Free testosterone, a fraction of the total testosterone in the blood, plays a pivotal role in various physiological processes. Unlike testosterone bound to proteins like Sex Hormone-Binding Globulin (SHBG) and albumin, free testosterone is unbound and readily available for use by the body's cells.
Testosterone is a vital hormone predominantly produced by the testes in men and, to a lesser extent, the ovaries in women. A small amount is also made in the adrenal glands. While most testosterone in the bloodstream is bound to proteins, a small portion remains unbound and is referred to as free testosterone. This fraction is crucial, as it can enter cells and activate receptors, influencing many physiological processes, including reproductive function, muscle development, and mood regulation.[1]
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 pmol/l (picomoles per liter).
Free testosterone level is an accurate indicator of hormonal health, especially in conditions where SHBG levels are altered. Optimal levels of free testosterone range between 25-75 pmol/l in men and between 2-12 pmol/l in women. Optimal values depend on the age of the individual. Low free testosterone levels in men may cause symptoms such as fatigue, decreased libido, and sexual dysfunction.[2] Free testosterone levels can naturally decline with age, especially in men. Interpreting free testosterone levels should be done in conjunction with other hormone levels and clinical symptoms.
There are three possible states of your blood test result: low, average, and high levels.
Certain genetic variations can affect the production of testosterone and the levels of SHBG, which can alter the amount of free testosterone.[3,4] It's also essential to consider the interplay between genetic and environmental factors such as diet, exercise, and stress, as these can significantly impact hormonal levels.
If your free testosterone levels are not within the optimal range, it is important to determine the cause[1]. However, each person's hormonal profile is unique, and what might be considered an optimal free testosterone level for one individual may differ for another:
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 total testosterone levels are outside of the optimal range, it's important to speak with a doctor. Depending on the specific situation, they may recommend additional testing, lifestyle changes, or medical treatment. Treatment options may include hormone replacement therapy, medication, or lifestyle changes such as weight loss or exercise.
[1] Free Testosterone - Health Encyclopedia - University of Rochester Medical Center. Accessed July 8, 2023. https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=testosterone_free
[2] Testosteron v séru: https://www.nempt.cz/files/lab_prirucka/_LP_07597.htm
[3] Ohlsson C, Wallaschofski H, Lunetta KL, et al. Genetic Determinants of Serum Testosterone Concentrations in Men. Abecasis GR, ed. PLoS Genet. 2011;7(10):e1002313. doi:10.1371/journal.pgen.1002313
[4] Male Testosterone Levels Influenced By Genetic Makeup. Published October 10, 2011. Accessed July 8, 2023. https://www.medicalnewstoday.com/articles/235724
[5] Antonio L, Pauwels S, Laurent MR, et al. Free Testosterone Reflects Metabolic as well as Ovarian Disturbances in Subfertile Oligomenorrheic Women. Int J Endocrinol. 2018;2018:7956951. Published 2018 Sep 10. doi:10.1155/2018/7956951