Thyroid and testosterone production

How does your thyroid status affect your androgen levels?

The thyroid produces two hormones, namely T4 and T3. T4 is converted to T3 via the deiodinases enzyme and T4 levels are always higher than T3 levels. T4 is just considered as a pro-hormone, as it’s converted to T3, which is the active hormone. T3 binds with much greater affinity to thyroid receptors than T4. Thyroid receptors form heterodimers with vitamin A receptors (Retinoid X receptors), meaning vitamin A and thyroid hormones (TH) work in synergy.

Hypothyroidism in the adult is associated with severe intellectual defects, abnormal balance and defects in fine motor skills, plasticity, and deafness (1). Correcting TH deficiency is critical for normal brain development and function. TH increases insulin sensitivity, oxidative defense systems (superoxide dismutase (SOD), glutathione), glucose uptake in muscles, blood sugar regulation, energy expenditure, etc… However, hypothyroid is not only due to low thyroid hormones, but could also be due to low conversion of T4 to T3. However that is for another post.


Cortisol: Cortisol and aldosterone production and the clearance rate thereof is dramatically increased by hyperthyroidism and decreased by hypothyroidism. However, it has a much shorter half-life in the system, due to increased clearance, thus exerting a weaker action. Cortisol is also more rapidly converted to cortisone (it’s inactive form). (2)

DHT: Testosterone and DHT production is dramatically increased in hyperthyroidism and their clearance rate is decreased. The most dramatic increase was noted for DHT, with plasma levels increasing by 8-10 times over the average values found in euthyroid men. The data on testosterone was pretty similar to DHT. Decrease clearance and a slight increase in free testosterone. Conversion of testosterone to its weaker metabolite androstenedione is significantly decreased, but conversion of androstenedione to testosterone is increased two fold. There was an increase in SHBG (sex hormone binding globulan), but free T is still greater during hyper than euthyroid. SHBG also decreases the metabolic clearance rate of testosterone. More on SHBG here

Estrogen: There is accelerated conversion of estrone and estradiol into estriol, which is the “weakest” of the estrogens and is often used as finial form to be excreted in urine. High TSH (thyroid stimulating hormone) due to hypo also increases prolactin. The increased SHBG will help bind free estrogen and excrete it through the urine. Estrogen clearance in the body is increased during hyperthyroid.

Thyroid hormones acutely stimulate Leydig cell steroidogenesis. Thyroid hormones cause proliferation of the cytoplasmic organelle peroxisome and stimulate the production of steroidogenic acute regulatory protein (StAR) and StAR mRNA in Leydig cells; both peroxisomes and StAR are linked with the transport of cholesterol, the obligatory intermediate in steroid hormone biosynthesis, into mitochondria. (2)

Hyperthyroid also 1) increases androgen receptors, 2) increases IGF-1 and IGFBP-4, 3) decreases estrogen receptors, 4) inhibits the aromatase and 5) decreases androgen binding proteins.

T3 directly increases Leydig cell LH (luteinizing hormone) receptor numbers and mRNA levels of steroidogenic enzymes and steroidogenic acute regulatory protein. It stimulates basal and LH-induced secretion of progesterone, testosterone, and estradiol by Leydig cells. Steroidogenic factor-1 (regulates the transcription of StAR) acts as a mediator for T3-induced Leydig cell steroidogenesis. (2)

When the testes are damaged (by oxidative stress for e.g.), thyroid hormones help to repair the damage by generating new (differentiation) Leydig cells. (2)

But beware, chronic thyroid supplementation actually decreases steroidogenesis.

Best ways to boost your thyroid function.

  • TyroMax – 99.9% purity x3 strength USP desiccated thyroid glandular. 1 grain per 1/3 serving, 90 servings.
  • Liquid organic Iodine – 150mcg per serving, 480 servings
  • Kelp – 225mcg per serving, 500 servings

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