Thyroid 101 Guide – Key Hormones for Regulating Your Metabolism


The thyroid gland is a butterfly shaped endocrine gland which wraps around your windpipe at the base of your neck, below your Adam’s apple. The thyroid gland uses iodine to produce thyroid hormones. Iodine from the blood combines with amino acids to form thyroid hormones. Now that you know where to find your thyroid gland, you are probably wondering what exactly is a thyroid and endocrine gland? The endocrine gland secretes hormones to keep your body regulated. This gland sends out “hormone messengers” which control tissue growth, metabolism, mood and body temperature.

The Thyroid Captain: What Does The Thyroid Control?

Think of your body as a vessel and the thyroid is your personal captain, controlling different body functions. Your “thyroid captain” is quite the multitasker, regulating your breathing, heart rate and even body temperature. Did you know that thyroid hormones also regulate other body functions such as your central and nervous systems, cholesterol levels, muscular strength, body weight, and for women, menstrual cycles?

The Captain’s Boss: What Controls The Thyroid Gland?

So every boss has a boss and in this case, the thyroid gland’s boss is the pituitary gland. So what exactly is the pituitary gland’s job? If the pituitary gland were to actually speak when a problem is noticed in your body it would say, “Hey, body, I notice that there isn’t enough thyroid hormone in your blood, I’m going to release TSH (thyroid stimulating hormone).” This creates more thyroid hormone production basically “waking up” your thyroid. The pituitary gland can also notice when you have too much thyroid hormones in your blood and decrease the TSH levels, decreasing the production of thyroid hormones.

Healthy Thyroid: How Do You Know if Your Thyroid is Healthy?

So how do you know if your thyroid is healthy? Before going to the doctor and getting blood work (which is really, the most accurate way to know) you can do a simple self check with the following two scenarios. As you read each scenario, think about your current symptoms to see if either one describes your current state.

Scenario #1: Underactive Thyroid

You wake up one morning, after sleeping 8-10 hours, which is an optimal amount of rest, but you still feel tired and during the day you may either take a nap or feel the need to have one. During the day, you feel anxious, moody or just plain down in the dumps. To make matters worse, your muscles ache and you may even have joint pain, tendinitis or carpal tunnel syndrome. Despite your pains, you go to the gym, eat healthy and try to lose weight, but nothing seems to help you shed those unwanted pounds. You may notice that your skin is dry or cracked, your nails are brittle and your hair just isn’t as thick as it used to be. While hanging out with your friends you notice your hands and feet are cold and you ask, “Is it cold in here?” and then your dismay, your friends respond by telling you it isn’t cold and that it must be just you who is feeling cold. You decide to check your body temperature and notice that it is below 98.5 degrees, which is low. Your day just keeps getting worse when you experience batches of brain fog, poor concentration and poor memory. Even going to the bathroom is a challenge, but wait, you find that you can’t go to the bathroom and constipation is your next problem. As you end the night with what you think is a good night’s sleep, you rub your neck and notice that it feels swollen and in a hoarse voice, ask your significant other if you were snoring last night and the look on their face confirms it. If this scenario describes your current health situation, you may have an underactive thyroid (hypothyroidism).

Scenario #2: Overactive Thyroid

You just can’t seem to get a good sleep which leaves you feeling tired and weak. Even if you do get sleep, the weak, tired feeling lingers with you throughout the day. During the day, you feel on edge, anxious, nervous and irritable. Your mood goes from one feeling to the next and you can’t explain it. Frequent trips to the bathroom to release your bowels is another problem. As you pull up your pants, you notice they feel a little looser and decide to take a step on the scale. You notice that your weight has dropped considerably and you really have no rational explanation for the sudden weight loss. Speaking of loss, you notice that your hair is thinner and even brittle. As you continue throughout the your day you notice your hands and even fingers are shaking, almost like tremors. Your heartbeat also feels off with irregular heartbeats, palpitations or even pounding. You notice that the base of your neck looks swollen (this can be caused by an enlarged thyroid which is called a goiter). You are also very sensitive to heat. If this scenario describes your current health condition, you may have an overactive thyroid (hyperthyroidism).

Blood Tests for Thyroid: What is Tested and What are Optimal Levels?

You’ve decided to go to your doctor, and after describing your symptoms, your doctor may suggest blood tests for your thyroid. It is important that you know the fundamental components of a full blood lab for your thyroid in order to have a complete picture of your thyroid condition. A complete thyroid panel consists of the following tests:

  • TSH
  • Free and Total T4
  • Free T3
  • Reverse T3
  • TPO (Thyroid Peroxidase Antibodies)
  • TSI (Thyroid Stimulating Immunoglobulin)

Now you are really feeling anxious and wonder what in the world are these tests and how will you know what is normal and abnormal when you receive the results. Of course your doctor will report the levels to you but it is always helpful to have a general understanding of the tests for yourself.

TSH (Thyroid Stimulating Hormone) is a test which measures how much of this hormone is in your blood. It is best to have this test in the morning since your TSH levels increase and decrease throughout the day. A normal range of TSH is 0.4-5.5 mU/mL (milliunits per millimeter). So what is mU/mL? Since TSH is measured in fluid volume, that is equal to one-thousandth of a liter (a little less than ¼ of a tsp.). Another way to measure TSH is Ulu/mL and the range is 0.27-4.20. Some labs will go as high as 5.00 mIU/L, however, the normal range is 0.4-4.0. If your levels are between 3.5-4.5 but you have symptoms of hyperthyroidism, then you may want to take medication to find the optimal range. The “optimal range” can vary from person to person. Documenting your symptoms daily in a log and sharing this information with your doctor can be very helpful.

TSH Levels: How To Increase or Decrease for Optimal Health?

TSH levels can be decreased by taking aspirin, corticosteroids or heparin therapy. There are also certain vitamins and minerals which can help increase TSH levels such as zinc, omega-3 fats and selenium. Diet is another way that TSH levels can be improved. Iodine rich foods are extremely important since iodine is the basic building block of the thyroid. There are 7 main iodine rich foods:

  1. Sea Veggies (kelp, hiziki, arame)
  2. Cranberries
  3. Yogurt
  4. Navy Beans
  5. Strawberries
  6. Cheese (goat and cheddar)
  7. Potatoes (with the skin left on)

Other foods can help increase your levels such as tuna, mushrooms, beef and halibut which have a high concentration of selenium. Lamb, pecans and almonds are all great resources for zinc. There are also some foods to avoid since the consumption of these foods disrupts the thyroid. Soy, such as soybeans is on the list, however, natural soy is not a problem. Veggies in the Brassica food family such as Brussels sprouts, cauliflower, broccoli and cabbage are also added to this list.

Certain exercises can also help improve thyroid hormone levels. Moderate-intensity exercise increases the amount of thyroid hormone circulating in the body. It is recommended to perform 30 minute moderate workout sessions 4-5 times per week. Just 3 minutes of moderate bicycling or even a moderate jog can boost the thyroid gland. Rowing, swimming, walking, and strength training exercises like lunges, push-ups and interval aerobics are also a few exercise options which will enhance thyroid performance. Not all forms of exercise help the thyroid however. Yoga is one type of exercise which does not boost thyroid function. Heat therapy such as saunas can help get rid of stored toxins which inhibit optimal thyroid function.

T4: Thyroxine and Free T4

Free T4 hasn’t bonded to protein in your blood and is available for use by your body and tissues. Most T4 is bonded to protein. The Total T4 test reports what is available for your body tissues to use (extra). The normal range for total T4 is 4.5-12.5 and the normal range for Free T4 is .93-1.70 ng/dL. Total or free T4 levels that are below the reference range fall into the hyperthyroidism category. Total T4 and Free T4 levels that are above the reference range are also in the hyperthyroidism category.

Free T3

Most T3 is bound to a protein and can be affected by high protein levels and even protein binding ability, but T3 is not affected. This hormone has the most biological power. It is also used to diagnose Graves disease (an autoimmune disorder and the most common cause of hyperthyroidism). This test is usually ordered when you have an abnormal TSH result. The range for adults who are 19 years or older is 2.0-4.4. Levels in the top half of the reference range are considered evidence of a healthy thyroid (over 3.0), and levels in the top 25% are considered optimal.

Reverse T3

T4 can be converted into T3 or Reverse T3 depending on the removal of an iodine atom. A healthy thyroid transforms 40% of T4 to T3, and 20% is changed to Reverse T3, daily. Added stress in a person’s life and the need for the body to conserve energy my cause the percentages to change which affects hormone availability. Reverse T3 keeps hormones in balance, but high levels can result in hyperthyroidism. The range of Reverse T3 is 8-24 (ng/dL). The lower half of the normal range is considered optimal.

The TSH and T3/T4 Diagnosis: What is a Healthy Combination?

ConditionTSH LevelFree T4Free or Total T3
Mild HypothyroidismHigh or LowNormalNormal
HypothyroidismHighLowLow or Normal
Thyroid Hormone Resistance Syndrome (mutation that decreases thyroid hormone function)NormalHighHigh

Reading Thyroid Blood Labs: How To Interpret Blood Lab Results?

In the images below, you will see two lab reports. The first lab report was what you call the “baseline” or B.T.H.T. (Before Thyroid Hormone Therapy). As you can see, in March of 2017, the individual (female) had results which fell within the reference interval. The TSH was 1.64, which is on the lower end of the interval. This is where the “Thyroid Community” gets very controversial. The hunt for the “one and only” optimal TSH level is like hunting for a needle in a haystack. You probably aren’t going to find that one special needle, instead, you will find many different research studies and opinions. It is very difficult to decipher fact from fiction in the TSH world. The best advice is to document how you feel by keeping a daily journal. Your optimal TSH level may not be the same as the next person. The T4 level was normal, however, the T3 free hormone was not in the optimal range. The Reverse T3 level was not in the lower half range and therefore was not in the optimal range. This person (female) started hormone pellet therapy and was prescribed 5mcg of Liothyronine per day. This drug is used to treat an underactive thyroid, otherwise known as hypothyroidism. Liothyronine, provides extra thyroid hormone which is usually the thyroid gland’s job. It is a man-made hormone and also used to treat thyroid cancer and certain types of goiters. The person (female) continued this treatment for 7 months and went from a TSH of 1.64 to a TSH of 4.99 which is high. Since the thyroid has so many parts, it is important to understand how different treatments can all affect each person differently. Attempting to get thyroid hormone levels to their optimal condition can be very challenging and even risky.


Thyroid Therapy Medications: What are The Options?

Thyroid hormone replacement therapy can be used to support the thyroid gland, however, it is not a “one size fits all” approach. One consistency with all thyroid medications is the optimal time to take it, which is first thing in the morning on an empty stomach. There are natural made hormones and man-made ones. Westhroid is a naturally prepared hormone, produced by porcine thyroid glands. This grain replaces both T3 and T4 hormones. Synthetic T4 hormone medication is prescribed as Synthroid or Levoxyl. These drugs contain corn and lactose ingredients. These thyroid replacement hormones provide a steady dose of T4 that your body converts to T3. Many people may have problems with these drugs when they have difficulty converting T4 into T3. It is very important to remember that if you decide to take hormone replacement therapy drugs, make sure that your doctor routinely checks your TSH, T4 and T3 levels.

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