Hormones
Sex Hormone Binding Globulin (SHBG)
Also known as: Sex Hormone-Binding Globulin
Reference ranges by source
Published adult intervals: 13, from 4 named sources, shown in nmol/L.
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About Sex Hormone Binding Globulin (SHBG)
An SHBG blood test measures the level of a protein called sex hormone binding globulin (SHBG) in a sample of your blood. SHBG is made mostly in your liver. It binds (attaches) to sex hormones such as testosterone, dihydrotestosterone, and estrogen and helps control how much of these hormones are active in your body.
All of the sex hormones in your blood are either bound to proteins or unbound (free). Free sex hormones work with your tissues, helping with a variety of bodily functions including bone and muscle growth and reproductive health. Sex hormones that are bound to proteins, such as SHBG, however, cannot work with your tissues.
An SHBG test is most often done if you have signs and/or symptoms of having too much or too little testosterone. Though often considered a male sex hormone, testosterone is present in females in smaller amounts. In both sexes, it helps control your sex drive and contributes to muscle and bone growth.
Main source: MedlinePlus ↗
Useful for
Help check for too little testosterone in adult males who have symptoms of low testosterone.
Help check for too much testosterone in adult females who have symptoms of high testosterone.
Help diagnose some hormonal disorders such as polycystic ovary syndrome (PCOS), a condition that affects the female reproductive system. An SHBG test alone cannot diagnose this condition, but it can help providers make a diagnosis when paired with other test results.
Monitor treatments for hormonal disorders such as PCOS.
Help diagnose early puberty in children. Normally, SHBG levels are high in all children. The high levels prevent sex hormones from affecting body tissues. If SHBG levels are low, children may start puberty too early.
Main source: MedlinePlus ↗
Interpretation
Your provider will usually look at your SHBG blood test results along with the results of a total testosterone test. This helps your provider estimate how much free testosterone is in your blood.
If your SHBG levels are too low, it means that more of your total testosterone is likely free and available for your body to use. SHBG can also be lower than normal in conditions such as an underactive thyroid, Cushing's syndrome, acromegaly, and obesity, or with testosterone use. Low SHBG is also linked to insulin resistance, and in some people it may signal a higher chance of developing type 2 diabetes over time.
Higher than normal SHBG can be seen in pregnancy, an overactive thyroid, liver scarring (cirrhosis), with oral estrogen treatment, and with some medicines.
It's also normal for SHBG levels to decrease with older age as the production of sex hormones also decreases.
For general wellness information only. Talk to a clinician about your specific results.
Main source: MedlinePlus ↗
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Sources
Last updated 2026-05-02
This page presents source-specific reference data and sourced explanations. For general wellness information only. This is not medical advice. For diagnosis or treatment of any condition, talk to a qualified clinician.