Hormone — Carrier Protein
SHBG (Sex Hormone Binding Globulin)
SHBG is a liver-produced protein that binds testosterone and estradiol in serum.
Reference range
Adult reference: ~10–80 nmol/L. Functional optimization context only — not a diagnostic assertion. Range varies by lab, age, and sex.
Why it matters
SHBG governs how much of total testosterone is biologically free. High SHBG drags down free testosterone even when total looks adequate; low SHBG raises free testosterone above what total alone would suggest. SHBG is influenced by liver health, insulin signaling, thyroid function, and protein intake — making it one of the most informative single markers in a longevity panel.
How REVRCEL clinicians read it
Out-of-range SHBG is rarely treated in isolation; it is read as a context marker that changes how testosterone, estradiol, and insulin signaling are interpreted.
Included in
- Hormone Optimization Panel
- Core Bloodwork
Common questions
What does high SHBG mean?
High SHBG binds more testosterone, lowering free testosterone. It can be driven by liver health, low insulin, hyperthyroidism, or genetics.
What does low SHBG mean?
Low SHBG raises free testosterone relative to total. It is often associated with insulin resistance, obesity, or hypothyroidism.
Related biomarkers
Statements have not been evaluated by the FDA. This page is educational and is not medical advice.