SHBG
The protein that binds testosterone and estrogen — controls how much is biologically active.
What is it
SHBG is a protein produced by the liver that binds sex hormones (primarily testosterone and estradiol) in circulation. When SHBG is high, less hormone is biologically free; when SHBG is low, more hormone is free.
Why it's measured
SHBG is essential context for interpreting testosterone and estradiol values. Insulin resistance, thyroid status, and liver function all influence SHBG levels in research literature.
Reference range
Standard laboratory reference
Men: 10 – 57 / Women: 18 – 144 nmol/L
Reference ranges vary by laboratory. Your individual reference range will appear on your test report and should be interpreted by your physician in the context of your overall health profile.
Where does your number land?
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Drag to your own Sex Hormone Binding Globulin (SHBG) result.
Educational only, not a diagnosis. Ranges vary by laboratory. See which panel includes Sex Hormone Binding Globulin (SHBG).
What results may indicate
Elevated
Often seen with hyperthyroidism, certain medications, or aging in research literature. Reduces free hormone levels.
Lower
Has been associated with insulin resistance, metabolic syndrome, and obesity in published research.
These associations are general. They are not a personal diagnosis or prediction. Discuss your individual results with your physician in the context of your full health profile.
When it's measured
Measured alongside total testosterone for free testosterone calculation and metabolic context.
Related markers
Common questions
SHBG is a protein produced by the liver that binds sex hormones (primarily testosterone and estradiol) in circulation. When SHBG is high, less hormone is biologically free; when SHBG is low, more hormone is free.
It's one of the markers used to build a fuller picture of your health. On its own it tells you very little, so it's most informative when reviewed alongside related markers.
It's measured from a standard blood draw at Quest or LabCorp. Sex Hormone Binding Globulin (SHBG) is one of the markers included in the OPTML Apex Panel, where your results are read across systems and reviewed by a U.S.-licensed physician.
Reference ranges vary by laboratory, and a single value rarely tells the whole story. Review your result with a physician in the context of your other markers, symptoms, and history.
Sex Hormone Binding Globulin (SHBG) is one signal among many. Answer a few quick questions and we’ll point you to the panel that fits.
SHBG tracks closely with insulin sensitivity and body composition, both of which respond to resistance training. It is one of the markers where a change usually reflects a broader metabolic shift rather than anything acting on SHBG directly. If you want a structured place to start, the training library lists every programme we publish by days per week and equipment.
Measured in
A complete look at your heart, hormones, metabolism, inflammation, and longevity systems — drawn at Quest or LabCorp, reviewed by a U.S.-licensed physician.
Find the right panel →This information is for general educational purposes only and is not medical advice. Lab results alone are not intended to diagnose, treat, or cure any condition and do not replace the advice of a healthcare provider. OPTML does not offer medical advice, a diagnosis, medical treatment, or any form of medical opinion.
OPTML offers compounded semaglutide and tirzepatide, prescribed and overseen by U.S.-licensed physicians. Compounded drug products are not approved or evaluated for safety, effectiveness, or quality by the FDA. OPTML is not associated with, endorsed by, or affiliated with the manufacturers of FDA-approved branded weight-loss medications, and does not sell or supply those branded products. Anyone interested in an FDA-approved branded medication should consult a licensed healthcare provider or pharmacist. Individual results vary; no specific result is promised, and weight management requires ongoing medical guidance.
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