Sex Hormone-Binding Globulin (SHBG)
Sex hormone-binding globulin is a liver protein that binds testosterone and estradiol and regulates how much circulates in free form.
Unit: nmol/L · 12 slices · age and sex · 1 source
Filed under panels: Hormones · topics: Endocrine
Sex hormone-binding globulin (SHBG) is produced by the liver and binds circulating sex steroids, controlling the free (active) fraction. SHBG is measured here in nmol/L from the NHANES sex steroid hormone panel. Levels differ by sex and rise with age in many adults; they are also influenced by thyroid status, insulin, and body composition.
Population Distribution
Browse by Demographic
| Age (years) | male (nmol/L) | female (nmol/L) |
|---|---|---|
| 20-29 | 12.4–56.8 (25.9) | 17.3–170.9 (47.4) |
| 30-39 | 12.7–59.7 (27.8) | 21.9–148.9 (55.5) |
| 40-49 | 13.2–62.4 (30.2) | 20.6–139.8 (52.2) |
| 50-59 | 15.1–70.9 (34.8) | 18.3–111.5 (47.1) |
| 60-69 | 20.1–90 (40.9) | 20.5–121.8 (52) |
| 70+ | 23.9–100.4 (48.5) | 26–161.2 (65.2) |
Frequently Asked Questions
What does SHBG do?
SHBG binds testosterone and estradiol in the blood. The bound fraction is not immediately available to tissues, so SHBG levels influence how much free, active hormone circulates even when total hormone levels are unchanged.
Why does SHBG differ between people?
SHBG is shaped by sex, age, thyroid hormone, insulin levels, and body composition. Higher insulin tends to lower SHBG, while higher thyroid hormone tends to raise it, contributing to a broad population distribution.
How does NHANES handle hormone values below the detection limit?
When a result falls below the assay's lower limit of detection, NHANES replaces it with the detection limit divided by the square root of 2. For FSH, values below 0.30 mIU/mL were recoded as below detection and imputed the same way. In groups where many people have low concentrations, the lower percentiles can reflect this imputation rather than distinct measured values.