Low Testosterone: Free vs. Total Testosterone Levels

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Testosterone is a vital hormone for men, supporting essential functions such as regulation of fat distribution and enhancing muscle and bone strength[1]. The Endocrine Society estimates low testosterone is found among 35% of men over the age of 45 years old, with increasing prevalence as men advance in age [2]. If you are experiencing low sex drive, fat accumulation, and fatigue, getting your testosterone levels tested can be the first step to treatment. The two primary ways that men’s hormones are evaluated is through a total and free testosterone test. Keep reading to learn the key differences between free and total testosterone and their role in enhancing your overall health.

About Low Testosterone

On average, testosterone will begin to decline gradually at the rate of 1% each year after you reach the age of 30. As your testosterone decreases, you may experience several symptoms. Symptoms suggestive of low T levels include:

  • Insomnia
  • Depression
  • Decline in sexual performance
  • Low body strength
  • Unexplained weight gain
  • Mood swings
  • Brain fog[3]
  • Reduction in muscle mass

Along with the symptoms mentioned above, low T levels may make you prone to chronic health conditions like infertility, diabetes, obesity, heart issues, metabolic syndrome, and osteoporosis.

What is Total Testosterone?

A total testosterone level is the total sum of all the testosterone in your bloodstream, including both bound and free testosterone. Of the two, free (or unbound) testosterone refers to the ones circulated in your body through blood and are not tied to proteins. Bound testosterone, on the other hand, refers to the testosterone that moves through the blood tied to albumin or SHBG – Sex Hormone Binding Globulin. A total testosterone test is the most common and often only hormone evaluation to be performed by your physician if hypogonadism is suspected.

What is Low Free Testosterone?

Free testosterone refers to unbound testosterone that is ready for immediate use by the body. Although SHBG acts as a transporter for hormones, our cells cannot use the testosterone bound to SHBG proteins until they are released. SHBG serves to transport and circulate hormones in the blood, controlling timing of the use of hormones by cells. Of note, the majority of men’s testosterone is bound and unavailable for immediate use. Free testosterone only accounts for approximately 2% – 5% of all testosterone. Similarly, bioavailable testosterone refers to testosterone that is either free or weakly bound to albumin, which more readily releases testosterone at cell sites for use.

How Total and Free Testosterone Levels are Interconnected

If your total testosterone levels are low, your free testosterone will also be low. However, men can often have normal total testosterone levels, and still experience low levels of free testosterone. This is because our main binder of testosterone, SHBG increases for a number of reasons, including underlying health conditions such as hyperthyroidism or liver disease, or even with certain medications. We also see that simply aging causes an increase in SHBG, reducing the body’s ability to use the testosterone its produced.

Although a total testosterone reading is a useful screening tool, having a great amount of testosterone you cannot access provides little benefit. For the best understanding of your hormonal composition, a free testosterone calculation should also be included in hormone testing. Low free testosterone can causes all the symptoms of low T, despite a normal total testosterone reading [4].

Free Testosterone vs. Total Testosterone

If you are facing the symptoms of hypogonadism, such as fatigue and low libido, and got your testosterone levels tested, but you find that total testosterone is normal, it very well may be that the symptoms you are encountering are due to low free testosterone [5]. Studies also indicate free testosterone levels can predict hypogonadal symptoms beyond total testosterone levels alone.

How Testosterone Replacement Therapy Helps Men with Low Testosterone Levels

Both low free testosterone and low total testosterone can be successfully treated with Testosterone Replacement Therapy[6]. TRT is available in several forms and can restore hormonal levels to an optimal range[7]. The appropriate amount and frequency of bio-identical testosterone can be best determined by a specialized healthcare provider. The TRT programs offered by Revibe Men’s Health include close monitoring to track changes in your blood count, symptoms of hypogonadism, and testosterone levels. Based on these parameters, your treatment will be customized to achieve optimum results quickly.

The expected benefits of Testosterone Replacement Therapy are:

  • Enhanced sleep quality
  • Improved bone density[8]and muscle mass[9]
  • No mood swings[10]
  • Feeling more confident and being assertive
  • Better sex drive and libido[11]
  • Lower risk of developing heart issues and stroke[12]

Revibe Men’s Health: Enhance Your Performance and Health with Our Personalized Treatments

If you are experiencing symptoms related to low testosterone, schedule an appointment with the experts at Revibe Men’s Health. Our physicians can evaluate a complete hormonal panel and customize your treatment after a detailed analysis of your health history. We offer an array of personalized treatments for men to enhance their quality of life. Schedule an appointment with our low T experts today and feel the difference.

Reference Links:

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  2. Alvin Matsumoto, M.D., Caroline Davidge-Pitts, MBBCH, Glenn Cunningham, M.D., Maria George Vogiatzi, M.D., Maria Yialamas, M.D. – https://www.endocrine.org/patient-engagement/endocrine-library/hypogonadism
  3. Celec P, Ostatníková D, Hodosy J. On the effects of testosterone on brain behavioral functions. Front Neurosci. 2015 Feb 17;9:12. doi: 10.3389/fnins.2015.00012. PMID: 25741229; PMCID: PMC4330791. – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4330791/
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  7. Dr Earim Chaudry – https://www.manual.co/
  8. Snyder PJ, Kopperdahl DL, Stephens-Shields AJ, Ellenberg SS, Cauley JA, Ensrud KE, Lewis CE, Barrett-Connor E, Schwartz AV, Lee DC, Bhasin S, Cunningham GR, Gill TM, Matsumoto AM, Swerdloff RS, Basaria S, Diem SJ, Wang C, Hou X, Cifelli D, Dougar D, Zeldow B, Bauer DC, Keaveny TM. Effect of Testosterone Treatment on Volumetric Bone Density and Strength in Older Men With Low Testosterone: A Controlled Clinical Trial. JAMA Intern Med. 2017 Apr 1;177(4):471-479. doi: 10.1001/jamainternmed.2016.9539. Erratum in: JAMA Intern Med. 2017 Apr 1;177(4):600. doi: 10.1001/jamainternmed.2017.0968. Erratum in: JAMA Intern Med. 2019 Mar 1;179(3):457. doi: 10.1001/jamainternmed.2019.0249. PMID: 28241231; PMCID: PMC5433755. – https://pubmed.ncbi.nlm.nih.gov/28241231/
  9. Traish AM. Testosterone and weight loss: the evidence. Curr Opin Endocrinol Diabetes Obes. 2014 Oct;21(5):313-22. doi: 10.1097/MED.0000000000000086. PMID: 25105998; PMCID: PMC4154787. – https://pubmed.ncbi.nlm.nih.gov/25105998/
  10. Jung HJ, Shin HS. Effect of Testosterone Replacement Therapy on Cognitive Performance and Depression in Men with Testosterone Deficiency Syndrome. World J Mens Health. 2016 Dec;34(3):194-199. doi: 10.5534/wjmh.2016.34.3.194. Epub 2017 Jan 23. PMID: 28053949; PMCID: PMC5209560. – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5209560/
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  12. U.S. Department of Veterans Affairs – https://www.research.va.gov/currents/0815-5.cfm