A protein that carries sex hormones in your blood and helps explain free versus total levels.
Sex hormone-binding globulin, or SHBG, is a protein made mainly by the liver that carries sex hormones, including testosterone and estradiol, through the blood. Hormones bound to SHBG are held in reserve, while the unbound fraction is active.
SHBG shapes how much of your sex hormones is actually available to tissues. Because it binds testosterone tightly, a high or low SHBG can change the picture even when total testosterone looks normal.
Low SHBG, often seen with excess weight, insulin resistance, or an underactive thyroid, raises the active testosterone fraction. High SHBG, seen in pregnancy, an overactive thyroid, or liver disease, lowers it. SHBG is used to calculate free and bioavailable testosterone.
Aniva reads your result against research-backed ranges, not just the lab's wide normal. The reference shown below is specific to this biomarker.
Sex dependent. Guidance only and assay dependent. Ranges vary by lab.
| Group | Reference range |
|---|---|
| Women | ~20 to 130 nmol/L |
| Men | ~18 to 55 nmol/L |
Source: LOINC 13967-5. Confirm against your own laboratory's range.
Your SHBG, read with total testosterone, helps estimate how much active testosterone you have. It adds important context for symptoms of high or low androgens and for metabolic health.
SHBG rises with oestrogen, including the pill, pregnancy, and an overactive thyroid, and falls with excess weight, insulin resistance, and an underactive thyroid. Interpreting testosterone without SHBG can be misleading.
Best read together with total testosterone, and used to calculate free and bioavailable testosterone. Albumin is sometimes included in that calculation.
What do high or low SHBG results mean? High SHBG can reduce free hormones; low SHBG can increase them. Context with other tests helps explain symptoms.
Do I need to fast for an SHBG test? No. Fasting is not required unless your clinician bundles it with tests that need fasting.
What can affect SHBG levels? Estrogen or androgen medicines, thyroid status, liver disease, pregnancy, weight, insulin resistance, and high-dose biotin can all affect results.
How often should I test SHBG? Test when symptoms change or when starting, stopping, or adjusting hormone or thyroid treatment. Your clinician will guide timing.
How long do results take? Results are usually ready in about 7 days.
What should I discuss with my clinician? Share symptoms, all medicines, contraception, and supplements (especially biotin). Ask whether to calculate free testosterone or estradiol and check thyroid or liver markers.
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