What Affects Male Testosterone Levels?

Male testosterone levels
The Endocrine System and Hormones

How and What Affect Male Testosterone Levels?

Most of us know that it is the testosterone in men that grants a man his male characteristics. It is the hormone that makes men virile. Some of us also realise that with age, these hormone levels decrease, and sadly a man’s virility goes with it.

  1. DHEA

Dehydroepiandrosterone is an endogenous hormone produced from cholesterol by the adrenal glands. DHEA is a precursor to oestrogen and androgen (the male and female sex hormones).


Aromatase is an enzyme that enables the body to convert testosterone into oestrogen by being a catalyst for this conversion. Oestrogen producing cells contain aromatase and are found in the adrenal glands, the testicles, the ovaries, adipose (fatty) tissue and the brain.


Even men under the age of 40 can have significantly reduced testosterone if they are obese. Increased belly fat suppresses the action of luteinizing hormone (LH) in the testes. This suppression can dramatically decrease circulating testosterone levels (Mah and Wittert 2010). There is evidence that increased aromatase levels are a direct result of excess belly fat (Kalyani and Dobs 2007).

  1. SHBG.

These initials stand for ‘Sex Hormone-Binding Globulin’. The production of SHBG is mainly in the liver. However, the brain, uterus, testes and placenta can also create it. When the SHGB is produced in the testes, it is called an androgen-binding protein. The testosterone that circulates in the bloodstream is bound to SHGB (60%) or albumin (38%). Only about 2% of testosterone is unbound, or “free”. (Morales et al. 2010). SHGB levels influence the bioavailability of testosterone because testosterone binds more tightly to SHGB than it does albumin-bound testosterone. (Morales et al. 2010).


The levels of aromatase and SHBG rise when men age. This result is the levels of oestrogen rise and the testosterone declines. When this occurs, the levels of free testosterone decreases dramatically. When levels of free testosterone drop the result is sarcopenia (loss of muscle mass), (Lapauw et al. 2008). Sarcopenia is degenerative and therefore illustrates the importance of testosterone levels in men to be at their optimum.


Keeping the liver functioning at its optimal level is also of great importance as the liver removes excess oestrogen and SHGB from the body. When there is a decrease in liver function, this causes a hormonal imbalance, which is detrimental to one’s health. To prevent further degradation that occurs with andropause, men should have regular check-ups with their GP to make sure that their liver function is optimal.


  • de Ronde, W., & de Jong, F. H. (2011). Aromatase inhibitors in men: effects and therapeutic options. Reproductive biology and endocrinology : RB&E, 9, 93. doi:10.1186/1477-7827-9-93
  • Saad, F., Aversa, A., M. Isidori, A., & J. Gooren, L. (2012). Testosterone as Potential Effective Therapy in Treatment of Obesity in Men with Testosterone Deficiency: A Review. Current Diabetes Reviews, 8(2), 131-143. doi:10.2174/157339912799424573
  • Naifar, M., Rekik, N., Messedi, M., Chaabouni, K., Lahiani, A., & Turki, M. et al. (2014). Male hypogonadism and metabolic syndrome. Andrologia, 47(5), 579-586. doi:10.1111/and.12305
  • Araujo, A. B., & Wittert, G. A. (2011). Endocrinology of the aging male. Best practice & research. Clinical endocrinology & metabolism, 25(2), 303-19.
  • Stanworth, R. D., & Jones, T. H. (2008). Testosterone for the aging male; current evidence and recommended practice. Clinical interventions in aging, 3(1), 25-44.
  • Orwoll, E., Lapidus, J., Wang, P., Vandenput, L., Hoffman, A., & Fink, H. et al. (2016). The Limited Clinical Utility of Testosterone, Estradiol, and Sex Hormone Binding Globulin Measurements in the Prediction of Fracture Risk and Bone Loss in Older Men. Journal Of Bone And Mineral Research, 32(3), 633-640. doi:10.1002/jbmr.3021
  • Collier, C., Morales, A., Clark, A., Lam, M., Wynne-Edwards, K., & Black, A. (2010). The Significance of Biological Variation in the Diagnosis of Testosterone Deficiency, and Consideration of the Relevance of Total, Free and Bioavailable Testosterone Determinations. The Journal Of Urology, 183(6), 2294-2299. doi:10.1016/j.juro.2010.02.011
  • AS, K. (2018). Androgen deficiency, diabetes, and the metabolic syndrome in men. – PubMed – NCBI . Ncbi.nlm.nih.gov. Retrieved 9 November 2018, from https://www.ncbi.nlm.nih.gov/pubmed/17940444
  • GA, M. (2018). Obesity and testicular function. – PubMed – NCBI . Ncbi.nlm.nih.gov. Retrieved 9 November 2018, from https://www.ncbi.nlm.nih.gov/pubmed/19540307
You might also like

Growth Hormone Deficiency

The Endocrine System and Hormones About Growth Hormone 191-amino acid, single-chain polypeptide Secreted by somatotropic cells located in the lateral wings of the anterior pituitary gland. Increases glucose and free fatty acid levels. Stimulates production of IGF-1...

read more