SHBG (Sex Hormone Binding Globulin)
This test measures sex hormone binding globulin (SHBG), a protein that regulates the amount of biologically active testosterone and estrogen available to the body.
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Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
What this test measures
Sex hormone-binding globulin (SHBG) is a protein manufactured primarily in the liver that transports testosterone and estrogen through the bloodstream. While bound to SHBG, these hormones are held in an inactive state and cannot enter cells to exert their effects. Only the unbound (free) fraction of testosterone or estrogen is immediately available for use by tissues.
SHBG therefore acts as a regulator of hormone availability. When SHBG levels are high, more testosterone and estrogen are sequestered in their bound form, reducing the amount of active hormone reaching muscles, bones, and reproductive tissues. When SHBG is low, a greater share of sex hormones remains unbound and biologically active. This balance has downstream effects on metabolism, reproductive function, energy levels, and body composition. The test is particularly valuable for clarifying situations where total testosterone appears normal but symptoms of deficiency or excess persist, since SHBG can explain the discrepancy between what the body produces and what the tissues actually receive.
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals experiencing symptoms of hormone imbalance, such as unexplained fatigue, changes in muscle mass, or altered mood
- Individuals being evaluated for hirsutism in women and for infertility, reduced libido or erectile dysfunction in men, particularly when androgen levels are within normal ranges
- Women suspected of having polycystic ovary syndrome (PCOS) or experiencing irregular periods, acne, or excess hair growth
- Individuals with metabolic conditions like obesity, insulin resistance, or type 2 diabetes that may affect hormone balance
- Those taking hormone therapy or medications that might influence sex hormone levels
- Individuals with thyroid disorders, as these conditions can significantly impact SHBG production
What to expect
Preparation
No special preparation is typically required for this test. Individuals should inform their healthcare provider about any medications, supplements, or hormone therapies they are taking, as these may affect results. The test can be performed at any time of day and does not require fasting.
Sample Type
This test requires a simple blood draw from a vein, typically in the arm.
Collection
The blood sample collection takes just a few minutes at the lab. A healthcare professional will clean the area, insert a small needle to draw blood into a tube, and apply a bandage afterward. Most individuals experience minimal discomfort.
Turnaround
Results are typically available within 1-2 business days after the lab receives the sample.
Understanding your results
Results are reported in nanomoles per liter (nmol/L). Because SHBG directly governs how much testosterone and estrogen are available in their active form, the result is most informative when evaluated alongside total and free testosterone (or estradiol) levels. A high SHBG reading paired with low free testosterone, for example, may explain symptoms of hormonal insufficiency even when total testosterone appears within range. Healthcare providers consider SHBG alongside clinical symptoms, liver function, thyroid status, and other hormonal markers to assess overall hormonal balance.
| Population | Reference Range | Notes |
|---|---|---|
| Adult Males | 10-57 nmol/L | Men's SHBG levels usually increase with age as testosterone levels naturally decline |
| Adult Females (Non-pregnant) | 18-144 nmol/L | Women typically have higher SHBG levels than men |
| Pregnant Women | Elevated above normal range | SHBG is also produced by placental tissue and values will be elevated during pregnancy |
Reference ranges shown are general guidelines. Your lab report will include the specific reference range used by the laboratory that processed your sample, which is the authoritative range for interpreting your results.
What does a “Low” result mean?
Decreased SHBG levels can be associated with obesity, hyperinsulinemia, hypothyroidism and growth hormone excess, as well as with glucocorticoids, androgens, and progestins. Low serum SHBG levels are considered a biomarker of abnormal metabolism and are related to insulin resistance, compensatory hyperinsulinemia and abnormalities in glucose and lipid metabolism. Lower serum SHBG levels are associated with the risk of PCOS, and low SHBG means more free testosterone circulating in the bloodstream, which can worsen PCOS symptoms like hirsutism (excess hair growth), acne, and irregular periods. Low levels may also indicate increased risk for metabolic syndrome and type 2 diabetes.
What does a “High” result mean?
Increased SHBG levels can be associated with anorexia, pregnancy, aging, growth hormone deficiency, androgen deficiency, hyperthyroidism, liver disease, hyperprolactinemia, active porphyria and also with estrogens. Thyrotoxicosis increases SHBG concentrations, and elevated levels may suggest tissue thyrotoxicosis in certain clinical situations. Higher SHBG levels typically mean that less free testosterone and estrogen are available for the body to use, which may contribute to symptoms like reduced libido, fatigue, or decreased muscle mass. In the long term, SHBG on the high end of the normal range can have a protective effect on the heart and may decrease prostate cancer risk, but it may be linked to weakened bones in elderly individuals.
Privacy & confidentiality
All test orders are authorized and results reviewed by an independent, board-certified physician who is not the patient's personal doctor. Your SHBG test results are completely confidential and handled with the utmost discretion. Results are <u>not reported to your doctor</u> unless you specifically request it, and they are <u>not part of your medical records</u> maintained by healthcare providers. The test is <u>not covered by insurance</u>, so there are no insurance claims or explanations of benefits that could reveal your testing. Results are <u>not on insurance statements</u> or shared with employers, family members, or government agencies. The testing process is designed to protect your privacy at every step. You can order the test online discreetly, visit any lab location without an appointment, and receive your results securely through an encrypted online portal. Many individuals choose private hormone testing to understand their health status confidentially, whether for personal knowledge, before consulting with a healthcare provider, or to monitor changes over time without creating a medical record.
Frequently asked questions
Related tests
Testosterone, Total
Often ordered together with SHBG to calculate free testosterone and assess overall androgen status
View TestTestosterone, Free
Measures biologically active testosterone that is not bound to SHBG or other proteins
View TestInsulin, Fasting
Insulin resistance can suppress SHBG production and is commonly evaluated alongside SHBG testing
View TestRelated conditions
Related articles
Testosterone Levels by Age: What Is Normal?
Read ArticleTotal Testosterone vs Free Testosterone: Which Test Do You Need?
Read ArticleTracking Testosterone: A Biohacker's Guide to Male Hormone Optimization
Read ArticleLast reviewed: April 2026
CPT Code: 84270
This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
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LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
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