Mar282024
TestosteroneTotal Testosterone vs Free Testosterone

Free testosterone vs total testosterone: The Facts

At TRT Nation, we prioritize transparency and accuracy in our approach to patient care. One question frequently asked by our patients pertains to our lab testing protocols, particularly why we primarily test for total testosterone rather than free testosterone, and why our lab panel does not include cholesterol. In this article, we aim to address this inquiry with precision and clarity, rooted in scientific evidence and medical expertise.

Free Testosterone vs Total Testosterone

The Comprehensive Measure Total testosterone levels serve as a fundamental indicator of overall testosterone status in the body. While free testosterone represents the fraction of testosterone available for immediate use by tissues, total testosterone encompasses both bound and unbound forms, providing a comprehensive assessment of circulating testosterone levels.

The Role of SHBG

Sex hormone-binding globulin (SHBG) plays a crucial role in regulating the bioavailability of testosterone. It binds to testosterone molecules, reducing the fraction of free testosterone. While variations in SHBG levels can influence free testosterone concentrations, significant deviations are relatively uncommon in the absence of underlying medical conditions or hormonal imbalances.

Current Research Insights

Recent studies support the notion that total testosterone levels correlate strongly with free testosterone levels in most individuals, particularly within the reference range of testosterone values. Consequently, routine testing for free testosterone may offer limited additional clinical utility for the majority of patients undergoing testosterone replacement therapy (TRT).

Cholesterol and Testosterone

Understanding the intricate relationship between cholesterol and testosterone synthesis is key, especially for those considering testosterone replacement therapy (TRT). Cholesterol serves as a fundamental building block for testosterone, illustrating the vital link between these two elements within the body.

Despite concerns regarding TRT potentially leading to dyslipidemia, a condition characterized by an unhealthy balance of lipids in the bloodstream, recent research indicates that when TRT is correctly managed, it tends to have neutral or even beneficial effects on lipid profiles, including cholesterol levels. This insight is supported by findings from studies such as those conducted by Traish et al., 2017, and Corona et al., 2017.

Clinical Implications

Our decision to focus on total testosterone, along with a comprehensive metabolic panel (CMP), complete blood count (CBC), estradiol, and prostate-specific antigen (PSA) testing, reflects our commitment to efficient and evidence-based patient care. By emphasizing clinically relevant markers, minimizing unnecessary testing and patient expenditures, we strive to optimize diagnostic accuracy while streamlining the testing process for our patients.

 

 

References:
  • Vermeulen A, Verdonck L, Kaufman JM. A critical evaluation of simple methods for the estimation of free testosterone in serum. J Clin Endocrinol Metab. 1999 Oct;84(10):3666-72.
  • Ly LP, Handelsman DJ. Empirical estimation of free testosterone from testosterone and sex hormone-binding globulin immunoassays. Eur J Endocrinol. 2005 Mar;152(3):471-8.
  • Traish AM, Haider A, Haider KS, Doros G, Saad F. Long-term testosterone therapy improves cardiometabolic function and reduces risk of cardiovascular disease in men with hypogonadism. J Cardiovasc Pharmacol Ther. 2017 Jul;22(4):414-33.
  • Corona G, Rastrelli G, Maseroli E, et al. Effects of testosterone replacement therapy on lipid profile in hypogonadal men: a systematic review and meta-analysis. Eur J Endocrinol. 2017 Mar;176(3):269-83.
Category: Testosterone