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Low T3 Syndrome V: Should It Be Treated with Thyroid Hormone?


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This article is part of a special report on Thyroid Disorders. To see the other articles in this series, click here.

In this final article in the series on Low T3 Syndrome, we’ll discuss whether thyroid hormone replacement therapy is an appropriate treatment in these cases.

Why T3 Levels Are Low

Unfortunately, there are few studies that have examined this question specifically, and even fewer that have explored the question of whether T4 or T3 (and which type of each) would be the best choice.

As a clinician, my primary concern is always primum non nocere, or “first, do no harm.” From this perspective it’s important to recognize that the changes seen in Low T3 Syndrome may represent a restorative physiological adaptation by the body to chronic illness.

In other words, T3 levels are low because the body is attempting to conserve energy and resources to better cope with the challenges it is facing. Increasing thyroid hormone levels in this situation could conceivably have adverse effects.

For example, the changes observed in the thyroid axis in acute illness are similar to those observed in fasting, which can be interpreted as an attempt to reduce energy expenditure and protein wasting. (1) Giving fasting subjects thyroid hormone results in increased catabolism (breakdown). (2)

In cases of chronic illness, however, it is less clear what effect thyroid hormone replacement has. The few studies that have been done produced mixed results. (3)

Some studies show that treatment causes harm, others show no change, and still others show an improvement. After reviewing the literature on this, I’ve come to the following tentative conclusions:

  • T4 is rarely, if ever, effective in Low T3 Syndrome and may even cause harm. This is probably due to the decreased conversion of T4 to T3 that is seen in chronic illness.
  • T3 replacement has been shown to be consistently beneficial only in cardiac patients who’ve recently had surgery, heart failure or a transplant.

That said, I’ve heard anecdotal reports of improvement from people who have taken replacement T3 hormone for a condition called “Wilson’s Syndrome” (which does not exist in the scientific literature or according to any mainstream medical organizations). Wilson’s Syndrome refers to low basal body temperature and other nonspecific symptoms occurring in the presence of normal thyroid hormones.

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I’ll be the first to admit that “lack of evidence is not evidence against,” and as I mentioned earlier, there’s not a lot of research on the effectiveness of T4 and T3 replacement therapy in Low T3 Syndrome. It may be that as we look into this further, we’ll discover a role for thyroid hormone replacement in these conditions.

That said, I think caution is warranted.

Taking T3 when you don’t need it is potentially dangerous. It can significantly upregulate the metabolic rate and lead to cardiovascular complications in some patients.

And, if the changes seen in Low T3 Syndrome are a compensatory adaptation of the body in response to chronic illness, increasing T3 levels artificially may have undesirable effects.

In the majority of cases of Low T3 Syndrome, I think it’s preferable to identify the underlying cause and treat that. As I discussed in articles #3 and #4 in this series, those causes most often include infections, autoimmunity and inflammation.

Articles in this series:

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Join the conversation

  1. Hi,
    I’m only 27 years old and i was diagnosed with hypothyroidism about a year and half ago.. my TSH was a bit high T4 was normal and T3 was a bit low… doctor started treating me with levothyroxine 25mcg 6 months later TSH was still a bit high T4 was normal and T3 was a bit low so she increased my dose to 50mcg.. 3 months later she ran some blood work again, TSH came back normal T4 was normal but T3 was still low. She decided to give me Liothyronine 5mcg twice a day.. 3 months later (this past weekend) my TSH came back VERY LOW, T4 was high & T3 STILL low… any ideas of what could be happening? Before i was diagnosed i did have symptoms of hypothyroidism, i was always tired, and gained quite a good amount of weight about 100lbs since i went with this untreated for about 3 years, constipation, dry skin, my hair got very curly (didnt expect that).. ever since my doctor has been giving me levothyroxine i have lost about 60lbs.. and now everything seems to be off balance… i feel tired all the time again, my appetite has increased a lot and im still losing weight but she says it has nothing to do with my thyroid. She referred me to an endocrinologist which i should be going to this week.. i feel like my lab results have been all over the place since i started taking medication and my numbers have never been awful until NOW… they were always SLIGHTLY off and now they’re totally off.. i feel like i was over medicated just trying to bring my T3 to a normal level and now the rest is out of whack.. is there any reasons why my body is still not producing enough T3? i dont know if this helps my but testosterone levels have been abnormal as well which my OBGYN wants to start treating soon i just havent given her an answer yet on that. Any advice would help, could something else be wrong with me? a few of my family members have already had their thyroid or part of their thyroid removed and i dont want to go through that. Thanks

  2. I have been off work now for over half a year. I have Hashimoto’s, my T4 is at the very top of normal range (occasionally higher), T3 at the very bottom of normal range, TSH is normal. On a lower dose of Levothyroxin the T4 came down slightly and the T3 went below normal range, TSH was at upper normal. My functional, integrative doctor has deplored the ratio between T4 and T3 and believes it’s a conversion problem, the Endo says everything is perfect and laughs at the various supplements given to me by the functional doctor. My GP says I have fibromyalgia. I sometimes have muscle pain, am always completely exhausted, have heart palpitations, can not sleep well (much better on lower T4), get dizzy unexpectedly (have fallen down the stair and broke my foot), have no appetite, vision, concentration and speech problems, tinnitus and a whole host of minor other problems. Having had a history of undiagnosed thyroid problems, which presented in very similar but not as pronounced ways, I tend to side with the functional doctor. He wants me on the supplements for 4 months and then take it from there. In the meantime I’m at home alone developing symptoms of depression and really sometimes wanting to give up (on everything). Any thoughts on that? Not that it matters in the sense that the docs will still do whatever they do, regardless. Still, it would be nice to hear some opinion on the matter.

    • Hi,
      I have Hoshimotos. Not sure how I got it or when. I was diagnosed at 4yrs old. My mother and grandfather also have it. I’ve had symptoms my whole life. The drs would never give me medication because, while my antibodies were so high the test couldn’t measure them, and my thyroid was always swollen, my actual thyroid levels were within range, for Western medicine anyways. Long story short, meds helped minutely. It wasn’t until I started a 6 month program with a holistic/functional?? Dr. I ate a completely clean diet and for the first 2 months an autoimmune diet. I stopped the meds and a couple months later rechecked my levels. Everything was normal. The tinnitus was gone, the weird pain in my ears, the tachycardia, sleeping much better, not getting up all night to pee. The list goes on. Not all my symptoms were gone as I had other health issues to deal with, like Lyme disease. I continue to take different supplements to heal different parts of my body. Dont expect a quick fix. Healing takes time. Im 11 months in (minus the bad eating) I have been eating bad off and on the last couple months. My tsh is crazy high, of course my dr (VA) didn’t bother with t3 or rt3. And many of my symptoms are back. I cannot stress enough, before you start taking pharmaceuticals to try the holistic approach. Heal your body, not treat your symptoms. Since I started the program I am off all my meds. Mood stabilizer, antidepressants, metformin, blood pressure meds for my tachycardia, thyroid meds. I do still struggle with anxiety but nothing like before. Good luck and don’t lose hope. God brilliantly made our bodies, and when we treat them how he intended, they work brilliantly.

      • Thank you so much, Elisabeth. I have had Hashimoto’s for at least 40 years. When I was diagnosed with it, my thyroid had atrophied severely and I was terribly hypo. Since my thyroid is completely destroyed I will unfortunately have to supply my body with the missing hormones. I have found an integrative/functional doctor, who stated that the ratio of T3 to T4 is completely off. He believes that my body is so run down at this point that giving me the T3 will damage my organs. So he did the same as you suggest as the very first step…….he gave me a food plan. Now, the food plan is identical to my usual diet, so I did not have to change much. But he also recommended a whole number of supplements to boost my mitochondrial health, which I have been taking for 4 weeks now and they seem to slowly start to kick in. I have refused to take the antidepressants and neuropathic pain medications (stepping on doctors’ toes big time) and am glad I have, because while I’m still very, very exhausted the pain is starting to subside and my concentration is getting better as is my vision. The incidents of speech problems occur only towards the end of the day when the exhaustion reaches its peak. Some other things have not improved…….yet. My hope is that by the end of April, when I go back to see the functional doctor (unfortunately I have to fly out to see him) everything has improved quite a bit as it will be 2 more months of supplements until then.
        I really appreciate your encouragement, Elisabeth. It is not easy to upset doctors and my insurance has refused disability payments on the grounds of me not taking the recommended medications. But just like you I feel that putting chemicals into my body for no good reason will do more harm than good…….better poor and healthy than not exactly rich and ill. 😉 I just needed to hear this from somebody when I was getting pretty desperate and came within a hair of agreeing to take the prescription drugs (there had been no discernible improvements at that time at all). So your words and the recent small improvements encourage me to stay the course and……..to heck with the doctors here and the insurance company. And good luck to you, as well, with losing your anxiety and having your health restored to the fullest.

      • I just realized that I have other low thyroid symptoms besides low body temperature: tinnitus and depression. Also I have to sleep with a mattress warmer.

    • Do a little research on Iodine. Watch your consumption of fluoride, bromide and chlorine.

      • There is a group I found through StopTheThyroidMadness that discusses correct levels and how to get there. It’s a natural desiccated thyroid group, but there is a list of thyroid groups that have experienced moderators that likely may be able to point you in the right direction

    • Adrenals. A saliva test can determine how they are functioning.
      Go to the stop the thyroid madness site. They have tests you can order yourself, if your physician won’t. You may also have hashimoto’s thyroiditis, an autoimmune disease. You should have your thyroid peroxidase, and antibodies checked along with Reverse T3/T4. I also have had your symptoms; ginger has helped me, it doesn’t work for everyone. I bring about an inch of ginger root sliced up in 4 quarts of water to a boil, then simmer for 20 minutes and drink at least four cups daily. It takes a couple of weeks to build up, lemon helps with the taste if you do not like it, some honey also, if you do sugars, I don’t, coconut oil helps also. I also use magnesium oil. You don’t have the effects as you do by taking it orally. I was plesantly surprised at how this has helped with joint, muscle, and nerve pain. I also use homeopathic remedies for nerve pain and helping sleep. Passionflower is a nice evening tea. Hope some of these help you out.

  3. I have high RT3, low T3 and T4. I have been on 81.25 mg of NDT & 15 mcg of compounded T3 . My numbers do not get any better – and my TSH is at .01, of which I was under impression NDT suppressed TSH? I have severe constipation, insomnia, cold hands and feet (hands will get so cold feels like they are in ice water) and thinning hair. Dr and I decided to try just compounded T3. I switched straight over to 75 mcg of compounded T3. Now I have night sweats, still constipated and my insomnia is worse.
    My iron is low, taking desiccated beef liver capsules with vitamin c and bio flavonoids. I eat a lchf diet, exercise and strength train daily plus walk 2 miles a day. Very little to go off of, I know – but any thoughts?

    • Have you had both circulating iron and ferritin checked? Ferritin is iron storage. If it is low, your thyroid will not improve and you will always be cold and have cold limbs because your blood is not oxygenated and healthy. You also need to make sure your adrenal glands are being treated. You need to make sure you have proper levels of adrenal hormones as well for your thyroid to be utilized properly.

      I had to have intravenous iron treatments for 4 years during which time no one would address my thyroid issues but now that my blood is healthy, I don’t experience as much coldness. Still have cold feet but not so much in summer. I take bovine adrenal glandular supplements and prenenelone and DHEA in addition to sex hormones and am now experimenting with thyroid as I have Hashi’s and a RT3 issue also. I still have constipation but mostly when I eat something that is high carb or contains an allergen.

      I follow a Paleo/Ketogenic diet and if I stick to eating ‘high fat’ then I lose weight and feel great. If I let too many grains in or sugar, everything stagnates. I avoid gluten and I try really hard to avoid dairy so I cheat sometimes b/c it’s my favorite and avoiding just breaks my heart. I probably only have one serving a week in a meal where I can’t help it.

      You may also have some systemic illness affecting your immune system. I was treated for intestinal bugs and am still fighting candida and mold illness.

      I hope you feel better. Good Luck!

  4. I have been feeling a whole host of issues, I’ve been tired, dizzy, weak, joint pain, painful heartburn, etc. I’m in my early forties so I suspected it was hormonal. I just got a my blood work done and My estrogen is really high, my naturopath says I’m “estrogen dominant” , but i was surprised to find my cholesterol was super high and my T3 was low (1.9) . My T4 was normal.My naturopath believes in Wilson Syndrome and due to my low basal temp and T3 wants to put me on a round of free T3 therapy. It lasts for about a month and a half. It supposed to boost our T3 levels back up. I’m worried after reading this article that maybe it can cause more harm than good. Any thoughts?

  5. I’ve been to numerous doctors trying to diagnose my eczema, dizziness and short/irregular cycle and the most recent doctor ran a panel of blood work and said that my T3 was just below range. My TSH and T4 levels are normal. The T3/R2….. was just below range (1.79). In addition my billirubin is high. They suggested putting me on a slow release T3 hormone but are not certain I have a thyroid issue. Everything else related to my liver function is normal. Do you have any thoughts or suggestions for additional testing?

  6. Couple of questions to add to the conversation:
    – Any benefit to observing/acting on fT3/rT3 ratios?
    – If fT3 levels continue to fall despite increasing dosage of T4, is it sufficient to just add T3 therapy, or should we be looking into whether chronic or acute illness could be causing this drop in fT3?
    – Does ferritin / iron play into T4/T3 conversion?

    I’ve been on T4 (Synthroid/levothyroxine) for over 2 decades, but my TSH levels were rarely stable, and in the last few years started widely fluctuating. In the last 12 months, my TSH was normal, fT4 slightly elevated, and I began experiencing palpitations that did not subside even when T4 dose was reduced and TSH/fT4 came back to normal. I finally convinced my PC to refer to an endocrinologist, especially since she refused to test anything but TSH and fT4 (and only would test fT4 if I practically begged) and couldn’t get those labs to stay stable for more than 90-120 days at a time.
    The endo ran a full screen that included antibody tests for both Hashi’s/Grave’s, gluten and other sensitivities, and found I am definitely Hashi’s. Over the 120 days I’ve been working with my endo, we’ve also tested everything in the HPA axis.
    Key Findings:
    Cortisol normal – While my morning cortisol numbers were slightly below normal range, they respond appropriately to both ACTH and dex stimulation tests – doc says everything there is normal. I’m curious why my morning levels would be outside reference ranges and that’s considered normal…… have to investigate that later as right now T3 is the priority.

    Thyroid – TSH and fT4 respond to T4 treatment, but fT3 does not
    150mcg levothyroxine for 1.5 years until the above episode, lowered to 134mcg. 3 months in (when I met my endo), switched to brand Synthroid, 134mcg. 6 months after dose was lowered, began to feel typical ‘thyroid tired’ and brain fog. It continued to worsen, I gained 25lbs in 2 months, could barely stay awake through the work day, and despite adding in 13K steps per day and morning workouts 5 days a week, saw zero lean muscle gains, experienced facial inflammation, Shjogrens, pitting ankle edema, kidney pain, and a very strange heavy feeling in my limbs. In the 20 years of being hypothyroid/on T4 treatment, symptoms had never been this severe. Doc increased Synthroid to 150mcg, with no symptom relief. after 90 days, 2 rounds of serum tests showed TSH had increased on both rounds, fT4 remained normal/stable, but fT3 was dramatically decreasing. Doc ran an rT3 recently and it came back in the high end of reference ranges. This creates an fT3/rT3 ratio of 10.2 – I’ve seen sites indicating a ratio of 20 or above is ideal – but I’m not finding much in the way of medical literature or studies to support ratio consideration. If anyone has anything that could support ratio as a consideration I’d be quite grateful….
    Doc added 5mcg Cytomel – she was concerned about the palpitations so started me on a very low dose. Ironically I self-treated with increased iron-rich diet and iron supplement, although a recent ferritin test (for telogen effluvium) turned up in the very bottom of reference ranges. Palpitations are gone after supplementing, thank goodness.
    Adding just 5mcg of cytomel had a dramatic effect after just 5 days. Saw significant improvement in fatigue, brain fog, aches, kindey pain, and heavy limb feeling dissipated. Didn’t realize that my hair had become limp and lifeless (in addition to the hair loss that I DID notice, yikes!) but this low does of T3 has brought back the normal body and shine (yay!)
    However, after 2 weeks the fatigue and kidney pain are starting to return. I’ve asked my endo if we can test serum levels of fT3- we’ll see what she says. It seems her pattern is to add or make therapy changes based on abnormal or suboptimal labs, but then not order follow up labs for 90-120 days. Most literature I’ve found indicates appropriate follow up for T4 changes is 30-45 days, and for T3, 2-4 weeks. Thus far she’s responsive if I press issues, but ideally I’d like to work with a practitioner who provides education and follow up, without patient having to drive that 100%.

    So – to respond to the request from this article – T3 therapy seems to be having significant positive effect on my symptoms, but its probably too soon to say whether I’m optimized, and what, if any effect adding T3 will have on my fT4, rT3 and TSH labs. I’m concerned as to whether we should be investigating anything outside of HPA to determine the cause of plummeting fT3 but don’t know where to start (CBC and BMP/CMP show nothing outside reference ranges, but do see increasing WBC and a few other indicators at the ‘edge (high/low)’ of reference ranges).



    • Taking t4 only in close to 100% replacement for 20 y, is out of balance therapy but you coped well now when getting older you get t3 lvl low, you need to add just a tiny amount of t3 to it and it will make wonders, if your ferritin is bad this is clear sign your thyroid hormones are not balanced for a longer period of time probably more then 10y, add some real vit A to help iron building and add a bit of t3 , to it and you will be fixed in 2 years time……looking at rt3 is futile business and i so wonder who made that stupid thing up! Its so irrelevant

      • To the commenter on checking rt3, no, it is not stupid. I’ve seen a couple comments to that effect and I can’t help thinking how uninformed and ignorant that is. If your doc doesn’t know how to check reverse t3, how to correct the ratio, then find a doc that does.

        • amen daniel,,,wow how uninformed people are and making statements knowing nothing about what they are talking about,,the ft3 to rt3 ratio is what cured my wife and lost 50 pounds of belly fat just correcting that ratio,,going fro 10.3 to 24.7 gave her life back

      • Hi Ivy,

        I appreciate your response although most of the comments don’t relate to questions posed. As for the rT3 being a stupid made up irrelevant thing, you couldn’t be further from correct.
        I’m not a medical practitioner, hence I asked the questions I did. I am however, in possession of a degree in biochemistry (albeit more than a few years old lol). The chem geek in me shares this: the deiodination process cleaves an iodine molecule from T4 – if it cleaves it from the outer carbon ring, active T3 is produced. If it cleaves it from the inner ring, inactive (or rT3) is produced. If a majority of the deiodination process creates inactive T3, or rT3, and that is what binds to receptor sites of tissue, then the rT3 is causing a serious problem at the cellular level by blocking cells from receiving active T3. So, you can see rT3 is not a stupid made up thing, and it can be VERY relevant to hypothyroidism.

  7. I was an idiot. A reproductive endocrinologist said my t3 was a little low and put me on synthroid. I became pregnant and he increased it in my 7th month. I became anxious and unable to sleep, but chalked it up to pregnancy. I took that medicine for 13 years, was anxious, depressed, and couldn’t sleep the entire time, but attributed it to stress and inability to cope. I began losing my memory. I quit my job. I went to Dr after Dr trying to find out what was wrong with me. I told one Dr I felt horrible within 15 minutes of taking synthroid. He switched me to armour. I told another Dr that I felt so much better when I forgot to take my thyroid meds out was like a happy mania. Poor choice of words because he suggested I see a psychiatrist. Finally, a friend who started thyroid meds asked me if it made me feel worse to start. That’s when it all clicked. I never was clinically hypothyroid and yes, I’ve felt like crap for 13 years. The last year I thought I had dementia and had sensations of my brain shaking like a flexed muscle inside my head. I’ve been off thyroid meds for 4 months and don’t experience that anymore. My memory is much better, but I still have moments, sometimes days when I feel drunk. My thyroid levels were perfect while on thyroid meds and they are perfect now that I’m not. Very strange, but god knows what damage I’ve done to my brain.

    • I really sympathize with you, the brain is very plastic and it has ability to recover ,but it will take you probably 3 years at least to recover that damage from t3..and its not only brain…..so be patient and eat foods good for brain, take quality omega 3 oil supplemets every day, dont overdose on anything, and go early to sleep….i sympathize with all the people who take wrong therapy, its sufficient to take just 10% more or less then needed to be out of balance….and its 50% of people who are on wrong therpay this is data that usa endocronology association said in their own reports! So sad when things are basically very simple…..too si ple that in 2017 people still cant figure out what is balanced thyroid hormone replacement! And its not t3 only!it never will be

    • Oh yes taking 134 t4 is little too much, it should be 120 or so…..134 is just 10% too much, the balance must be in -+ 2% of ideal 10% more and you are overdosed! And pushing t3 lower…..the ideal dose for you is based on absorption but if thats not good also work on your gut! And reduce that t4 it cant work otherwise

  8. I recently found an excellent 2015 article focusing on the phenomenon of “poor conversion” from T4 to T3 thyroid hormones in hypothyroid patients treated with thyroxine (T4, Synthroid).


    Their study was based on 353 subjects on T4-only therapy who had reached a stable “euthyroid” status (defined as TSH 10pmol/l). Their subjects were divided into three categories:

    1. patients who had had carcinoma (who had had thyroid surgery and were taking a large dose of T4 in order to suppress TSH),
    2. patients with “AIT” (autoimmune thyroiditis), and
    3. patients who had had non-cancerous “Goitre” (after surgery to remove thyroid nodules).

    The results showed that people with less of a functioning thyroid gland had the lower conversion rates. The carcinoma group had the poorest conversion rate.

    They also showed that if AIT or Goitre patients take higher and higher doses of L-T4 per kg of body weight, they risk depressing their T3 levels further if they are a “poor converter.”

    Wow. The authors openly blame T4-only therapy for poor conversion status:

    “While acknowledging the role of genetically determined differences in deiodinase activity affecting conversion rates, the poor converter status described here appears to emerge mainly as a consequence of the T4 monotherapy itself, induced by the mechanisms discussed above (42, 43, 44, 45). Compared to untreated subjects, deiodinase activity and conversion efficiency tend to be diminished in L-T4 treatment (20, 22).” (p. 203)

    The authors also emphasize “the inhibitory actions of … reverse T3 (rT3) on deiodinase type 2 activity (27).” (p. 202)

    • Because deiodinase activity is governed by tsh lvl, surpressing tsh with so much t4:-) just 10% more of t4 and you get low t3 thats why people who take large t4 dose (100% )……must be getting small amounts of t3 with it…you cant have low tsh , bad thyroid and have enough t3 its impossible!….t4 above 65 mcg is supressing tsh in sick patients too much to produce enough of t3 by thyroid
      Gland itself!…but this is funny that someone did not figure that out in 2017, its all known, how much of t4 and t3 body produces, and thyroid, so dont get it that so many people still cant do 2+2

  9. I recently started taking Cytolmel for low T3. After about two months my T3 has not significantly changed, but my reverse T3 has increased markedly.
    The numbers below show a couple of years history from the current lab, but do not show other data that I have on file from several years ago when my T3 ranged from 4 to as high as 7.

    T3 Free

    2.4 pg/mL
    Date: Dec 07, 2016 04:30 p.m. PST
    Reference Range:2.0-4.4

    2.3 pg/mL
    Date: Sep 29, 2016 12:56 p.m. PDT
    Reference Range:2.3-4.2

    2.4 pg/mL
    Date: Sep 06, 2016 08:17 a.m. PDT
    Reference Range:2.3-4.2

    2.6 pg/mL
    Date: Sep 22, 2015 11:17 a.m. PDT
    Reference Range:2.3-4.2

    2.6 pg/mL
    Date: Apr 06, 2015 04:38 p.m. PDT
    Reference Range:2.3-4.2

    Reverse T3

    26.4 ng/dL
    Date: Dec 07, 2016 04:30 p.m. PST
    Reference Range:9.0-27.0

    15.4 ng/dL
    Date: Sep 06, 2016 08:17 a.m. PDT
    Reference Range:9.0-27.0


    5.32 uIU/mL (High)
    Date: Dec 07, 2016 04:30 p.m. PST
    Reference Range:0.40 uIU/mL – 5.00 uIU/mL

    5.69 uIU/mL (High)
    Date: Sep 29, 2016 12:56 p.m. PDT
    Reference Range:0.40 uIU/mL – 5.00 uIU/mL

    7.39 uIU/mL (High)
    Date: Sep 06, 2016 08:17 a.m. PDT
    Reference Range:0.40 uIU/mL – 5.00 uIU/mL

    3.15 uIU/mL
    Date: Sep 22, 2015 11:17 a.m. PDT
    Reference Range:0.40 uIU/mL – 5.00 uIU/mL
    3.53 uIU/mL
    Date: Apr 06, 2015 04:38 p.m. PDT
    Reference Range:0.40 uIU/mL – 5.00 uIU/mL

    T4 Free

    1.56 ng/dL
    Date: Dec 07, 2016 04:30 p.m. PST
    Reference Range:0.60 ng/dL – 1.60 ng/dL

    1.51 ng/dL
    Date: Sep 29, 2016 12:56 p.m. PDT
    Reference Range:0.60 ng/dL – 1.60 ng/dL

    1.38 ng/dL
    Date: Sep 06, 2016 08:17 a.m. PDT
    Reference Range:0.60 ng/dL – 1.60 ng/dL

    1.18 ng/dL
    Date: Sep 22, 2015 11:17 a.m. PDT
    Reference Range:0.60 ng/dL – 1.60 ng/dL

    1.11 ng/dL
    Date: Apr 06, 2015 04:38 p.m. PDT

      • Since Kresser’s 2011 article series appeared, this excellent 2014 article has come out: “Defending plasma T3 is a biological priority” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4699302/ In a nutshell, if you have a thyroid that is physically damaged and unable to produce enough T3 directly into your blood plasma, then your body can’t effectively “defend its plasma T3” levels at all times. Defending your plasma Free T3 levels is important because certain organs don’t have the ability to locally convert T4 to T3. You may find yourself in a health situation where your T3 is being broken down by a dysregulated enzyme at a faster rate than your thyroid gland can produce or your other enzymes can convert. The article explains that “Deiodinase type 3” is responsible for both converting T4 into Reverse T3 and deactivating Free T3 into inert T2 before it reaches your cell nucleus. It is almost always the cause of Low T3 syndrome. Normally, Deiodinase type 3 is supposed to protect your brain or a pregnant mother’s fetus from thyrotoxicosis if T4 levels go too high. But if your Deiodinase Type 3 has become oversensitive to T4 and has become overactive, it can overwhelm all your best efforts to aid your glandular T3 production or T4-T3 conversion with an excellent diet and supplements, etc. In addition to taking T3 meds to supply more direct T3, you may need to reduce or slowly eliminate your intake and/or production of T4, since T4 is the only thing that can be converted into Reverse T3. You have to take away the building blocks of Reverse T3 at the same time as giving your body the sufficient Free T3 it lacks. I did this switch from T4 to T3 and it was effective in restoring my overall health from a horrible crisis.

        • Thanks for the reference Tania. I am only taking supplemental T3, Liothyronine, not Armour or any other T4. I started two months ago on 5 mcg T3 and now I’m up to 25 mcg spread over the day. I also take iodine and selenium.
          Several years ago I was taking 25 mg per day of iodine and my T3 was between 4-6. My doc thought that might be high, so I cut back and more or less forgot about it. Recently I was advised that I should get my T3 between 4-6 to reduce coronary calcium that has been increasing for five years. Iodine didn’t increase T3 this time. It only increased my TSH. So I have resorted to T3, but the significant change has been the increase in Reverse T3. My ratio of T3:RT3 went from 15 to 9. The research indicates that a ratio of about 20 is minimal or heart disease is a risk.

          • You are taking completely crazy therapy and you will do damage to your heart and adrenal glands with that t3 therapy, read what i wrote above! Dont try to invent hot water its allready invented:-) ……i know guys who did not want to listen to me u til having heart racing every night during the sleep on same 25 t3…..no human should take that! Your thyroid makes only 3_4 mcg of t3 so you should not give more !

    • Mike, why has your FT4 increased over time? Are you on a T4 drug? That can cause your RT3 to increase. Cytomel should not increase RT3. Also, check your cortisol, vitamin D3, vitamin B12, ferritin and also check both thyroid antibodies, TPO and Antithyroglobin. Your TSH is really high long term. Check DNA for gluten issues. As Chris says, inflammation is such a contributor, and gluten, dairy and other dietary allergens can cause all your many vitamins and minerals to be unable to absorb via small bowel. When this happens, it effects the ability of thyroid hormone to work at the cellular level.

      • Lisa,
        I think my TSH is high due to iodine supplementation, but T4 has not increased. I’m taking a generic Lyothronine T3: now 25 mcg per day. My B12 tests above normal and Ferritin has been about 70. D3 about 70. We have been non-gluten diet and non dairy for several years.
        Thyroid antibodies may be a factor. I have not been tested, but I do not have hypothyroid symptoms. I exercise strenuously and work full time. At 67 years of age, I feel fine, very fit, and I’m not obese.

  10. Hi friends,

    Any advice please? I have felt awful for over a year now. Pretty much every symptom of hypothyroidism.

    In October:
    TSH 1.29
    Free T4: .87
    Free T3: 2.8

    I was concerned about low T3 levels and talked to MD. I started taking 50 MCG Levothyroxine (synthroid) 1 month ago.

    TSH: .49 (.45-4.67)
    Free T4: 1.09 (.71-1.85)
    Free T3: 2.4 (2.4-4.2)

    It bothers me that my T3 went down. I feel worse too. Could that be the cause? Is adding 5 MCG Cytomel a good course? Should I decrease my Synthroid when I add Cytomel? It seems it is doing a lot for everything but T3 levels.

    • Did they check your reverse T3? Could be adding T4 is just pushing more to rT3 and not to T3, based on your numbers. Also, did you get your thyroid antibodies tested? They may be having an impact, too.

      My doctors put me on T3 only, and I’ve done well with it, at 25-37.5 mcg a day. T4 didn’t help me. I know what Chris and some of the other folks here say, but this is what works for me.

      Have you had your adrenals checked? Also, you may want to try a gluten free diet. And be asking why your thyroid is unhappy in the first place, which is what Chris is encouraging. Likely, something is causing your hypothyroidism.

      In the short term, if it were me, I’d try adding T3 in 5mcg increments, a couple days at a time, and see if you can find some combo that works for you.

    • 50 mcgs of levo is not nearlh enough to raise your T3 your not converting you t4 into t3, I was on 100mcgs of levo and my T3 was too low. I had to start T3 alone..no more levo as it was not converting its T4 into T3, you’ll never get you levels up on that small amount of T4 which is what you are taking..My opinion

  11. Anyone interested in finding a physician open to testing and prescribing combination T4 and T3 might want to check out the website: thyroidchange.org

    This is a non-profit dedicated to improving the diagnosis and treatment of thyroid issues. I found my endo on their “find a doctor” listing who is open to adding cytomel (T3) to my synthroid (T4)…and he even accepts my insurance (BCBS PPO).

  12. So is there a treatment? I have off the charts low tt3 and higer normal rt3 but tsh and t4 is perfect. My doctor seems to think that estrogen is binding and blocking t3. We are going to try a low dose progesterone to balance the estrogen dominance. But I would love to hear if there are other effective treatments. I don’t have a chronic illness that I know of.

  13. I’ve been on levothyroxine for several years for high TSH (5.5) which is now normal, but still exhausted, achey, memory issues and 30 lbs heavier than before I took cipro 4 years ago. been to many doctors, most of whom treated me like a psych case and tried to put me on antidepressants, which I refused due to serotonin syndrome when they put me on them 8 years ago.

    my latest doc (who I can’t see anymore so I don’t know what I’ll do) just tested my T3 because the endo didn’t. started 5 mcg levothyronine in addition to the levothyroxine 3 days ago and already feeling better. night sweats gone, and today I had the sudden urge to take a walk, for no reason except the joy of moving. I’d forgotten what that felt like. I do have a bit of a headache though. don’t know if it’s related but I have to find someone who can continue my care who isn’t an idiot.

  14. Dr Evans, at Holtorf in L. A. is amazing!

    I was given the wrong ratio of meds (high at4, Low T3-bioidentical) for two years and gained 60 pounds! My doctor ignored my complaints.

    I have hypothyroidism, and can’t convert T4-T3, from a thyroid injury. I almost broke my neck surfing.

    My reverse T3, was the highest they had seen, as all the T4 converted to reverse T3

    Dr. Evans had me figured out immediately and reversed the ratio of bioidentical Meds to 25 T4, 65 T3, abd I’ve lost 52 pounds in two years without dieting.

    She’s extremely knowledgable and treats the individual.

    Most doctors are ignorant of thyroid injuries! Often they occur due to the treatment of OB Gyns when babies are born. They crank the neck and injure the thyroid. Whiplash can damage the thyroid as well.

    Injury can be a cause of low T3…

  15. My 15 year old daughter was diagnosed with Gastroparesis and SIBO. Her blood work shows low T3. I pointed this out to her GI specialist and asked him if the T3 level will rise after the bacteria in the small intestine are eradicated. He stated that there is no correlation between the SIBO and T3 level and the the low T3 was not clinically significant. In the past 8 months my daughter has lost 20 lbs, her hair is thinning and her body temp is 97. I’m just looking for any insight. I’m not convinced that the SIBO and low T3 are not related.

    • Check the book hashimotos root cause it links sink to hypothyroidism. Doctors are clueless

    • People with hashimotos which is an autoimmune disease whereby the body attacks the thyroid gland, have a higher percent than non hashimotos people with sibo. You need to get thyroid antibodies score from bloodwork tpo and tg. I have hashimotos and a low amount of thyroid antibodies but it has been enough to destroy some of my gland making me have low body temperature, cold hands and hair loss. My tsh has held at 2.5 and my t4 is good but my t3 was not in the optimal upper percent of the range. Recently the t3 fell to the lowest number on the range. Read hashimotos root cause by dr wentz. You will see food intolerances, sibo, parasites etc are the root cause of triggering an autoimmune disease like hashimotos. A leaky guy must be present as well and sibo contributes to leaky gut as do food intolerances. People with hashimotos have gluten intolerance. I stopped eating gluten and my thyroid antibody scores dropped over 10 months to now being within range. I did an Igg antibodies test and found i have extreme antibody levels to dairy and egg which means in addition to a food intolrance to gluten, i have a food intolerance to these foods When i cut out these foods my joint and muscle pains went away in 4 weeks. To fully stop these antibody attacks i need to now restore my gut and seal it. First step is to get rid of the sibo. I have done three rounds over the last year of antibotics followed by antimicrobials which has not worked to get a negative breath test My sibo breath test shows extreme for hydrogen. I am now about to start elemental diet followed by a sibo diet (siboinfo.com) that combines a prokinetic drug and iberogast prokinetic so that i do not get a recurrence once they are killed. My body will keep leaking foods and toxins into my blood causing my hashimotos to continue and put me at risk of triggering more autoimmune diseaes until i seal the gut. Eating the foods i am intolerant to and not getting rid of sibo are preventing me from sealing the gut. I have found betaine with pepsin increases the acid in my stomach and i have no bloating at the end of the day anymore. I take 6 per meal. You can look up how to test for low stomach acid. Low stomach acid and slow motility are two of the most common root causes of sibo. I take iberogast 20 drops at bed and will add in a prokinetic drug to further help my motiity. Back to my t 3 being low. I will wait and see impact on this score once i get rid of sibo. My doctor did offer natiral dessicated thyroid hormone at a very low dose but i will only take if my low thyroid symptoms of cold hands and hair shed continue after the sibo is gone

      • thank you for this input. We have since discovered that my daughter has hashimoto’s. She is scheduled for a breathe test in two weeks. We have eliminated gluten and dairy and are following a low FODMOP diet. Her diet is very limited at this point but she has done better since eliminating these trigger foods. The difficult part now is trying to get the weight that she lost back on her (25 lbs) with such a limited diet. She is determined to stay active, plays varsity field hockey. The endocrinologist we saw only said he would be willing to put her on low dose synthroid and never mentioned altering her diet. That was something we determined to do on our own after researching ways to treat low thyroid. I am hesitant to put her on Synthroid since her T4 is not low. It is her T3 that is low and from what I understand Synthroid only replaces T4 which her body in turn needs to convert to T3. He was not convinced that it was her thyroid causing her issues since most patients that have hashimoto’s gain weight, not lose it. I mentioned that I felt it was due to her slowed motility and her gastroparesis which were potentially caused by the hashimoto’s. He said he had never come across that before.

        Sorry to ramble on so much it’s just that I feel I have really started to put the pieces of this puzzle together and yet the doctors don’t seem open to the Hashimoto’s,SIBO, weight loss connection. Thank you for sharing your experience and best of luck with treating the SIBO.

  16. I was diagnosed with having low T3 (but nothing else) in April of this year. I have been taking 5 MCG of Liothyronine 2 times a day since then. I have seen some improvements in my peripheral neuropathy. My feet, specifically my toes used to burn and turn bright red if they got too hot. I could not go out in the sun, in a hot tub, or even get my heart rate up through exercise without having my feet go up in flames and my hands get really hot. I do still have the peripheral neuropathy as well as neuropathic pain in other parts of my body, but it is not as severe. In recent months, however, the pain when walking has increased as well as pain in my lower back and hips. No doctor has ever mentioned low t3 syndrome. I am still looking for answers and would love to know if anyone else has found anything to help.

    • Did you take cipro, levaquin, avelox antibiotics? I had burning too from the peripheral neuropathy, which was from those antibiotics. Thyroid went bonkers after first dose of levaquin. Feet burning has subsided but did a lot of things that helped, like sun chlorella and magnesium citrate, and magnesium threonate, both powdered to avoid fillers.

      • I didn’t take any medication during the time when the burning started.
        I took Gabapentin and Cymbalta to help with the burning, but it didn’t go away until I started taking Liothyronine. Unfortunately, it feels like it is starting to come back again. My doctor is testing for a vitamin D deficiency and having me start Alpha Lipoic Acid R. Has something worked really well for you in regards to the burning? I haven’t found anyone else who has had this symptom.

        • I was given those antibiotics months before the burning. Some people get the burning and neuropathy right away, some many months later. regardless, the most common thing to help has been magnesium, usually citrate. Alpha lipoic acid has also helped some. A good quality vitamin c ( powdered, if possible), resveratrol. Although I still have neuropathy, the burning has stopped. If I were you, I would check my medical records for at least a year prior to the neuropathy/foot burning to see what medications were prescribed. If it turns out you were prescribed any fluoroquinalones, I can recommend a Facebook group where the members have narrowed down things that help. Good luck

  17. I waa just researching T3 because after 5 yrs on Armour my doc changed me to Tyrosint. No T3. After a month, I have a brain fog and cannot put sentences together. My research found that if you do not have the binding proteins available then your body cannot convert T4 to T3. One thing that caught my attention was D3. I have low vit D even though I supplement 50,000 to 100, 000 ius weekly. I also have osteoporosis and autoimmunity. Chances are Vit D plays a significant role in the T3 problem too. Any one know more Vit D defiency and Low T3?

  18. Help!
    I am at my wits end almost suicidal. I am 70 now but when I was 16 I had a goiter removed (my grandmother died of this)
    They said they took too much out and I have been on thyroid replacement medicine (All my Life). So it has been a journey for me and I am still a basket case with NO help from any DR.
    Now I am gaining weight at a high speed, very depressed (told my Dr that and he wanted to give me pills), DO NOT SLEEP at night, constipated, bloating, puffy eyes, hardly any eyebrows, now skin problems.
    I cannot take it anymore and I am tired and unhappy, miserable and put my poor husband through so much, he cries because he cannot help me and he has seen my life go through HELL for the past 45 years we have been married all due to my thyroid.
    Is there ANYONE out there that can help me?

    • Please don’t despair! You are not the only one. I am finally starting to get some sleep with a combination of de-stressing, inositol, tryptophan, melatonin, magnesium, TMG, phosphatidyl serine, magnolia bark (the last two for high cortisol) – and my doctor actually supports me taking all these things! Everyone is different, but I pray that you can find a good functional medicine or holistic doctor lines who will take the time to get to the bottom of things and figure out what you need for your thyroid. Good doctors are out there, it just takes a little searching. And all the suggestions about an auto-immune and anti-inflammatory diet really do help. It’s a lot of work, but I have seen a difference with it. God bless you!

    • Collen. Please call dr. Edward Pearson at the New Medicine Foundation in Jupiter, FL. This man is a brilliant chemist when it comes to thyroid numbers and levels. You don’t have to suffer. I have sent so many people there and they ALL get better. Including myself when I thought there was no hope. I will be praying for you.

    • Dear Colleen, I have been on T4 only (synthroid or levoxyl) for 20 years after radioactive iodine treatment from Graves Disease. For much of these 20 years I have felt horrible. One month ago, I tested low in free T3 and convinced my doctor to add 5mcg of cytomel. OMG…such a small change is increasing my energy and changing my life! Don’t give up! Find a doctor…such as a functional medicine doc…who believes in the importance of both T4 AND T3! Hugs and best wishes, Caryn

  19. Thank you for this insightful article. I have been using T3 hormone replacement for 5 months now (under supervision of my dr) – he velieves I have Wilsons syndrome – I have been following the protocol for this – he starts me off with a dose of 7.5 gradually making my way up to 97.5 – and then I stay there for about 10 days then we gradually come down again. Simce taking this – which was suppose to make me feel and look better – I have only gained weight amd have extrme water retention. All my clothes that used to fit perfectly is now too small and so tight. I feel amd look awful. My skin is also bad. I also have a vit D deficiency and am taking vit D oil for this. I am so frustrated as I am eating a 100% clean diet almost entirely whole foods. I do yoga daily and exercise regularly. I am a 25 year old female, way around 75kg and im 6.5m – ie arounf 15kg overweight. I am tired of being overweight and having bad skin. I dont know what to do anymore and I have been to several doctors. I dont know who to trust anymore. Any advice would be helpful.

    • Alesha,

      Sounds like you need to stay at a particular dose for a while, 6-8 weeks. I’m in the USA so we use mcg as a measurement. So, perhaps 60 mcg 3x a day for 6-8 weeks. Make sure to take a daily vitamin, Iron and Folate/ Folic acid EVERYDAY while you are on T3.

    • From what I read, when you’re in that protocol, you will get worse before you get better. Do what your doctor asks you.

  20. I have recently, fallen into a deep depression. The realization that after fighting whatever is wrong with me for 13 years, the only relief I ever got, and the best I ever felt was from taking CYTOMEL which is T-3.

    I do not understand why a doctor cannot work with me long enough to see if that works again. I am at the point of complete despair. I have spent $$ Over and over for Drs, Naturopaths, Blood Tests, and Appointment Fees to no avail. Now I fell there is absolutely NO HOPE for me.