SHBG — Sex Hormone Binding Globulin
SHBG binds sex hormones in the blood, so it helps explain how much of your testosterone is available to tissues — even when total testosterone reads normal.
SHBG (sex hormone-binding globulin) is a protein that binds testosterone and other sex hormones in the blood — bound hormones cannot work with your tissues, so SHBG helps explain how much of your total testosterone is actually available.
The biomarker
- Name: Sex Hormone-Binding Globulin (SHBG)
- Units: nmol/L
- Standard reference range: laboratory-specific — read your result against the range printed on your report (ranges vary by lab)
How to read your result
| Value | Interpretation |
|---|---|
| Below your lab's range | Has several possible explanations, including steroid or anabolic-steroid use — not a diagnosis; review with your clinician |
| Within your lab's range | Read together with total (and, if ordered, free) testosterone |
| Above your lab's range | Less of your total testosterone is available to tissues; has several possible explanations, including estrogen-containing medicines — review with your clinician |
What to ask about
- If low. Ask your clinician whether to check insulin resistance, weight-related factors and thyroid function.
- If high. Ask whether a free testosterone test would add information to your total testosterone.
- Clinician. Ask about endocrinology referral if SHBG is persistently abnormal.
Why this test is worth asking for
- Total testosterone measures bound and free hormone together; SHBG shows how much is bound and unavailable to tissues.
- You can have too little or too much free testosterone even when your total testosterone level is normal.
- A free testosterone test measures only the unattached form and may be ordered alongside SHBG.
Related protocols
- Zinc — Immune Mineral Status
- Urine ACR — Albumin-to-Creatinine Kidney Marker
- Uric Acid — Metabolic + Gout Marker
Sources
AgeGen lab guides are educational only. We do not provide medical diagnosis, prescribe brands, or recommend specific doses. Talk to a licensed clinician before changing your supplement or medication routine.
