The Thyroid and Thyroid Hormones

match on fire

match on fire

The thyroid is a small gland that lies in the neck about the level of the Adam’s apple and weighs approximately one ounce.  It produces thyroid hormone and calcitonin.  The parathyroid glands are very small and lie on the outside portion of the thyroid gland and secrete parathyroid hormone.  Thyroid hormone ignites your metabolism so you can burn fat and produce energy.  We will be focusing on thyroid hormone.

The thyroid gland is stimulated to make thyroid hormone by thyroid-stimulating hormone (TSH) which is produced in the pituitary gland located in the brain.  The pituitary is controlled by the hypothalamus in the brain which monitors the amount of circulating thyroid hormone.  Iodine must enter the thyroid gland through a transport system that is repaired with the intake of vitamin C.  There is usually about 20-30 mg of iodine in the body and 75 percent of it is stored in the thyroid.  In addition to iodine, magnesium, zinc, copper, and vitamins B2, B3, and B6 are required for thyroid hormone production.

The thyroid gland produces two thyroid hormones: T4 (thyroxine) and T3 (triiodothyronine).  Ninety-five percent of thyroid hormone produced is T4 and five percent is T3.  T3 is the active form of thyroid hormone which is produced as a result of one iodine being cleaved from T4.  T4 is inactive so the majority of thyroid hormone produced is actually inactive.  The numbers “3” and “4” indicate the number of iodines.  This is key in understanding optimal thyroid function.  Both T4 and T3 are bound to proteins in the blood until they reach your cells and become unbound to work their magic on metabolism.

Most of the T4 is converted into T3 in the liver.  Approximately sixty percent of the T4 is converted into T3, twenty percent is converted into an inactive form of thyroid hormone known as reverse T3 (irreversible), and the remaining twenty percent is converted into T3S (T3 sulfate) and T3AC (triiodothyroacetic acid).

Conversion of T4 hormone

Reverse T3 can be problematic; even though it is inactive, it will still bind to T3 receptors and block T3 from binding and working its magic on metabolism.  Too much or too little cortisol that is produced by the adrenal glands will increase circulating levels of reverse T3.  This mechanism is due to suppressed liver detoxification and clearance of reverse T3 from excess cortisol production.  Stress can not only cause signs of hypothyroidism but it will also impair the liver’s ability to detoxify.  Cortisol will also suppress TSH production resulting in low thyroid function.  Immune system activation, high adrenaline, excess free radicals, aging, fasting, stress, prolonged illness, and diabetes will also drive the inactivation of T3 to reverse T3.

Reverse T3

T3 and reverse T3 can also be inactivated by conversion into a hormone known as T2.  Elevated insulin levels due to a diet high in refined carbohydrates will also increase reverse T3 levels.  Toxic metals including mercury, cadmium and lead will also increase reverse T3 production.  T3S and T3AC are inactive until they are catalyzed by an enzyme in the GI tract known as sulfatase.  This enzyme is dependent on healthy gut bacteria.  We will discuss in a later chapter the importance of a healthy digestive tract as it relates to twenty percent of active thyroid hormone.

Thyroid hormone’s main role is to control metabolism (energy production) inside the cell.  Our cells contain tiny factories called mitochondria that produce energy from fat, sugar and protein.  Thyroid hormone controls the function of the mitochondria which determines how much energy is produced.  Symptoms of low thyroid function are related to a decrease in energy production including:

  • Fatigue
  • Weight gain/inability to lose weight
  • Constipation
  • Dry/itchy skin
  • Dry brittle hair and nails
  • Depression
  • Headaches
  • Overly sensitive to cold
  • Cold/numb hands and feet
  • Muscle cramps
  • Depressed immune system–can’t recover from infections
  • Slow wound healing
  • Unrefreshing sleep
  • Digestive problems due to low stomach acid
  • Hair falls out
  • Water retention
  • Lateral third of eyebrow thinning

Thyroid-Stimulating Hormone (TSH)

Traditional medicine relies mainly on the TSH or thyroid-stimulating hormone blood  test to measure thyroid function.  TSH is not a thyroid hormone.  TSH is produced by the pituitary based on how much thyroid hormone is circulating in the bloodstream.  As thyroid hormone levels drop, TSH production will increase to stimulate the thyroid to make more hormone.  If thyroid hormone increases, then TSH production will decrease because the thyroid is making plenty of hormone.  The TSH alone is not adequate to assess thyroid function because it doesn’t take into consideration the conversion of thyroid hormone into its active form which occurs in the liver, kidneys and lungs.  The TSH test also does not take into account thyroid hormone receptor resistance.  Thyroid hormone receptors can become resistant to thyroid hormone due to thyroid-disrupting chemical exposure leading to normal blood tests but development of low thyroid symptoms.  Cortisol produced during stress by the adrenal gland can also inhibit TSH production further throwing off the accuracy of the test.  If the TSH is elevated, the traditional physician will prescribe synthetic T4 and this will usually reduce TSH into the “normal” range.  This approach does not take into account peripheral thyroid hormone conversion or receptor binding.  If the body is compromised in its ability to activate thyroid hormone into T3, then taking T4 will result in a failure of treatment.  If the adrenal glands are out of balance, then most likely thyroid hormone function will also be out of balance.  In addition, if thyroid hormone receptors are desensitized, this approach will fail as well.

You will find that most medical physicians do not spend much time reading the peer-reviewed medical literature which provides us with valuable data on TSH levels.  An excellent study was published by Obal and Krueger (2001) on sleep deprivation and thyroid hormone production.  The researchers concluded:  “When sleep deprivation is maintained for weeks, the plasma concentrations of T4 and particularly T3 decline but TSH remains normal.”6  Do physicians ask you about your sleep patterns?  Perhaps this could be the reason for the abnormal TSH.  I have seen many patients who also suffer from insomnia and sleep problems and present with low thyroid symptoms and abnormal TSH levels.  Does this mean they should have thyroid hormone dumped into their bodies?  Unfortunately, this happens to many people.  I always take into account every patient’s sleep pattern and correct it as part of our treatment plan.  Many times, sleep patterns are abnormal due to blood sugar and adrenal gland imbalances.  Remember, you are not a lab test but a beautiful, complex being where everything is connected as one.

Testing & Diagnosis

Blood tests alone cannot always adequately diagnose thyroid hormone imbalance.  It is estimated that about forty percent of the U.S. population suffers from some kind of thyroid imbalance as opposed to the current traditional figure of ten percent.  This is due to the inadequacies of the TSH test.  In addition to blood testing, I review a thorough case history and a number of detailed health questionnaires and also perform a comprehensive physical examination for clues to thyroid hormone imbalance.  Basal body temperature testing is used by many practitioners to evaluate thyroid function but this does not solely indicate a thyroid imbalance.  There are many other factors that can cause a low basal body temperature such as adrenal fatigue, leaky gut, impaired liver detoxification and malnutrition.  I use the basal body temperature simply as one more diagnostic tool to evaluate the overall picture of a patient.  Another sign that may indicate low thyroid function is thinning of the lateral one-third of the eyebrow.

The following thyroid tests can provide more information about your thyroid.  Use this as a guide when you get the results of your blood tests:

  • TSH (Thyrotropin) – Thyroid-stimulating hormone is produced by the pituitary to stimulate the thyroid to make hormone.  The ideal range is debatable.  Traditional medicine uses a much broader range of about 0.5-4.5.  This range misses many hypothyroid patients such as those with a TSH between 1.5-4.5.
  • Total Thyroxine (T4) – This test measures the amount of T4 (thyroxine) that is both bound to protein and unbound.
  • Free Thyroxine Index – This is calculated by multiplying the TT4 by the T3 uptake.  The result gives you the amount of unbound T4 or Free T4.
  • Free Thyroxine (Free T4) – This measures the amount of unbound or free T4 which is the most active form.  Free T4 is not affected by medications or other factors that affect protein bound thyroxine (TT4).
  • T3 Uptake – A measurement of the amount of available binding sites for free T3 on thyroxine-binding proteins.  Elevated testosterone will reduce the number of binding sites and cause a low T4 and high T3 uptake.  Excess estrogen from hormone replacement or birth control pills will increase binding sites and can cause high T4 and low T3 uptake.
  • Free Triiodothyronine (Free T3) – This is a measure of free T3 levels or unbound T3.  This is the best test if your natural physician wants to see the amount of available active thyroid hormone in the bloodstream.
  • Reverse T3 (rT3) – This is a measurement of the amount of T3 that has been inactivated.
  • Thyroid Antibodies – Thyroid peroxidase, thyroid-stimulating immunoglobulin and antithyroglobulin elevations indicate autoimmune thyroid disease such as Hashimoto’s or Graves’ disease.  Thyroglobulin and calcitonin are mainly used in the diagnosis of more serious thyroid diseases such as cancer.

Prescription Medications

Prescription medications do not take into account underlying physiological imbalances and may lead to dependence on the medication.  The following drugs are prescribed by physicians to treat the thyroid:

  • Synthroid – Synthetic thyroxine (T4).  Synthroid is the most popular prescription drug for hypothyroidism.  Synthroid is in the top five most commonly prescribed drugs in the US.  Synthroid can be converted incorrectly into inactive reverse T3 resulting in no symptom improvement.
  • Levoxyl – Synthetic thyroxine (T4).
  • Levothroid –  Synthetic thyroxine (T4).
  • Levothyroxine – Synthetic thyroxine (T4).
  • Thyrolar – Synthetic T4 and T3.
  • Cytomel – Synthetic T3.  Many side effects including hyperthyroid symptoms.
  • Armour Thyroid, Nature Thyroid, Westhroid – Natural thyroid hormone from desiccated pig thyroid tissue.  Contains approximately 38 micrograms/grain of T4 and 9 micrograms of T3/grain as well as other cofactors for thyroid hormone production.  Nature Thyroid is a better choice than Armour because it does not contain corn and other binders.

Many alternative-minded medical doctors prescribe Armour and other natural dessicated pig thyroid tissue.  This is a better option in some cases than merely prescribing synthetic T4 (Synthroid) because these natural agents also contain T3.  The problem with Armour is that it contains corn and other fillers which can be a problem for those with specific sensitivities.  Nature Thyroid is the best choice because it doesn’t contain corn or fillers.

Another issue with such treatment methods is suppression of hypothalamic-pituitary-thyroid feedback mechanisms.  Whenever you take a hormone that is produced in the body, this tells the brain that it no longer needs to stimulate hormone production because it is constantly being ingested.  When male bodybuilders take testosterone, their testicles shrink because there is no longer a need for them to make testosterone.  Taking thyroid hormone for long periods of time will suppress natural production which may or may not return after discontinuing the medication.  It is strongly encouraged that you do everything possible to normalize thyroid function.  Americans typically want a quick fix, a magic pill that will instantly give relief.  Many people get this instant relief from medication but the long-term effects of dependency and suppression of natural hormone production may not be worth it.    Patients who have had their thyroid removed or partially removed may require prescription thyroid hormone.  If the gland is not present then thyroid hormone must be replaced.  In this case, prescriptions such as Armour and Nature Thyroid are the better choice.

Conversion of T4 into T3

T3 is much more active than T4 and is responsible for most of the actions of thyroid hormone on the cell.  Some people cannot convert T4 into T3 as efficiently as others.  In addition, there are many factors that could be inhibiting this process.

Selenium, antioxidants, iron, magnesium, zinc, vitamin A, vitamin B6 and B12 deficiencies can lead to poor conversion.  The medications listed above affect thyroid hormone conversion as well as production and receptor binding.  As people get older, they lose their ability to convert thyroid hormone which may be due to decreased vitamin and mineral absorption.  This is due to a loss of intestinal barrier function where all of your nutrition is absorbed.  This barrier loses its function as we age so supplementation is absolutely necessary.  Excess estrogen from xenoestrogens in the environment, birth control pills and hormone replacement can lead to low thyroid symptoms.  Estrogen increases the protein that binds to thyroid hormone leaving excess thyroid hormone bound to protein which is inactive until it becomes unbound.  Cortisol produced by the adrenal gland is a major factor in converting thyroid hormone.  Too much cortisol can inhibit the activation of thyroid hormone and too little cortisol yields the same result.  Exhausted adrenals will cause low thyroid symptoms due to the lack of cortisol production.  Insulin is a hormone released by the pancreas to handle blood sugar elevations after consumption of carbohydrates and can inhibit hormone conversion as well.  Soy products have been shown to inhibit the conversion of thyroid hormone.  This only goes for soy products that are non-fermented.  Fermented soy products such as miso and tempeh are okay.

Vitamin C has been shown to enhance the conversion of thyroid hormone.  Radiation, chemotherapy, growth hormone deficiency, and cigarette smoke have also been shown to reduce thyroid hormone conversion.

So as you can see, there is a lot more to the thyroid than just the TSH test.  I recommend to at least get TSH, Free T4 and Free T3 done.  And I will usually add in reverse T3 if excessive stress seems to be an issue for the patient.  Additional tests that can provide clues include leptin, sex hormone binding globulin, and a cholesterol panel.  All of these may be high when a patient is hypothyroid.

I’ll also look at a urinary adrenal profile to evaluate metabolized cortisol which is low in hypothyroidism and high in hyperthyroidism.

Make sure you have been thoroughly evaluated before making any decisions about treatment for your thyroid and definitely don’t just rely on a TSH test.  I hope you have a better understanding now of the thyroid and thyroid hormones.

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65 Responses to The Thyroid and Thyroid Hormones

  1. Gail Davis February 13, 2012 at 8:44 am #

    Should my synthroid dosage be increased? My TSH is 3.972, T4 is 5.9, and my T3 uptake is 37.4 (hgh). I have symptoms of hypothyroid again. Fatigue, itchy dry skin, cramping and cold feet and hands etc. My body temp is always low, but doctors don't think it is important.  

  2. Nikolas Hedberg, D.C., D.A.B.C.I. February 13, 2012 at 8:00 pm #

    Sorry to hear about your health problems. We cannot give medical advice on our website. Please consult with your MD.

  3. sharon August 31, 2012 at 5:56 pm #

    My doctor tested my T3, I had a 3.0. He wants to put me on cytomel for low thyroid. The lab said between 2.3 and 4.2 was the normal range, which would put me near the middle of normal. When I asked my doctor about this he said, he doesn’t think those ranges are accurate, he thinks they should be in between 3.0 and 5.0. Is this normal to have a differing range of normal? If not what is the normal range? Also he said a reverse T3 test would be more accurate in telling how much T3 I should have, but he thinks it’s a waste of money, that I should just go on the medication. Any thoughts?

  4. James R September 7, 2012 at 6:00 pm #

    What are the consequences of taking thyroid medication (Armour) and a low cortisol level. Does the Armour just accumalate? If your cortisol is up to speed does the dosage of thyroid med change?

  5. Nikolas Hedberg, D.C., D.A.B.C.I. September 8, 2012 at 8:57 am #

    The answer is very patient specific. Too many factors to account for for a definitive answer.

  6. Claire Cohen November 11, 2012 at 11:20 pm #

    I have an 11 yr old daughter who consistently has low T4 and Low T4,Free. TSH is considered in range at 2 different labs with a report of 1.330. Thyroid Binding Globulin is 16.3 (lab in range is 13-30). T3 is also in range at 146. The conclusion is that she has low binding protein for thyroid hormone.
    Current concerns:
    skin gets so dry it flakes off in sheets on her face
    fatigues easily
    sleeps 12 hrs at night but is not well rested when awake
    cold flashes that disrupt schooling / heat flashes at night
    severe, consistent headaches (clear MRI and CT scan)
    although not considered overweight, she is at the 84th %ile which can not be explained away due to well balance diet and more physical activity than most girls her age – swim, rock climbing, roller skating, tennis, walking, etc.
    lack of ‘umph’ – despite 3 years on a swim team her muscles do not seem to be able to go any faster then where she was 3 yrs ago, over all weakened muscle tone, unable to open many water bottles, can not do monkey bars, etc.
    The ‘specialists’ only seem able to be able to treat the paper the reports are printed on and not the people sitting in front of them.
    At this point do I need a second opinion, and what type of doctor should I go to?

  7. Squishyleo November 24, 2012 at 2:23 pm #

    If someone had a high cortisol condition such as Cushing’s, that could produce hypothyroid effects, according to this, which would probably be detected before the Cushing’s that caused it. How would the standard treatment of throwing T4 at the problem effect the underlying cortisol condition? How would signs and symptoms present in that case?

  8. Nikolas Hedberg, D.C., D.A.B.C.I. November 25, 2012 at 10:33 am #

    There are many variables that can come into play around the scenario here.

  9. BKUSAF83 January 4, 2013 at 10:34 pm #

    What are the symptoms of high T3 Uptake?

  10. Nikolas Hedberg, D.C., D.A.B.C.I. January 5, 2013 at 10:05 am #

    Usually those with high T3 uptake have insulin resistance (blood sugar issues), excess testosterone and Polycystic Ovarian Syndrome. The excess androgens can cause hair loss, oily skin, facial hair growth, mood swings, abnormal menstrual cycles etc.

  11. Sharon January 13, 2013 at 4:39 pm #

    A friend of mine told me that if one takes too much of t3 (i.e. Cytomel), that it can affect or drop your t4 lower. Let’s say you were taking 75 mcg of Synthroid, and your last results was 1.34 (just an example), and if too much t3 is taken that it can push down your t4 to .99 (just an example), even if still taking the same amount of Synthroid (75 mcg). Is that true? Thanks.

  12. Nikolas Hedberg, D.C., D.A.B.C.I. January 14, 2013 at 11:17 am #

    Thank you for the comment but I can’t comment on questions related to medication. This should be directed to the prescribing physician.

  13. Susan January 23, 2013 at 7:41 pm #

    Thyroxine T4 free: 0.86 ng/dL;
    TSH: 5.150 H uIU/mL;
    TPO: High (didn’t see actual #s).

    Doc wants me on Synthroid as he is anticipating severe hypothyroid symptoms in the future.
    My symptoms are dry skin, brittle nails, cold extremities, weight gain (though not overweight), some muscle and joint pain.
    My older sister has hypothyroidism and is on thyroid medication.
    I consume soy in the form of soy milk and soy “butter”, and I take Yaz to help control mood swings and menstrual cramps.
    I’m thinking about discontinuing soy and Yaz and re-testing in 3 months.
    I don’t like the idea of being on more meds for the rest of my life.
    I am already taking asthma and allergy medicine daily.
    Your thoughts and suggestions appreciated.

  14. Amy January 29, 2013 at 10:03 pm #

    I was having palpitations and anxiety and in an emergency room my T3 and T4 were around 15.2, but my TSH was normal, .9, I believe. I learned that small discrepancy could cause those symptoms. However, I saw an endocrinologist who put all the emphasis on the TSH and said it was definitely not hyperthyroid, and that the elevation in the T3 and T4 were due to elevated estrogen in women. He explained the protein bound and what the “free” T4 were. But I’m still not certain about this. If it is normal for women to have higher free T4 and T3 due to estrogen, why is that not considered the “normal range” for women? This was a highly acclaimed endocrinologist, so perhaps I’m foolish to question, but I am very curious. I would like to know if there is some controversy over the TSH having to be altered and being the true test.

  15. Nichole February 6, 2013 at 9:33 am #

    I know that smoking can decrease levels of TSH. I have many of the symptoms of hypothyroidism like hair loss, fatigue, weight gain, and I’m always cold. I have been a smoker for the last year (I’m planning to quit this month). I was just wondering how much smoking lowers TSH and how long after quitting does it take to normalize?

  16. steven scholtz February 7, 2013 at 10:51 am #

    Dr. Hedberg my wife has been dealing with hypothyroid for 20 years and over the last 4 years she gets to the point of narcolepsy episodes cant even do the simplest of task her recent results showed very low t3 she was put on armor 30 for 2 weeks this past week she was still falling asleep everywhere moving slugishly and her test 2 days ago showed low cortisol as well. What tests should we be sure the doctor runs and is there a light at the end of thetunnel she is an awesome lady and mother. We need your help. She sees an actualy endo on the 20th. thank you for your time

  17. Steve Meredith February 8, 2013 at 1:05 pm #

    Along with Hashimoto’s, I had a nodule on my Thyroid and had a total removal about 6 months ago. My Dr. has me on 100mcg of Synthroid, I believe based solely on a “normal” level of TSH, however I feel as if I may still be sympomatic. With this, would I still have free and total T4, T3, and perhaps more importantly, reverse T3 levels that could be checked?

  18. Kathleen February 25, 2013 at 5:59 pm #

    I had my thyroid removed in 2005 and have been on Synthroid 100 mcg to 125 mcg ever since. Recently, I managed to convince a doctor to test me for reverse T3, and my ratio (13) showed reverse T3 dominance. That doctor says she is not skilled to treat me, however. My research indicates that I need to go on high levels of Cytomel, but I can’t find a doctor to prescribe for me. If I came to see you, Dr. Hedberg, do you have a way to treat RT3? I know you cannot prescribe drugs. Saliva tests show I have high cortisol. I also have diabetes and have some heart damage due to a silent heart attack. THANKS.

  19. Nikolas Hedberg, D.C., D.A.B.C.I. February 26, 2013 at 1:35 pm #

    Yes, I do work with rT3 imbalances. Thanks for the post.

  20. Kristen March 12, 2013 at 10:46 am #

    I am taking 2 grains of armour per day and my levels are a suppressed TSH (.01) and mid range T4 and T3. Every time I up my dose a half grain, my weight loss begins again after having stalled. I would like to see my T3 levels higher, but when I suggest adding a T3 only med like Cytomel, my doctor says it would continue to suppress my TSH and she doesn’t want to see it go any lower. Is this true, that Cytomel would continue to suppress the TSH. Do you have a suggestion as to why my weight would continue to drop after each rise in dosage? Thanks for your help.

  21. Nikolas Hedberg, D.C., D.A.B.C.I. March 12, 2013 at 11:18 am #

    Thank you for the comments but I can’t give advice on the internet.

  22. Nick March 12, 2013 at 10:20 pm #

    Hi Doc,

    If you have silent thyroiditis (inflammation of the thyroid) and you are hyperthyroid for a period of time, how long does it take your body to break down thyroid hormone?As in, how long does T3 and T4 stay in your blood if your body suddenly stops producing thyroid hormone? Does it take days or weeks to cycle out of your blood? I can’t find the answer anywhere on the net.


  23. Nikolas Hedberg, D.C., D.A.B.C.I. March 13, 2013 at 9:28 am #

    Thanks for the comment. I don’t know the exact answer to this question since it depends on the individual.

  24. anita May 12, 2013 at 9:33 am #

    good article and explanation. In Canada we can’t even get tested for Reverse T3 as it has been taken off lab offerings! 3 times my doctor orderered it , and it wasn’t done, 1 year later, we find out this test was discontinued as of 2009! I believe my problem with low thyroid started with many years of low ferritin, low vitamin D, high stress, and overtraining. Then Menopause hit me like a ton of bricks and I completely fell apart. Severe hormone deficiency (zero Progesterone, zero Testosterone, low estrogen, but sky high dheas. Adrenal dysfunction. getting better with Adrenal support (herbal from Naturopath) and on bio identicals. now we will address Thyroid, but in Canada a Naturopath cannot prescribe these meds, so we have to convince the doctor I need them despite normal labs. Still freezing and tired, gained 34 lbs in 5 months despite clean eating. my TSH has been climbing steadily and because its still in the normal range, and have low T3 and GP refuses to treat, rather she “wrote me off” as Chronic fatigue!, and the Endo she sent me to refused to even test me and precribed anti depressants which I refused. what a load of Bunk! next week I will be starting a trial of either time release T3 or NDT thanks to the co-operation of the Naturopath and a great Bio hormone doctor. the regular doctors want to keep me sick as far as I’m concerned!

  25. Indrish Chandra May 28, 2013 at 9:28 am #

    Very good article and educative. Please further improve by adding food items which will help patient in improving hypo/hyper thyrodism
    Why the following test are required and what does there result means if both are high in limits.

  26. Lindsay June 6, 2013 at 3:47 pm #

    Great article. It’s hard to find such information well written and easier to understand. I have high cortisol, panic attacks, that came on gradually after I stopped breastfeeding and some stress going on. While the only concern is that my TSH is 6, and I also know my adrenal glands are over stimulated. Is it possible that an elevated TSH can cause me high adrenaline or is the other way around is a stress reaction causing the excess adrenaline making my TSH elevated. This has been going on for 3 years. Naturopath is having me supplement me with Evening primrose (I cycle) fish oil, probiotic, b complex, magnesium, zinc,ashwaghana, rhodiola,holy basil, vitex, because my hormones are messed up. I felt great pregnant and while breastfeeding. I consume coconut oil.I eat great. I am making progress, but wondering if I should treat the thyroid with natural thyroid med. or just wait and see…

  27. Jason July 3, 2013 at 1:08 pm #

    Good article. Question: My N.D. has almost gotten my thyroid optimized with NDT.. probably another 1 or 2 blood tests should confirm.

    Also my testoserone is extremel low (300, range goes up to 1200).

    He has prescribed me bio-id testosterone restoration

    I am hesitant to take it until my thyroid is more reliable. In your experience, does a non-optimized thyroid affect testosterone levels?

  28. Nikolas Hedberg, D.C., D.A.B.C.I. July 3, 2013 at 2:26 pm #

    Low thyroid function can certainly affect testosterone levels.

  29. Jaiele Goldszmidt November 18, 2013 at 2:22 pm #

    Excellent information Dr Hedberg thanks!! It´s a pity that I do not live in the US to get my treatment whit you… Do you know any Dr in Israel that can have your exactly integral approach?
    Best regards

  30. Gordon Brown January 4, 2014 at 4:38 am #

    The thyroid gland does not produce t3, this is misleading. The liver converts t4 to t3, and if patients have liver issues then a lot of their health problems can be addressed by addressing liver function.

  31. Nikolas Hedberg, D.C., D.A.B.C.I. January 4, 2014 at 9:38 am #

    The thyroid gland does in fact produce T3. Approximately 5-7% of thyroid hormone made in the gland to be more precise.

  32. Adam January 21, 2014 at 8:33 am #


    I am a 32 year old male and after 2 years with Synthroid (0.137 mg), I asked my doctor to change for dessicated thyroid (Thyroid ERFA) because I was still tired and I had mood problems (normal tsh , t4 , t3). I have started with with Thyroid 60 mg (2 weeks) and increase to 90 mg (recommanded by pharmacist and MD).

    The first few days that I have used Thyroid, I have started having erectile dysfunction (weak erection, difficulty to maintain erection). I never had problems like this in my life, (with or without Synthroid). I have not changed anything else in my life, except Thyroid ERFA.

    I feel better on dessicated thyroid (happiest, more energy) but erectile dysfunction is a major problem. I have talked to my MD and I am back on Synthroid. I have used Thyroid ERFA for 4 weeks and I had erectile dysfunction all the time.

    Does someone has already had erectile dysfunction with Thyroid (ERFA) or another desiccated thyroid?

    Thank you

  33. Nikolas Hedberg, D.C., D.A.B.C.I. January 21, 2014 at 8:37 am #

    There can be a connection between thyroid hormone and erectile dysfunction due to it’s affects on sex hormone metabolism such as testosterone and estrogen.

  34. manon July 4, 2014 at 4:00 pm #

    I have been taking desiccated thyroid for more than 6 months now. Also taking zinc, selenium, vit B complex; HCL supplement, pancreatic enzymes; was taking Iodine (Iodoral) but stopped it; am gluten and dairy free. My TSH was elevated and now it is within range, according to my last test a few weeks ago. The thing is, I am still loosing my hair like crazy and my body temperature is always borderline. So, if my T4 is not converting into T3, what more can I do about it? I have candida (trying not to eat sugar). How do I know if it’s the adrenals, the liver or the gut that is causing this (or all the above)? I seem to be doing what every book is telling to do…

  35. g.bharathi July 21, 2014 at 5:52 am #

    report t3=146.8
    tsh=10.40 out of range

  36. Peter Todd August 9, 2014 at 10:53 pm #

    Thanks for the explanation in layman’s terms. I have been researching T3 for the last 3 years as I was a participant in a pediatric drug trail for weight loss 45 years ago. I had vast quantities of T3 and amphetamines pumped into me between the ages of 7-11. I feel there have been huge adverse reactions.

  37. Nikolas Hedberg, D.C., D.A.B.C.I. August 10, 2014 at 10:37 am #

    Thank you for your comments Peter.

  38. ted September 22, 2014 at 12:42 pm #

    Hello,Great posting. Maybe not an easy question, but does high normal, free T3 levels reduce T4 to T3 conversion?
    Or the other way to ask, can we take too much T3? but not become hyper, just reduce the conversion process.?

  39. JBall October 6, 2014 at 2:08 pm #

    My daughter was born without a thyroid (sublingual). Are the parathyroid glands attached to the thyroid gland or do they develop separately? Basically, can you still have parathyroid gland even if you never had a thyroid?

  40. Robert B. November 26, 2014 at 1:29 pm #

    I have been told thru blood test that my TSH is low, and my T4 free is high. I also suffer from erectile dysfunction. Could these both be tied in together. Also I have been taking the over 50 multiple vitamins, and Q10, and the amino acid L-Arginine, along with B2, B12 extra C, Magnesium, and D3, and MACA, to help with my ED. Could this have caused some of the problems I have now..

  41. Debbie January 26, 2015 at 7:27 am #

    Is there a reason a person would have a low t3-uptake and a low normal t4?

  42. Dr. Nikolas Hedberg January 26, 2015 at 9:42 am #

    Low T3 uptake may be caused by excess estrogen levels. Estrogen can build up if the thyroid is low, excessive bodyfat, poor digestive function, birth control pills, hormone replacement or if there is some type of genetic polymorphism with estrogen metabolism.

  43. Kirsten January 30, 2015 at 12:01 am #

    I had a baby 8 months ago, take 112mcg synthroid for past 5 months. In November TSH was .6 and T4 was 2.7, now in January TSH is 1.01 and T4 2.7. Could progesterone only birth control be effect my thyroid?

    What other causes are there?

  44. Donita March 7, 2015 at 10:29 am #

    I have several nodules in my thyroid, found by ultrasound. My tests show TSH of .314 (low),T3 FREE 3.8 (high) and T4 Total 5.5 That is all the blood tests that I have had. I am scheduled for a thyroid scan soon. I had been taking magnesium supplements (on my own), and added lots of nuts and avocadoes to my diet after the first of the year. I have stopped taking magnesium recently since it wasn’t helping with my muscle aches. Could I have inadvertently caused some damage to my thyroid?

  45. Joni March 26, 2015 at 10:05 am #

    My Dr. called said I had a thyroid level of .01, I have to go back for a thyroid panel. I am overweight, 51 years old. I was told by another Dr. I had a significant amount of reverse T3. I am so confused. Is this a hyper or hypo reading?

  46. norma May 7, 2015 at 12:56 pm #

    I would like to schedule apt.with you for daughter and me who both have hypothyroidism.where are you located?

  47. Dr. Nikolas Hedberg May 13, 2015 at 6:25 pm #

    We are located in Asheville, NC. You can contact my office at 828-254-4024 for details. Looking forward to working with you.

  48. Gerben June 4, 2015 at 8:08 pm #

    In your experience with successful treatments of patients with primary hypothyroidism (not Hashimotos etc), have you found that all symptoms – and specifically cold sensitivity – are fully relieved or even resolved with correct medication prescriptions and/or dietary guidelines? If not, is the level definable in percentages of patients and/or symptom resolution?

  49. Ann June 7, 2015 at 5:20 pm #

    I am on 75 mcg of synthroid. Last tsh was 1.7, ft3 was 175 and free t4 was 1.0. I have no energy and am fatter then ever. Am 55 years old. Starting to think it might be adrenal. Tried armour and it gave me bad edema so i went back to synthroid. Any comments?

  50. Tania June 24, 2015 at 12:39 am #

    Thyroid Antibodies – Thyroid peroxidase, thyroid-stimulating immunoglobulin and antithyroglobulin elevations indicate autoimmune thyroid disease such as Hashimoto’s or Graves’ disease. Thyroglobulin and calcitonin are mainly used in the diagnosis of more serious thyroid diseases such as cancer.

    So does this mean if your have high anti-tg levels your could have thyroid cancer?
    Or does it just mean you have Hashi’s?

  51. ashley July 5, 2015 at 9:33 am #

    I am 29. I have high testosterone and low ferritin and low iron. Is there a correlation? Is this indicative of a thyroid disease?

    All my other thyroid indicators come back normal. Metformin, Spirolactin, nor Iron supplements have not altered my levels at all.

  52. Ela July 17, 2015 at 6:31 am #

    Am on levothyroxine medication since February 2013. My medication fluctuate between 0.050 to 0.075 mcg. My question is currently my dr find thyroid normal in blood test but he suggest it is coming normal because am on medication. So for how long I have to stop medicines to see my real thyroid levels because am moving from USA and in India they don’t give levothyroxine and for right blood test do I have to stop medicines?

  53. Terri August 6, 2015 at 9:29 am #


    I have a low RT3 result but cannot find any implications for this. I have primary hypothyroid, taking nutritional support but no meds.


  54. Laura August 28, 2015 at 8:19 pm #

    I am struggling along trying to breastfeed and have heard that a low thyroid will effect milk supply. Do you have any information for me? I have done everything my Dr and LC have told me. I am at a loss. No one seems to have the answers. I will be forever grateful if you can help. Thank you in advance!

  55. Mary September 7, 2015 at 6:46 pm #

    Dr. Berg

    My Tsh is normal. My T3 is elevated. My T4 is low, only slightly.
    How do I improve my thyroid function? Thank you for all this info!

  56. mirriambingaman October 12, 2015 at 12:39 am #

    why ask youany thing when you can’t answer

  57. Jana November 14, 2015 at 11:30 am #

    Why is it that we are recommended to not solely rely on TSH results however most traditional Endocrinologist strictly rely on that only? Extremely frustrating when you’re feeling better and your T3 and T4 are good but your TSH shows too much hormone in your blood. I had to practically pull teeth to get my new Endo to continue with Armour. He stated he could give me Steroids that make me feel good but that doesn’t mean my body needs it when discussing up dosing for optimal results on thyroid function. :(

  58. Dr. Nikolas Hedberg November 15, 2015 at 6:25 pm #

    Endocrinologists follow a very stringent standard of care that is based on a tremendous amount of training and scientific information. Sometimes it just takes longer for things to change once new evidence is found for health conditions in conventional medicine.

  59. Dr. Nikolas Hedberg November 15, 2015 at 6:28 pm #

    This blog is for educational purposes only. Any questions regarding your individual health concerns should be discussed with your doctor. It is unreasonable and unrealistic to think that doctor’s will give medical advice on a blog. I think if you put some more time into contemplating why doctor’s can’t give advice you’ll begin to understand.

  60. LIZZ November 30, 2015 at 3:16 pm #

    Thank you for explaining the difference between TSH, Free T4, etc. I have hypothyroidism and have been struggling for years to have clear understanding of what the different tests mean. Now I can advocate for myself with my doctor. I have been searching for clear answers and now I have them.
    Thank you!

  61. Dr. Nikolas Hedberg November 30, 2015 at 3:20 pm #

    Thank you for your positive comment about the article. I’m glad it will be useful to you!

  62. Tammie December 7, 2015 at 5:41 pm #

    How do i get my T4 to brak down into T3

  63. Martha December 9, 2015 at 10:30 pm #

    I found a lot of very useful information in this article. Thank you. I have been hypothyroid since I had my first thyroid surgery, where they removed my left lobe in 2012. I had a total thyroidectomy in 09/14, and have struggled with hypothyroid symptoms to an even greater extent. I have researched and tried to learn as much as I could about this gland that I am missing, it’s role in the body and how to help myself get better. After changing doctors 4 times, I finally found the right doctor, was put on Armour, and am just about on the optimal dose. It’s like rising from the dead!! I am finally participating in my own life again, and if feels awesome! Finding articles like this one, with good information, not just that old school line about replacing the thyroid hormone with synthetic t4 in one little pill every day, and you’ll be good as new, is just great to read. I hope all these people who are suffering with thyroid problems, and do not have a competent doctor treating them, will keep seeking information, keep trying to learn more, and expect more from their health care providers. If they are not getting the help they need, move on, find someone else. Good luck and God bless!!

  64. Prasant December 21, 2015 at 7:13 pm #

    I have Graves Disease and I have been taking Synthyroid since I had the radiiactove Iodine treatment years ago. I went into Atrial Fib just prior to have the Iodine treatment. This was shown to be caused by the Hyperthroidism. My thyroid doctor kept my levels regulated for years. In the past year I have moved to another state and have a new doctor (not a thyroid specialist) monitoring my levels. Everything is in range except for the TSH which continues to get lower (going from 0.28 to 0.190). Doctor is not concerned, but I am since I just spent 2 days in the hospital with an episode of heart palpitations or possibly Atrial Fib. It reverted by quickly after 2 hours and no new episodes. Do I need to be concerned and should my meds be regulated is some way to help the TSH levels returned to normal range? Thank you for your response.


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