Testosterone is one of the essential sex hormones that plays a crucial role in development and various functions of the body, with its amount being mostly important for men. It is the most significant hormone within the group of androgens. The primary source of testosterone in males are the testicles, where testosterone is both synthesized and stored. However, small amounts of testosterone are synthesized in female ovaries too. The adrenal glands produce androgens as well, although different kinds and to a smaller extent but with very similar functions. The level of testosterone can vary widely depending on age, time of a day, and many other factors.
In men, testosterone has several vital functions. Before the birth, it determines the gender of the embryo. During male puberty, it provides the growth of bones, muscles, hair, penis, testicles and causes the deepening of voice. In adults, it regulates sex drive (libido), influences bone mass, affects fat distribution, contributes to muscle mass and strength, and secures sperm production, together with other hormones such as luteinizing hormone (LH) and follicles stimulating hormone (FSH).
In women, testosterone is important for the growth of bones, muscles, and healthy organs.
The pituitary gland in the brain controls the amount of testosterone that the body makes. It does this by using other signaling hormones such as gonadotropin releasing hormone (GnRH) or luteinizing hormone (LH).
The significance of testosterone extends beyond its physiological roles. It serves as a biomarker that aids in diagnosing and monitoring various conditions affecting the male and female endocrine systems. These conditions in males include hypogonadism (insufficient testosterone production), infertility, erectile dysfunction, and prostate cancer.[1,2] In females, testosterone can be used to diagnose and monitor disorders such as ovarian cancer or polycystic ovary syndrome (PCOS). Furthermore, abnormal testosterone levels may indicate a problem not only within the gonads but also with the pituitary or adrenal glands.
By evaluating testosterone levels, healthcare professionals can gain valuable insights into the functioning and health of the male and female reproductive systems.[1,3]
Each laboratory uses different machines and protocols, so the results might vary in terms of the reference ranges or used units of measurement. In Macromo blood tests, we use nmol/l (nanomoles per liter), but you may also find values in ng/dl (nanograms per deciliter) on the internet.
Testosterone in your body exists as free testosterone (not attached to anything), and bound testosterone, which is attached to proteins such as albumin and sex hormone-binding globulin (SHBG). Total testosterone measures both of these forms. Only 1 to 2% of the circulating testosterone around your body is classified as free testosterone. An average of 80% of testosterone found in men is bound to sex hormone-binding globulin (SHBG), while smaller percentages are bound to albumin and cortisol-binding globulin.
Normal levels fall between 7 and 26 nmol/l in men and between 0.3 and 2.3 nmol/l in women. Low testosterone levels in men may cause symptoms such as decreased sex drive, erectile dysfunction, fatigue, and depression, while high levels may cause acne, mood swings, and an increased risk of heart disease.
It's important to note that testosterone levels can fluctuate throughout the day and can be influenced by factors such as diet, stress, and overall hormonal balance.
There are three possible states of your blood test result: low, average, and high levels.
While genetics can contribute to individual variations in testosterone levels, it's important to note that they interact with various environmental and lifestyle factors. Overall health status, lifestyle, external factors and aging can also influence testosterone levels significantly.
Research that has focused on testosterone's effect on human diseases stated that testosterone levels in men and women are partly heritable (~20%) and influenced by the contribution of multiple genetic variants and genes.[4]
Several genes have been identified as influential factors, including the androgen receptor gene (ARgene), which affects the sensitivity of cells to testosterone. Variations in this gene can alter the response to otherwise normal levels of testosterone, leading to the same hormonal disbalance as with the low/high testosterone levels.[5]
The sex hormone-binding globulin (SHBG), a protein that binds to testosterone and regulates its availability, is also influenced by genetic variations. Changes in the SHBG gene can impact the levels and activity of this protein, consequently affecting the amount of free and active testosterone in the body.[6]
If your test results are outside the reference range, it is advisable to consider taking some of the steps listed below:
The information and tests provided on our website are for educational purposes only and are not a substitute for professional medical advice. Always consult with your healthcare provider before making health decisions. Our tests do not diagnose or treat diseases. Individual results may vary and should be discussed with a healthcare provider.
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Continue to ShopIf your test results are outside the reference range, it is advisable to consider taking some of the steps listed below:
[1] Testosterone Test. WebMD. Accessed July 7, 2023. https://www.webmd.com/a-to-z-guides/testosterone-test
[2] Understanding How Testosterone Affects Men. National Institutes of Health (NIH). Published May 14, 2015. Accessed July 7, 2023. https://www.nih.gov/news-events/nih-research-matters/understanding-how-testosterone-affects-men
[3] Fiamegos A, Varkarakis J, Kontraros M, et al. Serum testosterone as a biomarker for second prostatic biopsy in men with negative first biopsy for prostate cancer and PSA>4ng/mL, or with PIN biopsy result. Int braz j urol. 2016;42(5):925-931. doi:10.1590/s1677-5538.ibju.2015.0167
[4] Greenhill C. Genetic analysis reveals role of testosterone levels in human disease. Nat Rev Endocrinol. 2020;16(4):195-195. doi:10.1038/s41574-020-0338-8
[5] Panizzon MS, Bree K, Hsieh TC, et al. Genetic Variation in the Androgen Receptor Modifies the Association Between Testosterone and Vitality in Middle-Aged Men. The Journal of Sexual Medicine. 2020;17(12):2351-2361. doi:10.1016/j.jsxm.2020.08.016
[6] Akkaliyev M, Aukenov N, Massabayeva M, Apsalikov B, Rakhyzhanova S, Kuderbaev M, Sadykov N. Effect of SHBG Polymorphism on the Levels of Bioavailable Testosterone and Lipid Metabolism in Older Men of the Kazakh Population. Open Access Maced J Med Sci Available from: