptomatic in many ways. Any recommendations on a type of MD or a means of finding one? Thank you so much in advance.

  24. Hi Dr Childs,

    First of all, I want to thank you for posting such detailed information about thyroid problems. I was diagnosed 5 years ago with hypothyroidism. I was put on Synthroid for the first year and although my TSH levels returned to normal none of my symptoms went away. My internist allowed me to try Armour Thyroid upon my request which worked wonderfully until recently. I went back to my internist complaining of major hypothyroid symptoms and feeling just plain awful. He tested my TSH and it came back 0.5. He then ran an ANA test which came back positive. He has refused to check my Free T3 and Free T4 levels saying that he only uses the TSH to treat patients. Because of this, I went to see the local nurse practitioner that my children see in my home town. I requested that he run a full thyroid panel and these were my results. The nurse practitioner doesn’t recommend increasing my medicine even though my FT3 and FT4 were both low. I have an appt with an endecrinologist but it is not until February. Why would my TSH levels read normal but my thyroid hormones be low? Is this common with Hashimoto’s or Thyroid Autoimmune Disorders?
    Free T3 – 2.69
    Free T4 – 0.66
    RvT3 – 12
    Total T3 – 130
    Thyroglobulin Antibody – 2
    Thyroid Perosidase Antibody – 144

  25. Makes total sense why I’m still not feeling well and having hypo symptoms like fatigue, crashes, muscle weakness, aches and pains, as well as concentration and memory problems. Looking at the optimal ranges here, with a freeT3 of 2.6 and totalT3 of 76 I’m clearly on the low end of normal. My FreeT4 is 1.74. My Dr said my FreeT4 is high yet that’s on the higher end of optimal yet he didn’t point out that my T3 levels are on the low end of normal. He’s a nice Dr but it’s obvious he’s still operating old school because he’s not paying attention to my T3 levels. Out of all the info online this optimal chart has been the most helpful. One week into starting NP Thyroid and although I haven’t found my right dose yet I can tell I’m moving towards the right treatment. Thanks

  26. Hi Dr. Childs,

    Thanks for posting this. I am wondering if you have a reference for the chart with the “normal” and “optimal” thyroid lab ranges. I don’t see anything like it on LabCorp’s website (which is where you say it came from.)

    Much appreciated!

    • Hi Erica,

      I believe I used the reference ranges that LabCorp produces which may be slightly different from quest labs and so on. There really is no need for a reference for this because you can just look at any lab test that you’ve ever had drawn and you will see the reference range that they provide. You can probably also find this on their website as well. These companies do not provide an “optimal” range which is why this blog post exists.

  27. Hi Dr. Childs,
    I belong to a Facebook group of hypothyroid people. Most take NDT or a combo of T4 and T3. When posting their results, most have a TSH that is suppressed. If you are taking T3 directly, can you rely on a TSH test? Shouldn’t you instead go by Free T4 and Free T3? In my case, I’m taking Levothyroxine and Liothyronine. My Free T3 and T4 levels are not quite optimal and yet my TSH is suppressed. Since I switched to NDT and then the T4/T3 combo, my Free levels have been better and TSH suppressed. My TSH levels haven’t changed since 9/18 but my Free levels have gotten better as I add more medication. So if I went back to a “normal” TSH, I would be on 1/2 grain NDT and feeling horrible.
    Haven’t you found that the TSH is no longer reliable when the patient is using T3?

  28. I see a lot of people on NDT commenting in forums as well as your blogs and most of these people appear to have lower than optimal levels of T4 and they complain about not feeling stable and weakness. I started to develop severe swelling in my face and excruciating carpal tunnel in my wrist due to the fluid building in my hands while on NDT. My fingers looked like sausages and I couldn’t physically move my wrist. Red raised inflammation started to appear. I immediately quit NDT and grabbed a bottle of my old Unithroid and within two days the swelling went away. It was clear that I had become T4 deficient on 90-105mg of NDT, yet 120mg made me feel overmedicated. Perhaps, had I stayed on 105, maybe maybe those symptoms might have gone away on 105mg but it was too severe. Perhaps I could have added a small amount of T4.
    I think there’s way too much info out there demonizing T4 meds and downplaying the need for optimal T4 levels. In my experience T4 depletion was far more disabling than the low T3 symptoms on Levothyroxine. I’m currently trying to build up my T4 levels again on a different brand and see where my T3 is at after 6 weeks or so and then I can assess if the low T3 was due to the generic Levo or a conversion problem. If it’s a conversion problem then I’ll ask for a low dose SR T3.
    This is a repeat problem I’m seeing on forums, especially on Stop the Thyroid Madness website. NDT did not offer the correct ratio for myself.

    • Hi Terryb,

      You are 100% correct. I’ve never been a huge fan of NDT because of the static ratios of T4:T3 found in these medications. It’s not that they don’t work but instead that the dosing is so rigid that you can’t titrate the T4 and T3 doses as well as if you had each medication individually. The solution that most people recommend (uninformed persons, I might add) is to simply increase your dose of NDT until you feel better. But someone like you will never feel better using this strategy and it may even be harmful to some.

      But be careful in your assertion that T4 is the problem, it’s probably more likely that you are someone who is what I refer to as a “super converter” which means you do much better on T4 compared to T3 because your body can better regulate your T3 levels through T4 than if you were to take T3 via medication. Otherwise, I think your comment is spot on.

  29. Hey Dr. Childs!

    I’ve been on a year long journey now trying to figure out my thyroid labs. I have Hashimoto’s, but have typically been in the “normal” range. Levothyroxine seemed to put me into overdrive so I asked my Dr. If we could trial T3 (liothyronine) and I’ve been slowly ramping up, currently talking 10mcg/day.

    I just got my results back and my TSH is 1.29, Free T4 is 0.9, Free T3 is 2.7 and Reverse T3 is 13. My antibodies are at 28.0.

    I still dont feel great, I don’t feel like I did in the beginning, but I’m still unable to lose weight and have hair loss. I can’t seem to get my inflammation to go away (it usually hangs around 1.1-2.0 but has gone up to 14.0 before). I eat mostly gluten free, dairy free, try to stick to whole foods and avoid grains when I can. I also take b12, zinc, selenium, glutathione, magnesium, megasporebiotic (went through the total gut reset too), d2, d3, fish oil, methylfolate, nrf2 renew, and try to supplement with adaptogens for my adrenals.

    I just don’t feel right and would love another opinion. Thank you for all you do, your content has been so helpful to me throughout this time.

  30. Hi Dr. Childs,
    I’ve suffered with fatigue for decades now. Recently, I initiated a full panel through my NP, to help uncover more about my thyroid. She said that my results came back normal.
    T3 Free 3.2
    TPO <9
    Rev T3 14.8
    TSH 2.030
    T4 Free 1.07
    Age 58 Wt 130, Ht 5'6. B/P normally runs low.

    It will be a challenge to get her to refer an endocrinologist as my results are considered within range. I'm looking to treat naturally with diet, exercise and supplements. Any idea what would be best suited?
    BTW, love your site and the information you are providing!

  31. Hello Dr. Childs,

    Thank You so much for all that you do for the community as a whole. I am 34 y/o female who have been having the “hypothyroidism” symptoms for over 10 year, but never thought it was a problem to treat. Last week, I was diagnosed with Hashimoto disease since my Ultrasound and labs indicated the findings. Enlarge thyroid with nodules and TPO – AB of 362.40.
    TSH3 =1.31
    Free T3= 3.41
    Free T4= 0.9
    Total T3= 118.7
    Total T4= 9.88
    Transferrine Saturation = 16
    I had to go to the pathologist to role out thyroid CA of enlarged nodules with peripheral vascularity and Isthmus calcification. The pathologist thinks I may have CA, but further testing needs to be done. When he saw the above lab results he suggested to monitor the “CA” and not treat the the thyroid since the labs are “normal”. Is it a possibility that the “CA” is causing elevated thyroid function, who mimic “Normal” levels?
    What would you recommend that I should do?

    Thank You again,
    Judy Tam


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