Thyroid School, Issue 2// Thyroid Hormone Production

If you missed Thyroid School: Issue 1, you can find that here!

Let’s chat about where thyroid hormone production truly begins…


When levels of circulating thyroid hormone are too low in the body, the hypothalamus secretes Thyrotropin Releasing Hormones (TRH) which then tells  the pituitary gland (a portion of the brain that acts like a thermostat), to secrete Thyroid Stimulating Hormone (TSH), which tells the thyroid to secrete more thyroid hormone.  It is a built in feedback signal to prevent the body from getting deprived of thyroid hormones.

Hypothyroidism occurs when levels of free thyroid hormone (mainly T4 and T3) are too low. This triggers the feedback loop to the brain to produce TRH and TSH. When levels of TSH rise, the thyroid puts out more and more thyroid hormone. This explains why a HIGH TSH is a diagnostic criterion for hypothyroidism.

Technically speaking, TSH is a brain hormone and not a thyroid hormone!

Symptoms of Low Thyroid include:

  • Fatigue
  • Sluggishness
  • Difficulty concentrating
  • Feeling cold all the time
  • Coarse, dry hair
  • Thinning hair
  • menstrual irregularities (lack of period, irregular periods, or abnormally heavy periods)
  • Subfertility
  • Decreased libido
  • Fluid Retention
  • Constipation
  • Weight Gain
  • Fibrocystic breasts
  • Polycystic Ovary Syndrome
  • Premenstrual Syndrome (PMS)
  • Feeling of rapid heart-beat or skipped beats
  • Elevated homocysteine
  • Galactorrhea (being able to express milk without being pregnancy or actually lactating)

The root cause(s) of hypothyroidism can first be split into two major groups:

1. Autoimmune

– Hashimoto’s

2. Not autoimmune

– Inadequate production of thyroid hormone (not enough thyroid hormone coming out)

– Cellular resistance to thyroid hormone (thyroid hormone being produced, but either not converting to “active” form and or not being used by cells the right way)

It is important to determine the root cause of your hypothyroidism so that you can best manage it. While the medication intervention may be consistent regardless of the etiology, the nutritional and lifestyle management do differ depending on the root cause. For example, let’s say your root cause of hypothyroidism is autoimmunity. If there isn’t a plan in place to manage your autoimmune disease, then the destruction of your thyroid will continue. Medications help to replace the lost thyroid hormone, but don’t stop the disease progression. (No worries, I’ll talk a LOT more about this soon!)

Additionally, let’s say that you have cellular resistance to thyroid hormone. Taking more medication may not help as much as you would hope for. The goal of nutritional therapy is to get your body to a place where it is more responsive to your medications and allows for the most optimal functioning of your thyroid (which varies from person to person depending on their disease progression!).

Next post, I’ll be reviewing the different contributors to hypothyroidism.

Here are ways I can help!

Disclaimer: Please note that “Thyroid School” emails from Chews Food Wisely, LLC (and Nicole Fennell, RD) are not intended to create any physician-patient relationship or supplant any in-person medical consultation or examination. Always seek the advice of a trained health professional with any questions you may have regarding a medical condition and before seeking any treatment. Proper medical attention should always be sought for specific ailments. Never disregard professional medical advice or delay in seeking medical treatment due to information obtained in “Thyroid School” emails. Any information received from these emails is not intended to diagnose, treat, or cure. These emails, websites, and social media accounts are for information purposes only. The information in these emails, websites, and social media accounts are not intended to replace proper medical care.