Written by Leann Poston, M.D.
Thyroid disease in men can cause low sperm count, loss of muscle mass, and erectile dysfunction. Thyroid disease is much more common in women, so men may not attribute symptoms unique to men as secondary to thyroid disease. However, men tend to have increased thyroid problems with age.
The endocrine system is complex. A slight change in one hormone can have far-reaching consequences throughout the body. Testosterone levels decline at a rate of about one percent per year, beginning around the age of 30.
Because of the interrelationship between hormone functions, you may notice symptoms that seem unrelated. It can be difficult to diagnose low testosterone levels. Once your testosterone levels are low enough to cause symptoms, such as
The diagnosis may be clear.
However, most men want to take whatever steps possible to prevent these symptoms from developing. You can support your body’s ability to make testosterone by getting enough sleep, eating nutrient-dense foods with healthy sources of protein and fats, and engaging in physical activity that improves strength, balance, and cardiovascular fitness.
If these lifestyle changes are not enough to reverse or at least improve your symptoms, consider having your testosterone levels tested.
It is also important to determine whether an abnormal thyroid hormone level is causing your symptoms. Sexual dysfunction affects 59-63 percent of men with hypothyroidism and 48-77 percent of men with hyperthyroidism (Gabrielson et al., 2019).
The thyroid gland is a butterfly-shaped gland on the front of the neck. It releases two hormones, triiodothyronine (T3) and thyroxine (T4). These hormones regulate:
Thyroid function also affects growth hormone production, cortisol (stress hormone) levels, glucocorticoid levels, and gonadal function (Merkle, 2004). It is very difficult to isolate the functions of one hormone from the rest.
The thyroid gland is regulated by a negative feedback loop. When T4 levels are too low, the hypothalamus produces thyrotropin-releasing hormones (TRH), and the pituitary gland produces thyroid-stimulating hormone (TSH) to prod the thyroid to increase production. Conversely, if T4 is too high, TRH and TSH production is inhibited.
A properly functioning thyroid gland produces just the right amount of thyroid hormone to meet the body’s needs. If too much thyroid hormone is produced, it is called hyperthyroidism. If too little is produced, it is called hypothyroidism.
Hypothyroidism is a condition in which the thyroid gland does not produce enough thyroid hormone. Thyroid hormone production can be adequate for normal body function, inadequate or subclinical, which means that TSH levels are slightly above the upper range of normal but not enough to warrant a diagnosis of hypothyroidism.
The hypothalamus secretes gonadotropin-releasing hormone (GnRH). GnRH stimulates the anterior pituitary gland to produce luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH stimulates testosterone production in the testes.
Testosterone is transported through the bloodstream, primarily bound to the protein sex hormone-binding globulin (SHBG), though some can be carried by another protein called albumin. A small amount of testosterone, free testosterone, is not bound to a protein.
Increased TSH levels due to hypothyroidism cause a decreased LH response to GnRH. Recall that LH stimulates the testes to produce testosterone. This abnormal response is associated with low testosterone levels. Men with hypothyroidism have low free testosterone levels. However, when thyroid hormone levels are normalized, testosterone levels return to normal as well (Meikle, 2004; Kumar et al., 1990).
Hypothyroidism can also cause an increase in prolactin levels, a hormone that stimulates milk production in nursing mothers. Increased prolactin levels can also lower testosterone levels (Chen et al., 2018).
Subclinical hypothyroidism has been linked to lower testosterone levels and higher prolactin levels. However, more research is needed to determine the significance of this finding (Kumar et al., 2006).
Hyperthyroidism is a condition in which the thyroid gland produces too much thyroid hormone. Grave’s disease, an autoimmune disorder, is often the cause of hyperthyroidism. The connection between hyperthyroidism and testosterone is less clear, but there is evidence that changes in thyroid hormone levels can affect how testosterone is delivered in the bloodstream.
Men with hyperthyroidism have higher testosterone levels, higher sex hormone-binding globulin (SHBG) levels, and an increased LH response to GnRH (Meikle, 2004).
High SHBG levels are associated with a drop in free testosterone levels. Men with hyperthyroidism may have changes in how the hypothalamus, pituitary, and testes interact, which may also cause symptoms (Hudson & Edwards, 1992).
The first step is to have a thorough history and physical exam. After that, your healthcare provider may advise you to have your TSH and T4 levels taken to screen for thyroid disease. If your thyroid function is abnormal, the next step is to determine the cause and discuss treatment options.
Once your thyroid hormone levels have been corrected, your doctor may test your testosterone levels.
The American Urological Society defines low testosterone (Low-T) as less than 300 nanograms per deciliter (ng/dl). Low testosterone levels can cause a low sex drive, decreased lean muscle, irritability, fatigue, erectile dysfunction, and depression.
Total testosterone levels measure testosterone that is mostly bound to SHBG and albumin, whereas free testosterone measures unbound testosterone.
Side effects can occur when testosterone is used incorrectly or at an excessively high level. Therefore, it is important to work with your healthcare provider to ensure that you can maximize the benefits of testosterone replacement therapy while minimizing the risks.
The best online programs and treatment facilities offer an evaluation for low testosterone, followed by a requirement for a prescription for testosterone replacement therapy by a licensed health care provider. Invigor Medical is a full-service telemedicine healthcare provider that partners with a fully licensed, U.S.-based pharmacy to provide online healthcare.
Learn More: “How Long Does Testosterone Replacement Therapy Typically Last?”).]
While we strive to always provide accurate, current, and safe advice in all of our articles and guides, it’s important to stress that they are no substitute for medical advice from a doctor or healthcare provider. You should always consult a practicing professional who can diagnose your specific case. The content we’ve included in this guide is merely meant to be informational and does not constitute medical advice.
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2. Gabrielson, A. T., Sartor, R. A., & Hellstrom, W. J. G. (2019). The impact of Thyroid Disease on Sexual Dysfunction in men and women. Sexual Medicine Reviews, 7(1), 57–70.
3. Chen, D., Yan, Y., Huang, H., Dong, Q., & Tian, H. (2018). The association between subclinical hypothyroidism and erectile dysfunction. Pakistan journal of medical sciences, 34(3), 621–625. https://doi.org/10.12669/pjms.343.14330
4. Kumar, A., Chaturvedi, P. K., & Mohanty, B. P. (2007). Hypoandrogenaemia is associated with subclinical hypothyroidism in men. International Journal of Andrology, 30(1), 14–20. DOI: 10.1111/j.1365-2605.2006.00705.x
5. Jaya Kumar, B., Khurana, M. L., Ammini, A. C., Karmarkar, M. G., & Ahuja, M. M. (1990). Reproductive endocrine functions in men with primary hypothyroidism: effect of thyroxine replacement. Hormone research, 34(5-6), 215–218. https://doi.org/10.1159/000181828
6. Hudson, R. W., & Edwards, A. L. (1992). Testicular function in hyperthyroidism. Journal of andrology, 13(2), 117–124.
7. Melish, JS Thyroid Disease. In: Walker HK, Hall WD, Hurst JW, editors. (1990). Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; Chapter 135. https://www.ncbi.nlm.nih.gov/books/NBK241/