Is high Sex Hormone-Binding Globulin (SHBG) with normal Luteinizing Hormone (LH) and high total testosterone likely causing my low free testosterone and smaller testicles?

High SHBG with Normal LH is Likely NOT Causing Your Testicular Atrophy

Your smaller testicles are unlikely to be caused by high SHBG alone, since your LH is normal at 7.2 mIU/mL and your total testosterone is high—this indicates your testicles are functioning normally and responding appropriately to pituitary signals. 1, 2

Understanding Your Hormone Pattern

Your laboratory findings show a specific pattern that needs proper interpretation:

• High total testosterone with high SHBG results in low free testosterone because approximately 98% of testosterone is protein-bound, with the majority tightly bound to SHBG and rendered biologically unavailable 2
• Normal LH (7.2 mIU/mL) indicates your pituitary gland is not detecting testosterone deficiency and is not attempting to stimulate your testicles more than normal 1
• High SHBG can be misleading because it artificially elevates total testosterone measurements while the biologically active free testosterone remains low 2, 3

Why Your Testicles Are Likely Normal Size

The key diagnostic clue is your normal LH level:

• If your testicles were truly atrophying or failing, your LH would be elevated (typically >9-10 mIU/mL) as your pituitary attempts to compensate for reduced testicular function 1
• Normal LH with high total testosterone indicates adequate testicular steroidogenesis—your testicles are producing testosterone normally 1
• Testicular atrophy from primary hypogonadism causes elevated LH and FSH, which you do not have 1

What May Actually Be Happening

Your perceived smaller testicle size could be due to:

• Subjective perception or normal anatomical variation rather than true pathological atrophy 1
• Conditions affecting SHBG production (thyroid disorders, liver disease, medications, obesity) rather than testicular pathology 1, 3, 4
• Age-related changes in SHBG, which increases with aging and can create this exact hormone pattern 5, 6

Critical Next Steps for Accurate Diagnosis

You must measure free testosterone by equilibrium dialysis (the gold standard method) to determine if you truly have hypogonadism: 1, 2

1. Obtain morning (8-10 AM) free testosterone by equilibrium dialysis—this is essential because calculated free testosterone is prone to error when SHBG is abnormal 2
2. Avoid direct immunoassay methods for free testosterone as they have limited reliability and should not be used for clinical decision-making 2
3. Measure FSH in addition to your LH to fully evaluate testicular function—both should be normal if your testicles are healthy 1
4. Investigate causes of elevated SHBG: thyroid function tests, liver function tests, and assessment for medications or conditions affecting SHBG production 1, 3, 4

Common Pitfalls to Avoid

• Do not assume hypogonadism based solely on low calculated free testosterone when SHBG is elevated—you need equilibrium dialysis measurement 2
• Do not start testosterone replacement therapy without confirming true hypogonadism with at least 2 separate morning measurements of free testosterone by equilibrium dialysis 1, 2
• Do not ignore the normal LH—this is strong evidence against primary testicular failure 1
• Recognize that SHBG concentrations vary widely (nearly 20-fold range in clinical populations) and high SHBG alone does not indicate testicular pathology 5

When to Suspect True Testicular Pathology

You would need both of the following to indicate testicular atrophy:

• Elevated LH and FSH (indicating pituitary compensation for testicular failure) 1
• Low total testosterone AND low free testosterone by equilibrium dialysis on at least 2 separate morning measurements 1, 2

Your current hormone profile (high total T, normal LH) does not support testicular atrophy as the cause of your symptoms. 1, 2