Why Free T3 & Total T3 are the Most Important Thyroid Lab Tests

Why Free T3 & Total T3 are the Most Important Thyroid Lab Tests

The free T3 and total T3 lab tests are among the most important for evaluating thyroid function in your body. 

These tests give vital information as to how your body is processing thyroid hormones

And they give you information about the hormone which is responsible for activating your cells and turning on your genes. 

These basic levels can be assessed and used in conjunction with other thyroid lab tests to give you a very clear picture of thyroid function in your body. 

This post will teach you everything you need to know about free T3 as a lab test and how to understand your levels

What Does Free T3 Tell You About your Thyroid?

There are many ways to assess thyroid function in your body and many different lab tests. 

You are probably already familiar with TSH or thyroid stimulating hormone

This lab test gives you an idea as to how responsive your thyroid is to your brain and if that connection is working properly

But what does free T3 tell you about your thyroid?

Free T3 gives you an idea of how ACTIVE your thyroid is at the cellular level. (1) 

The measurement of free T3 is telling you how much free and active thyroid hormone your body is available to work with. 

Free T3, after all, is the single most important thyroid hormone in your body. 

It’s the hormone that is responsible for attaching to the surface and the nucleus of your cells and making genetic changes to those cells. 

This simple process is what makes your thyroid increase your energy, manage your weight, regulate your cycle, and so on. 

But what happens if you don’t have a sufficient amount of free T3 in your body?

You WILL experience the symptoms of hypothyroidism. 


Because free T3 does all of the heavy liftings when it comes to your thyroid. (2)

If you aren’t familiar with the thyroid conversion process or why it’s so important for your body to go through this process please see this short video below which will bring you up to speed: 


Foods to Avoid if you Have Thyroid Problems:

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The Complete List of Thyroid Lab tests:

The list includes optimal ranges, normal ranges, and the complete list of tests you need to diagnose and manage thyroid disease correctly!


TSH vs Free T3, Total T3 & Free F4

Like most people, you are probably more familiar with TSH as a marker for testing your thyroid. 

And you wouldn’t be alone in this understanding because Doctors also love to use this test. 

But is it the single best test to assess thyroid function in your body? Did you know that there are many other thyroid function tests

The answer may surprise you. 

It turns out that in healthy individuals TSH is probably a great way to assess thyroid function in the body. 

It’s also probably the best way to quickly glance at thyroid function, through lab tests, to determine if the thyroid is “normal”. (3)

But where it fails is when you use it as the only source to help manage patients who are already taking thyroid medication

We know, from recent studies, that TSH fails to predict free T3 and free T4 levels in patients who are taking thyroid medication. (4)

That’s important, but what exactly does it mean?

It means that if you are taking thyroid medication (such as Levothyroxine or Synthroid) that you may have a completely normal TSH, but that doesn’t mean that your free thyroid hormone levels are “normal”. 

This may explain why many patients on these types of medications don’t feel optimal despite having “normal” thyroid levels. 

That’s where free T3 steps in. 

Free T3 can, and should, be used in conjunction with the TSH to ensure that you are getting a sufficient amount of ACTIVE thyroid hormone to your cells. 

And this way of looking at hormones shouldn’t be surprising to you or Doctors. 


Because for virtually all other hormone levels in the body, we ALWAYS check for the active hormone!

If I asked you if your testosterone was “normal” wouldn’t you actually want to know how much testosterone is floating around in your blood? (5)

Well, the TSH is NOT that marker. 

The TSH is a proxy marker for how well the pituitary is functioning but it does NOT tell you how much hormone is in the body. 

When you break it down in this way it just becomes obvious that we would want to look at the active thyroid hormone (free T3 and free T4) but this logic is lost on many patients and doctors. 

Avoid falling into this trap! The free T3 can give you seriously helpful information about how your thyroid is functioning. 

Optimal Ranges for Free (What’s a “Normal” Range?)

But what is a “normal” or “healthy” range? What levels should you look for when you test for this simple lab test?

This is a simple yet very important question. 

The answer is that it varies based on which lab company is drawing and running your bloodwork. 

And that happens for this reason:

Each lab company creates its own “reference ranges” that your result is compared to. 

These reference ranges are based on the results of other people local to your area. (6)

And they often include people of ALL ages and of varying health statuses. 

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That means the reference range is compiled of a bunch of both healthy and unhealthy people which can skew the range. 

When you look at your results you want to be compared to HEALTHY individuals who are around your same age

You don’t want to be compared to someone who is in their 80s with multiple health conditions. 

So how do you do this?

By looking at the reference range and ensuring that your result falls within the top 50% percentile of that reference range

This isn’t a perfect way to do it, but it is much better than potentially comparing yourself to unhealthy people. 

Let’s use this as an example:

This example shows a free T3 of 2.3 with a reference range of 1.7 to 3.7. 

If we break down the difference between 3.7 and 1.7 we get 2.0. 

That means that the top 50% of the “healthy” range is between 2.7 and 3.7 (3.7 being the top end of the healthy range). 

That also means that the bottom 50% of the “less optimal” range is between 1.7 and 2.7 (1.7 being the bottom end of that range based on the reference range). 

So you want your result to ideally fall between 2.7 and 3.7 (in this example!)

You can apply this same methodology to your lab test. 

Is having a High Free T3 Dangerous? (Symptoms of High Free T3)

Just like having a low free T3 is potentially dangerous so is having a high free T3. (7)

In a perfect world, you want your lab test in just the “perfect” zone (the top 50% of the reference range listed above). 

What you will find, however, is that your free T3 will vary based on when you take your thyroid medication, (8) the type of thyroid medication you are taking, and when you check your blood work. 

To prevent abnormalities in your blood work you will want to follow these basic rules:

#1. Make sure to test your blood work about 24 hours after you take your thyroid medication

This will help prevent abnormal highs when testing. 

You want to look at the lowest level of thyroid hormone that is in your body prior to your next dose. 

Checking at hour 24 (assuming you take your thyroid medication every 24 hours) will show you the lowest that your free T3 will be right before you take your medication. 

If this value is in the 50% of the reference range then you know that throughout the day you are maintaining at least that level

#2. Don’t check your blood work right after you take your thyroid medication

This will give you a value that is falsely elevated and not indicative of what your levels will be throughout the day. 

If you still have a high free T3, despite following these rules, then you might be in danger of taking too much thyroid hormone. 

If you do, you will most likely notice it as you become symptomatic. 

Symptoms that may accompany a high-free T3 include: 

  • Jittery sensation
  • Heart palpitations
  • Sweating
  • Hot flashes
  • Tremors of the hands
  • Diarrhea
  • Anxiety
  • Rapid heart rate

If you are experiencing any of these symptoms and you have a high free T3 then you may need to adjust your dose. 

Symptoms of Low Free T3

Perhaps more common than high free T3 is the condition of having a low free T3. 

Most people, due to a variety of reasons, tend to be undertreated as opposed to overtreated. 

Undertreatment of hypothyroidism usually results in low free T3 levels which can be identified when these levels are in the bottom 50% of the reference range (see example above). 

Symptoms associated with this condition often mimic those associated with hypothyroidism. (9)


Because free T3 is the hormone responsible for all of the benefits of thyroid hormone. 

So it makes sense that low levels may result in these symptoms. 

Symptoms of low free T3 include: 

  • Weight gain
  • Fatigue
  • Constipation
  • Cold intolerance
  • Slow heart rate
  • Lower than normal body temperature
  • Brain fog
  • Depression
  • Menstrual problems

If you have these symptoms and low free T3 on lab testing then you may need to make adjustments to your medication regimen. 

This may include using supplements or medications designed to help improve your free T3

What to do to Raise your Free T3 (Medications + Supplements)

There are two main ways that you can improve your free T3. 

The first is through the use of medications and the second is through the use of targeted supplements. 

Let’s discuss medications first:

Low-free T3 when you are already taking thyroid medication is usually an indication that your body is having trouble activating the thyroid hormone. 

In addition, it may be a sign that you are either not absorbing your medication or that your dose is not high enough. 

Either way, you may need to make changes to your medication regimen. 

The easiest way to increase T3 levels is by adding medications that contain this hormone. (10)

Medications such as liothyronine and Cytomel can be added to your regimen which will directly increase T3 levels. 

The problem with this approach is that it requires your Doctor to be on board. 

It can be difficult to convince a physician to provide these medications as they are usually not comfortable using them (even though they are safe!). 

If you fall into this category then you may need to take the supplement route

Certain supplements, available over the counter, can be used to help improve thyroid function and thyroid conversion. 

These supplements may help your body by providing the necessary vitamins and nutrients involved in the thyroid conversion process. 

My personal recommendation is to use a supplement such as this which contains zinc, selenium, vitamin A, and guggul, all of which are designed to help this process. 

The great thing about supplements is that they can be combined with thyroid medications, they are easy to get, and may help a great many people. 


Hopefully, you appreciate the value that testing free T3 can give you when looking at your thyroid. 

Free T3 is available as an easy and routine blood test that is covered by all insurance (I’ve ordered it thousands of times and have never had an issue so don’t buy that excuse!). 

Testing your free T3 will help you to understand if your body activating thyroid hormone in your body and should be used in conjunction with other lab tests such as TSH and free T4. 

Whenever you make any changes to your treatment regimen make sure that you test afterward!

This will help guide your treatment and help you to know what is working and what isn’t. 

Now I want to hear from you: 

Have you tested your free T3?

Do you know if you have a low-free T3 or a high-free T3?

Do you feel that your body is converting or activating your thyroid hormone?

Why or why not?

Leave your comments or questions below and I will do my best to answer! 

#1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4699302/

#2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3687787/

#3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3107420/

#4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3148220/

#5. https://www.ncbi.nlm.nih.gov/pubmed/16705550

#6. https://academic.oup.com/ajcp/article/133/2/180/1760481

#7. https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072598/

#8. https://www.ncbi.nlm.nih.gov/pubmed/8369656

#9. https://www.ncbi.nlm.nih.gov/pubmed/3051835

#10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5167556/

the two most important thyroid lab tests

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About Dr. Westin Childs

Hey! I'm Westin Childs D.O. (former Osteopathic Physician). I don't practice medicine anymore and instead specialize in helping people like YOU who have thyroid problems, hormone imbalances, and weight loss resistance. I love to write and share what I've learned over the years. I also happen to formulate the best supplements on the market (well, at least in my opinion!) and I'm proud to say that over 80,000+ people have used them over the last 7 years. You can read more about my own personal health journey and why I am so passionate about what I do.

P.S. Here are 4 ways you can get more help right now:

#1. Get my free thyroid downloads, resources, and PDFs here.

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70 thoughts on “Why Free T3 & Total T3 are the Most Important Thyroid Lab Tests”

  1. So grateful for your expertise. I’ve learned so much about thyroid disease from reading your posts.
    I feel the worst of my life!! Just had labs. T3 was at the high end of reference range at 178. T4 free was low, 0.79. TSH was very low, 0.019. Thyroid antibodies was normal, 16. Reverse T3 was low end of normal at 9.7. Dr took me off levothyroxine and started me on Armour Thyroid, 60 mg a day. Been on this for about 3.5 weeks so far. I feel really lousy with the entire realm of typical hypothyroid symptoms on an extreme level. My doctor is certainly open to different medications to better regulate but perhaps I should take vitamin supplements you mentioned? I understand you cannot diagnose nor blatantly override another doctor!! It’s just been going on 2 years and my thyroid isn’t getting straightened out. My mother has ovarian cancer and I’m the only one she has to care for her and it’s becoming a personal internal struggle because I feel so bad and she’s the most important one right now!! Any advice would be appreciated.

    • Hi Amy,

      As far as I can tell there is very little downside to using supplements (or at least a trial). They either work and help you, which is great, or you get no benefit from them and they don’t harm you in the process. If you can’t get help from your current provider then using other therapies such as diet, supplements and so on is a reasonable next step.

      • Hello. I purchased and received today your thyroid adrenal reset complex and was wondering if I take 2 capsules at the same time or if it’s better to take like one in the morning and another in the evening? Thank you for a reply if possible!!

        • Hello!

          Yes, most people take 2 capsules per day. Some people find that dose to be too stimulating so they use 1 capsule per day but most do fine on 2 caps per day. Hope this helps!

  2. Hi Dr. Childs, I’m struggling with thyroid symptoms for a few years now. Changed from Synthroid to Naturethroid b/c of severe hair loss, scalp pain, weight gain, fatigue, constipation and depression. Naturethroid got rid of some issues like weight gain and some fatigue and depression but the weird hair loss and severe scalp pain never stopped. I learned at my zinc levels were low at 65 so I now eat 5 oysters a day and it reduces # of hair strands from falling but scalp hurts. My FT3 level with fasting and 24 hours after last dose shows up as 2.3 which I believe is the issue?? I’m also experiencing fatigue again which got better a couple months after I started NDT but is now returning. I’m thinking of adding SRT3 and reducing Naturethroid (I’m on 1.25 grains and multi dose that), my question is how do I properly add SRT3 compounded med without giving myself more hair issues and heart palps? Thank you Dr. Childs.

  3. Hi Dr. Childs:
    So I’m taking 20mcg of Cytomel. 10mcg in the am 10mcg in the afternoon. Just had labs done T3 not even in range (2.5)- (Range is 2.6-4.4) This was after he increased me from 10mcg of Cytomel to 20.
    So, here’s the question. I think my cytomel needs increased so he will probably lower my Nature Thyroid currently taking 45mcg in the am. Does it matter that my free t4 is also LOW? And would your supplement T3 conversion pill be safe to take if I can get him to increase my T3 dosage? Thanks

    • Hi Kelly,

      Our supplements are designed to be taken with or without thyroid medication 🙂 And it seems that some people can tolerate a low T4 but others need it to be optimal.

  4. I have Graves, S/P ablation with Radioactive I-131. Is your criteria the same for me? I am currently using Levothyroxin for hypothyroidism.

    • Hi Charlotte,

      Yep! The lab ranges are the same whether you have a thyroid or not because you still must convert T4 (in the form of thyroid medication such as levothyroxine or Synthroid) into the active T3 thyroid hormone.

  5. I find your website to be extremely informative. I have been on levothyroxine for many years, diagnosed by a rheumatologist due to leg pain. My primary md has been following my thyroid, but in the last few months, my TSH (which is all she screens) have been between 0.04 up to 185. My latest is 0.05. I have all the symptoms you list, except menstrual (I had my ovaries removed after breast cancer). I am so chronically tired, I can take 2 naps after sleeping 8 hours. I don’t know where you are located, but I would love to have a doctor like you. If you know of any that practice your kind of medicine related to the thyroid in the Mount Laurel area of NJ, I would appreciate a recommendation. Please help me.

  6. Hello. When you still have your thyroid and have been hypothyroid and no Hashimotos, can you ever ween off meds like Armour and Synthroid, doctor supervised, of course, to see where you do on your own? I skipped a couple days with no meds because my pharmacy was out of what I use and I felt so much better taking nothing, physically felt better.
    Thank you so much for any reply and expertise you could offer from your thoughts!

    • Hi Amy,

      You can certainly try if you’d like, but it wouldn’t be wise to do it without physician supervision. Some thyroid medications can stay in the system for 4 weeks so you may not feel poorly until after that time.

  7. Morning,
    I have watched your videos numerous times and read your posts. I can’t get enough.
    I have been switched to Armour, 90mg. My Free T3 went up to 5.8 but my Free T4 is still at 1.0. When I was on synthroid, my Free T3 was 1.4. Shouldn’t Free T4 be mid-range? I do feel a bit ‘hot flashy’, but my fingers and toes are freezing cold. I don’t know where to go next.

    • Hi Paige,

      Each person reacts differently to thyroid medications so just switching medications doesn’t mean that your lab results will optimize.

  8. Hi,
    I have been on synthroid for 8 years now. Relatively good numbers on and off however never fully felt great. For past year TSH is low end normal, free t4 is mid to high normal, free t3 us slightly below normal, reverse t3 is high.
    Tried supplementing with selenium, zinc and diet for past 5 months no change in number.
    Dr. willing to decrease synthroid and start t3 slow release at 2mcg.
    Worry/fear is hair loss (it is an ongoing issue with no other outside risk factors), weight loss (I am at a good weight) along with the jittery hyper symptoms. Pro is the potential to feel way better. Would the potential side effects be an issue given I’m not new to treatment and it being a low dose?

    • Hi Sue,

      Unfortunately, there’s no way to predict if you will or will not tolerate the change in your medication and it may take some trial and error to figure out what your body needs.

  9. Hi,

    I have had a partial thyroidectomy and have been on Armour 90mg for a few years now. My current PCP wants to lower it to 60mg since my TSH is .06. He does not check my Ft3 but tests my Tot T3 and FT4. Should I have my Ft3 checked before I lower my dose that much? I don’t feel bad, but he wants to change it d/t my TSH level.

  10. Hi Dr. Childs
    I am following your diet plan and take 50mg liothyronine per day I don’t think my body is utilizing the T3 as my weight will not shift. I have also been using Saxenda for nearly a year which initially seemed to help but as my weight is the same I think it has stopped working. Can you help??

    • Hi Liann,

      If you are referring to my weight loss guide then there are several other therapies listed in there to help you break through a plateau aside from Saxenda and liothyronine. Take a look at some of the other medications in that guide and the video/slides on breaking through a weight loss plateau.

  11. Can you help me select the supplements that I need? My TSH is in the low normal, T4 Free is 1.6 this lab’s normal is 0.8-1.8, my T3 Total is 79 this lab’s normal is 76-181 and my TPA is 1 this lab’s normal is <9. I am very fatigued which is not at all normal for me and have some hair loss.

  12. 2 questions:
    1) I didn’t read anything about the utility of total T3. I usually check TSH, ft3, ft4 but have stopped checking total T3 as I’m not finding it impacts any clinical decision making.

    2) Do you have any data on skipping the morning thyroid dose before testing? This is my training as well but I have not been able to find data to support it. While I do want to see my patient’s troughs, I am concerned about TSH suppression and overly elevated T3 as well, which we’d clearly miss with the skipped dose.


  13. Hi. This was an interesting article. But there are some differences I would like to ask about. I’m not using thyroxine cause I got sick on them and threw up plus a lot of symptoms. So I’m on pure T3 treatment. I have to take my medication 3 times a day. My endocrinologist didn’t even test my Free T3 even though he knew my thyroid is not functioning and I’m only using T3. Since I have to take my medicine 3 times a day it’s difficult to keep 24 hours before blood test. I take my last tablet at 11 in the evening. That gives me about 9-10 hours before I take the test. Would this be fine? Nobody here knows how to follow it up so I more or less have to feel it on my body

  14. There is a process inside the cells which converts T4 to T3 so that it can do its job, and one at the cell surfaces which unbinds bound T4 and T3 so that they can pass into the cells. Doesn’t this mean that all four forms, T4 and T3, both free and bound of each, contribute the the ultimate action of T3 within the cells to regulate metabolism and should be tracked? Especially since many times more T4 is produced than T3, and much, much more of it is found bound in the plasma than free? Granted free T3 is the “quick fixer” that goes straight into the cells promptly to get to work, but I wonder if focusing too much on that number alone risks ignoring other key contributions that affect overall thyroid action and regulation.

    • Hi James,

      It may, but how relevant that is clinically is up for debate. For instance, you can survive purely off of T3 post thyroidectomy which would suggest that if what you say is true, any action would be minimal from T4. I also don’t see free T4 being clinically relevant compared to other measures in my own practice and experience. That doesn’t mean it’s meaningless but I don’t think its impacts is very noticeable.

  15. Hi Dr. Childs,
    I recently had labs done and my TSH is 4.950 (H) , Free T 4 is 0.90 and my Free T 3 is 6.7 (H) I have been prescribed 105mg of Armour thyroid. My symptoms are hair loss, depression, weight gain and fatigue. What should I do ? So frustrated !

    • Hi Kathy,

      The best thing you can do is get a complete set of labs which includes reverse T3 and thyroid antibodies if you’ve never been tested. Once you have that info you can then determine what treatment you need.

  16. I have been on levithyroxin for over 20 years. I am 74 years old and last year I started to just feel off. I was tired depressed on and off with no rI eason. My doctor started me on NP thyroid 60mg with my 100mcg levithyroxin. My last labs were in Nov 2019 and he doesn’t want to test me again until this Sept.
    T4 was 8.6
    TSH .010
    Free T3 3.5

  17. So if your FT3 and FT4 are suboptimal – could that prevent weight loss? to the point where you have tried all things and can not lose an ounce?

      • I just switched over last month from NP to Tirosint. I have used NDT for years now and never saw any improvement switching different brands. Also take cytomel.
        My labs – tsh is .75, which is fine but both T4 and T3 are at the bottom of the range. Taking 75mg tirosint, 10mcg cytomel. i do use supplements – several of yours plus a few others – do I just need to increase both thyroid meds? maybe go to 100 tirosint and 20 cytomel? I am just OVER this! makes no sense????

  18. Yes, I am regularly tested for FT3, FT4, rT3, Total T3, Total T4, and TSH. After reading your article on T3 testing, I discovered that I should wait 24 hrs. from taking Cytomel and Levothyroxine to get accurate results. I will make sure to do that in Sept. when I get retested. My June 2020 blood test showed my FT3 level was high (5.89 pg/mL), my Total T3 was very low (2.03 ng/dL) and my levels were off because I had run out of Low Dose Naltrexone (LDN) which helps with cell penetration and autoimmune symptoms. Without that medication, T3 stays in the bloodstream and does not penetrate my cells. My blood tests have shown that I do not convert or activate thyroid hormone. LDN helps with those processes.

  19. I had the left half of my thyroid removed 20 months ago due to a nodule (non-cancerous). I am a mid-60’s male, was not experiencing any thyroid issues other than the nodule. I have not taken any med post-surgery. Not experiencing any overt symptoms, but TSH has been around 5, T4 =1.4, T3 = 3.1 — T3 was at 4.1 a month after surgery. Is it too soon to feel my thyroid will not return to normal function? Should I start thinking about taking a supplement to boost my T3?

  20. Hello. I had many hypothyroid symptoms as I entered my early 50s. Endocrinologist always maintained my labs met the reference ranges. Began to put on 4 lbs/year w/ absolutely no changes to diet or exercise. Did a keto diet and lost 13 lbs– which was adequate for me. At that time due to post-menopausal state and hypothyroid s/s, my functional medicine MD felt I could use a T3 boost as my T3 was 2.5.It went as high as 3.0 after 5 months of Cytomel at 4-5 mcg.
    JUne 2018 labs:
    T4: 1.35
    TSH: 3.02
    T3 Free: 3.2
    Reverse T3 13.0 (down from 19 2 months prior)
    A year later I began to put on weight rapidly, again, with no change to diet or exercise. I had my labs retested this past June 2020 and on 5-10 mcg Cytomel:
    T4: .74
    TSH: .46
    T3 2.85
    Reverse T3: 12
    I guess it stands to reason that my TSH would decrease given the Cytomel. Not my functional MD, but a 2nd opinion endocrinologist said I don’t even need T3 and it is causing my TSH to become low putting me at risk of A-fib, dementia, and osteoporosis, and thinks I should come off.
    My functional medicine MD is adding Tirosint 25 mcg along with Cytomel— I will wean off my 20mcg down to 5 or 10.
    I would appreciate your feedback on this co-management given the labs I listed. Much thanks

  21. Thank you so much for this website and all of this information. I had a thyroidectomy due to cancer and after they just sent me off to an endocrinologist with a prescription for synthroid. That was almost two years ago and I’ve been on a steady decline ever since. Finally I called the endocrinologist to say how I felt awe full and had been declining for two years and that I wondered if I wasn’t converting the t4 to t3. He just started yelling at me and asked me what kind of person what’s two years to go to the doctor(I go every 6 months). Then he said everyone wants to blame their problems on the thyroid(I don’t have a thyroid)and he left. I left feeling pretty abandoned by this specialist. I asked my primary dr to test free t3 and it’s 2.3 with the reference range of 2.2-4.2! I have started taking most of the supplements you have recommended and I hope it will help me. I thank you so much for putting this info out there for thyroidless patients like me who’ve been abandoned by their own doctors

  22. My FT4 is at the low end of the range. And FT3 has moved to the low end of the 2.41 (low end of range is 2-18). I’m on 13 mcg Tirosint and was on 5 mcg cytomel after Naturethroid recall.TT3 is .97 (range is .6-1.81). My gut was really messed up in late Sept by Armour for 5 days. I use L glutamine, 40B Douglas Labs probiotic, selenium and zinc. I went off cytomel because my stomach isn’t so bloated. I see my doc to talk about last labs. Which of your products would be good for my situation? And do you do consults?

  23. Thank you for this information. I discovered I had Hashimoto’s about 10 years ago although I have been on Synthroid for about 20 years. I am 63, 5’2″ and 127 pounds. So when I found out I have very high cholesterol and pre diabetic, the usual advice about loosing weight doesn’t apply. I went back and looked at a thyroid test from 2020 and my Free T3 is just barely in the “normal” range by .4! I am on 75 mcg of Synthroid. My cholesterol has been creeping up for the past few years, despite a gluten free, low carb diet. I have added zinc and selenium, and hopefully I can speak to my endo about Cytomel at my next visit, if the supplements don’t help.

  24. My doctor said my recent thyroid tests are fine but I wonder about the numbers. T3Free 6.3 pg/ml. T4 7.1 mcg/dI. TSH 0.22 mcIU/mI6. From the paper I was given with these results it appears TSH is low while T3Free is high. Is this normal? I’m 77 and have been on Armour thyroid since I was diagnosed with hyperthyroidism at about 45 years of age. Thank you very much. I enjoy your videos!

  25. Dr. Childs,
    I am 47 years old, post-gastric bypass (roux-en-Y) patient. As predicted by your blogs, I’m finding it insanely difficult to get any physician to believe that my weight gain is the result of anything other than overeating. I have never returned to overeating since prior to surgery. What I have experienced is significant malnutrition problems from damaged small intestine. I’ve also had increased weight gain lately with no changes to my eating. I read your website and I went to my doctors requesting the labs you suggested. The labs that they did run for me resulted as follows: TSH 1.42 (ref. .47-4.68); T4 4.9 (ref. 4.5-11.7); Free T4 .78 (ref. .70-1.48); Free T3 2.6 (ref. 2.0-4.4); RT3 8 (Flagged as low with ref. range of 9-27). I went to an endocrinologist who seemed to mock me for asking her to consider that my metabolism had shut down or was in “energy saver” mode and further advised me to begin the Mediterranean Diet. My PCP is amazing and tends to at least listen to my requests but I can tell she’s not on board and probably doesn’t believe that I’m not overeating either. Can you A) Suggest a jumping off point with your supplements? B) Point me towards supporting research that may help my physicians to see things in a different light? My previous nutritional deficiencies are well on their way to repletion. The weight regain (with the “fibromyalgia” diagnosis and all its associated symptoms) is the final piece of my puzzle that I need to focus on. Thank you so much, in advance.

  26. Last time I had my labs done to check thyroid levels I had taken my desiccated thyroid med (30mg) two hours before my lab work. I have always done this. Won’t now!!
    My T3 was above range and T4low end of range. Tsh was 3.11 (Canadian ranges are different) it’s close to higher end of range. I’m confused!! Wouldn’t tsh be lower if T3 so high. Anyway my symptoms are those of hypothyroidism. Im on the lowest amt you can take. Any thoughts? Guessing it’s actually low and T3 showed high bc I had just taken it??
    I’m tired, gaining weight a little, and very cold.

    • Hi Lori,

      Unfortunately, it sounds like your lab results are not accurate given when they were drawn so it’s somewhat pointless to try and make assertions based on them. I would recommend reading this article to make sure you get accurate lab tests so they can provide you with information that you can act on: https://www.restartmed.com/thyroid-testing/

  27. Hello Dr. Childs,

    I have a 16 y/o daughter who has had low free T3 levels for two years. Her levels are significantly out of the normal range. Her TSH, T4 & Reverse T3 are all on the low end of normal. She has all the symptoms of hypothyroidism but no one is willing to treat her. She has stumped endocrine and the functional medicine specialist we are working with. Any thoughts?

    • Hi Michelle,

      Has anyone checked her hypothalamic function? If she has a history of excessive work outs or excessive dieting then she may have low thyroid from suppressed hypothalamic function.

      • Hi Dr. Child’s,

        They have looked at FSH, LH, ACTH but I’m not sure what labs would look at hypothalamic function? How would suppressed hypothalamic function be treated? I personally feel the trigger was stopping ADHD medication (Adderall) two years ago. I think taking Adderall is probably similar to excessive dieting and I’m guessing it does impact the feedback between the thyroid/pituitary/hypothalamus. I would just like to find something that can restore her metabolism and eliminate the extreme fatigue she experiences. Any articles or suggestions would be most appreciated.

  28. I just stumbled upon this site while trying figure out why I feel so terrible. I’m looking forward to reading more as I try to get to the bottom of these issues I’m having.

    My thyroid results:
    Free T3 = 5.0
    TSH = .914
    free T4 = 1.07

    All the other non-thyroid tests were in normal reference range.

    I’m 46yo female on natural desiccated thyroid hormone. I had a thyroid lobectomy 10 years ago to remove some scary nodules that were somehow (reportedly) making their own hormone. I was told that my thyroid went into a hypothyroid state shortly after the surgery. The single love didn’t seem to be able to carry the weight of the other lobe.

    Symptoms I have are always tired, depression, some anxiety, insomnia, concentration issues/fogginess, unexplained shortness of breath (maybe damage from COVID), headaches, nausea, slowed metabolism. I am so sick and tired of feeling this way. I’m missing out on what should be the best years of my life. I am blessed in so many ways, but I feel totally robbed by all of this.

    I’m also on Wellbutrin, which seemed to help for a while (a few months).

    Any words of wisdom would be greatly appreciated!! Thank you.

  29. Well since starting peri menopause I’ve also discovered my T3 at the very low range. However tsh & t4 was in normal range.
    I’m guessing this is why I’ve gained weight for first time in my life, I use to have high metabolism.
    I want to stay on top of it so a doctor agreed to start me on a low Armados. By T3 is now in the normal range heading to the above 50%.
    However T4 and TSH has fallen to lowest ends on range. Is that a problem? Thank you!!

    • Hi Stacy,

      It can be but it isn’t automatically a problem. It depends more on your symptoms, your age, and other medical problems that you may have. Lowering your TSH does increase your risk of problems but these are minimized in younger women, for instance.

  30. Hello, Dr. Childs –

    I’ve been on .025 mg of Levothyroxine now for 2.5 years. I don’t have any negative symptoms of thyroid disease. My thyroid was tested when I talked to my doctor about losing lots of hair, which can also be an aging thing. I don’t take any other meds. I don’t like taking the Levothyroxine. I had another Thyroid Panel done just a week ago and my T3 free number came back as 2.4 on a 2.0 – 4.4 scale. All the other numbers were good. My doc said there wasn’t anything to worry about if I was feeling okay, which I am. I just read that a thyroid test shouldn’t be done if a person has just taken the medication. I took the .025 pill about 1.5 hours before the blood was taken for the tests. I’m wondering a couple of things: 1. Can natural supplements take the place of and be as effective as the Levothyroxine; and, 2. Do you know if having lots of dental ex-rays done could effect thyroid levels. I had a bunch of dental work done at the same time I was diagnosed with the thyroid problem.

    • Hi Gail,

      Theoretically, yes, but you’d need to have a LOT of x-rays. The thyroid is very sensitive to radiation but the radiation dose from a single x-ray is quite small.

  31. Dear Dr. Childs;
    I am 87 years old. As 03-Oct-2022 my TSH 3.480miU/L T3=2.4pg/ml
    T4=10.60 pg/ml Iode55.0 ug/L Estradiol=78.6 Testosteron=9.55
    My question: Why I am tierd and having a hard time to get out of the bed.
    Is this a Thyroid problem?
    Thank you.

  32. Hello, first I am so very thankful for all of your resources. I have been hypothyroid for at least 7 years and I am 57 years old. My Doctor just ordered labs, its been about 6 months and I am taking NP Thyroid, the only labs she ordered is TSH and Free T3, I asked for Free T4, reverse T3, and Total T3, she said that I do not need those labs because I am taking NP Thyroid. Is this correct? Should I order them on my own? Look for a new doctor? Thank you

    • Hi Linda,

      No, that is not correct. If anything, it’s more important to test your free T4 and total T3 because you are taking a medication that contains T3. You don’t necessarily have to order them, though, if you are feeling great. They would really only be necessary for optimizing your dose but if your dose is optimized due to luck then you may not need those tests.

      If you aren’t feeling 100% then you would probably want to seek out a second opinion from a more thyroid-literate doctor: https://www.restartmed.com/how-to-find-a-doctor-to-treat-your-thyroid/

  33. Hello,
    Thank you so much for putting out all the wonderful resources. Trying to read and absorb the information. I do have a question/concern. My recent labs showed a TSH of 0.12 and FT3 of 4.4. Due to TSH low and FT3 high, my doctor told me to stop taking the liothyronine and only take Levothyroxine. My dosage is Levothyroxine 0.075MG and
    liothyronine 5MCG daily. Will taking only the Levothyroxine work by itself or be too much and create an imbalance? Can you experience weight gain with taking just Levothyroxine? Thank you so much

  34. Thank you so much for this information. I’m still not sure how to calculate the top 50% for my lab values. I did read the article on “optimal levels” and can use it to approximate what mine should be, but I’d really like to understand the calculations to get to the top 50%.

  35. What are some things that could cause an elevated TSH and elevated free T3 with a normal T4 and total T3 in a healthy 23 year old male?

  36. HI,
    My recent bloodwork came back “fine” according to my endo.
    TSH 0.5 / .3 antithyroglobulin / 0 thyroglobulin / But my ft3 is 12.8
    I feel this is too high and not “normal”
    I had my thyroid totally removed because of cancer and am on 100 of Synthroid daily.
    Please let me know your thoughts.

  37. I went to a functional medicine dr and he said I had a conversion issue, no beginning Hashimoto’s, and then ignored my thyroid the remainder of the visit. Needless to say I will be attempting to find another, but any advise on where I can start until then?
    I am 37yr old female, 5’0″ 99lbs.

    TSH: (70th percentile)
    fT3: 2.8 (33%)
    total T3: 108 (33%)
    T3 Uptake: 1.13 (66%)
    fT4: 1.07 (28%)
    Testosterone, total: 23 (29%)
    anti-TPO : <9 (range <35)
    Thyroglobulin Ab : 14


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