Testosterone Replacement Therapy (TRT): Understanding the Testing Process and the Difference Between Total and Free Testosterone

Testosterone Replacement Therapy (TRT) has gained attention as a possible solution for men grappling with symptoms of low testosterone such as fatigue, reduced libido, and loss of muscle mass. One key factor in determining whether TRT is appropriate is accurate lab testing. At Simply Wellness, we prioritize a thorough approach to testosterone measurement—evaluating the difference between Total and Free Testosterone—to ensure we identify any underlying hormonal imbalances accurately.

Step 1: Comprehensive Blood Testing

Why Testing Matters Before starting any form of hormone therapy, the first step is to test your hormone levels. A simple blood test can provide valuable insights into whether you have low testosterone (often referred to as “Low T”). However, total testosterone alone doesn’t always tell the whole story. What We Measure

• Total Testosterone: This measures the total amount of testosterone circulating in your bloodstream. However, a portion of this testosterone is bound to proteins like SHBG (Sex Hormone-Binding Globulin) and albumin, rendering it “inactive.”
• Free Testosterone: This is the fraction of testosterone not bound to SHBG or albumin, making it the biologically active form that can exert effects on various tissues in the body.

Step 2: Interpreting Total vs. Free Testosterone

Total Testosterone

• A typical reference range might be somewhere around 300 to 1,000 ng/dL, although it varies by lab.
• If your total testosterone is below the lower threshold, it often (but not always) indicates you could benefit from TRT if symptoms are present.

Free Testosterone

• Free T is a smaller fraction of the total testosterone.
• It’s considered more reflective of your actual hormonal status because free T is the testosterone that’s immediately available to the body’s tissues.

High SHBG and “Normal” Total Testosterone A common scenario we see is someone whose total testosterone is in the “normal” range, but they still experience Low T symptoms—fatigue, low libido, or difficulty building muscle. In these cases, high levels of SHBG bind a significant amount of the total testosterone, reducing the free testosterone available. Despite “normal” total testosterone levels, the biologically active hormone might be insufficient to support optimal health and vitality.

Step 3: Comprehensive Evaluation of Symptoms

Symptoms Aren’t One-Size-Fits-All Numbers on a lab result are only part of the story. We also take into account:

• Fatigue and Low Energy
• Changes in Mood (Irritability, Depression, Anxiety)
• Reduced Muscle Mass and Strength
• Increased Body Fat
• Decreased Libido and Sexual Function

Even if lab values fall within normal limits, persistent symptoms may still be indicative of a hormonal imbalance. That’s why, at Simply Wellness, we pair thorough lab testing with an in-depth review of your symptoms, medical history, and lifestyle factors.

Step 4: Crafting a Personalized Treatment Plan

If our assessment suggests you could benefit from TRT, we discuss the potential risks and benefits in detail. Key aspects of our approach at Simply Wellness include:

1. Customized Dosage
   • We base your treatment regimen on both lab results (including free T) and your personal symptom profile.
2. Variety of Treatment Methods
   • Options may include injections, topical gels, patches, or pellets, depending on your preferences and clinical needs.
3. Lifestyle Optimization
   • We often recommend complementary strategies like tailored nutrition plans, strength training, and stress management to maximize your results and overall well-being.
4. Ongoing Monitoring
   • We periodically re-check hormone levels and assess symptom changes, adjusting your plan if needed.

Why Understanding SHBG Is Important

The Role of SHBG Sex Hormone-Binding Globulin (SHBG) is a protein that binds to sex hormones—including testosterone—making them unavailable for immediate use by the body. High SHBG levels can significantly reduce free testosterone, which is why some men experience classic low testosterone symptoms despite having total levels within the normal range. What Causes Elevated SHBG?

• Age: SHBG tends to increase as men get older.
• Certain Medical Conditions: Liver disease, hyperthyroidism, and other health concerns can influence SHBG levels.
• Lifestyle Factors: Diet, exercise, and stress can also affect SHBG production.

Having a clear understanding of SHBG helps providers craft a more accurate treatment plan and ensure that therapy targets free testosterone levels effectively.

Conclusion

Understanding the difference between total testosterone and free testosterone, as well as the impact of SHBG, is crucial for identifying and treating Low T effectively. High SHBG can mask a genuine deficiency if only total testosterone is measured, leaving many men underdiagnosed. At Simply Wellness, our patient-centered process includes comprehensive lab testing, careful evaluation of symptoms, and a holistic approach to optimizing health. If you suspect low testosterone or are curious whether TRT might help, we encourage you to consider a thorough hormone panel and a specialized consultation.

References and Sources

1. Bhasin, S., Brito, J. P., Cunningham, G. R., et al. (2018). Testosterone therapy in men with hypogonadism: An Endocrine Society clinical practice guideline*. The Journal of Clinical Endocrinology & Metabolism, 103(5), 1715–1744.
2. Morales, A., Schulman, C., Tostain, J., & Wu, F. C. W. (2006). Testosterone deficiency syndrome (TDS) needs to be named appropriately—The importance of accurate terminology for accurate diagnosis and treatment. The Journal of Sexual Medicine, 3(6), 1071–1076.
3. Khosla, S., Melton III, L. J., Atkinson, E. J., & O’Fallon, W. M. (1998). Relationship of serum sex steroid levels and bone turnover markers with bone mineral density in men and women: A key role for bioavailable estrogen. The Journal of Clinical Endocrinology & Metabolism, 83(7), 2266–2274.
4. Wang, C., Nieschlag, E., Swerdloff, R., et al. (2008). Investigation, treatment, and monitoring of late-onset hypogonadism in males. The Aging Male, 11(1), 5–12.
5. Westley, C. J., & Tremellen, K. P. (2021). Testosterone deficiency in men: Pathophysiology and diagnosis. Australian Family Physician, 50(9), 647–652.

Disclaimer: The information provided in this blog post is for educational purposes only and should not be taken as medical advice. Always consult a qualified healthcare provider for personalized guidance regarding diagnosis and treatment.