Investigating the Hormone-Thyroid Connection

What’s the connection between your hormones and your thyroid?  Learn more about the Hormone-Thyroid connection.


Testosterone is made in the testes and adrenal glands in a male, and in a woman, the ovaries and adrenal glands.  Testosterone is very important for metabolism.  It has been shown that low thyroid states result in low testosterone levels.  When the thyroid gland returns to optimal function in individuals with challenged thyroids, their testosterone levels also return to normal.  Testosterone replacement can help many conditions including thyroid and autoimmune diseases but simply giving these patients testosterone without correcting the reason why their testosterone is low in the first place does a great disservice to these patients in the long run.

Hormone Thyroid Connection

Testosterone replacement suppresses the pituitary hormone that signals the testes to make testosterone.  Once the patient comes off of the testosterone, one’s natural production may be suppressed resulting in dependence on the prescribing physician for continued hormone replacement.  There are a variety of factors that must be addressed before prescribing testosterone which should be done as a last resort.  It is very “sexy” in this day and age to get bioidentical hormones which are of course superior to synthetic hormones but still do not address underlying imbalances.

The following must be addressed before commencing testosterone replacement:

  • Liver detoxification
  • Estrogen metabolism
  • GI microflora activity
  • Insulin sensitivity
  • Adrenal function
  • Testosterone synthesis
  • 5-alpha reductase activity(converts testosterone into dihydrotestosterone)
  • Beta-glucuronidase activity
  • 17,20 lyase activity–progesterone to androstenedione
  • Aromatase activity
  • Hypothalamic-Pituitary feedback loops


Progesterone is mainly produced during the second half of a woman’s menstrual cycle.  It is manufactured mainly in the ovaries and some in the adrenal glands in women.  In men, it is made in the adrenals and testes.  Progesterone enhances thyroid hormone function but a low thyroid can result in inadequate progesterone production.

Progesterone creams bypass the intestinal tract and liver which may be more desirable than pills or sublingual drops.  Many women use progesterone cream based on symptoms which many times does more harm than good.  You should always have your hormone levels tested first before using hormone replacment.  Synthetic progesterone known as Provera, Depo-Provera, etc. has been shown to increase the risk of breast cancer by 800%.  Synthetic progesterone is not actually the progesterone that your body makes but a chemically-modified form of progesterone.

Oral progesterone seems to work the best for sleep problems that some women have because it acts on GABA receptors which calms the brain and nervous system.


Estrogen is made in the ovaries in cycling women but the majority of estrogen in a menopausal woman is made in the adrenal gland.

There are three types of estrogen:

  • Estrone or E1–10%
  • Estradiol or E2–10%
  • Estriol or E3–80%

The percentages indicate the amount that is naturally produced in the body.  Synthetic estrogens are given in very high doses of estrone or estradiol with little to no amount of estriol throwing off the natural balance of estrogen in a woman’s body.  This is one of the reasons why the Women’s Health Initiative was stopped before its completion due to the many side effects.

Estrogen is important for healthy bones, brain function, sex drive and function and may have a protective effect from heart disease.  As with any hormone, too much estrogen can have negative effects, especially an increased risk of breast cancer.  We are living in an estrogen-dominant world due to the many chemicals that act like estrogen known as xenoestrogens.

Elevated estrogen can be due to stress, diet, exposure to xenoestrogens and impaired hormone detoxification systems.  Stress will actually free inactive estrogen to active estrogen leading to side effects such as water retention, breast cysts, moodiness, and weight gain.  Conventional meat from animals injected with estrogen can be a problem as well.  The excess estrogen in the animals leads to weight gain from water retention increasing profits due to more money per pound.  Fiber, liver detoxification, stress reduction and the elimination of conventional dairy and meat in the diet will lower excess estrogen.

We know that excess estrogen can lead to low thyroid function.  The mechanism behind this is simply an inhibition of the conversion of inactive T4 into active T3 as well as estrogen binding to the proteins to which thyroid hormone would normally bind.

Women who are taking synthetic estrogens such as Premarin, Prempro and the birth control pill will most likely have low thyroid function due to the excess estrogen.  Many times, cleansing the body of excess estrogen and ensuring proper estrogen metabolism in the liver can clear the symptoms of hypothyroidism.


Pregnenolone or “the mother of all hormones” is made from cholesterol mainly in the adrenal glands.  As its name suggests, it is the precursor to all of your sex hormones including testosterone, estrogen, progesterone, DHEA and cortisol.  Pregnenolone is found in its highest concentration in the brain and is important for memory and brain function.  Research has shown that those with low thyroid function also have low pregnenolone levels.  We use time-released pregnenolone in our patients for a slower release over time.  Remember that too much cortisol inhibits thyroid function but on the flip side you need some cortisol to convert inactive T4 into active T3.  Patients tend to notice an instant increase in energy and memory and have an improved sense of well-being once they begin taking pregnenolone.


DHEA is a steroid hormone produced in the adrenal gland.  There is plenty of research showing that patients with low DHEA levels also have low thyroid function.  DHEA is not taken for long periods of time, however, as it can cause hormonal imbalances if not taken correctly.  DHEA has its own effects in the body including proper immune function, fat burning, muscle building, tissue repair, proper liver function and energy production.  DHEA will also convert into other sex hormones such as estrogen and testosterone.  When DHEA is given to a woman, it will most likely convert into testosterone but in a man it will most likely convert into estrogen.  DHEA received a lot of press as an anti-aging hormone which led to abuse of its over-the-counter availability.  DHEA should not be taken without proper testing first and it should be taken in the lowest dose possible.


Cortisol is made in the adrenal gland to raise blood sugar into the normal range but chronic elevations of cortisol can lead to blood sugar problems.  Cortisol in high doses is a catabolic hormone meaning it breaks down the body’s tissues.  Cortisol also eats away at the area of the brain that is involved in memory known as the hippocampus.  Cortisol is also required for an adequate immune response to infection so if you have trouble recovering from infections you may have inadequate adrenal gland function.  Cortisol converts into cortisone which is your body’s natural anti-inflammatory.  Too much cortisol will suppress TSH (thyroid-stimulating hormone), inhibit the conversion of inactive T4 into active T3 and also directly block thyroid hormone receptors.  Cortisol is required, however, to convert inactive T4 into active T3 making it very important for proper thyroid hormone function.

The adrenal glands may need to be treated before the thyroid is treated due to the fact that too much thyroid hormone can make already imbalanced adrenals even worse.  I have also found that once the adrenals are functioning optimally, many patients’ thyroid symptoms resolve indicating it was not a thyroid problem in the first place.

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