Why is Sex Hormone-Binding Globulin (SHBG) High? Causes, Symptoms, and What to Do

Sex hormone-binding globulin (SHBG) is a protein made by your liver that binds to sex hormones, such as testosterone and estrogen, and transports them in your blood. If your SHBG levels are high, it can affect the amount of free (active) hormones available in your body. Understanding why SHBG levels might be high, what symptoms to look for, and when to see a doctor can help you manage your health effectively.

What is SHBG?

SHBG is a protein that binds tightly to three sex hormones found in both men and women: testosterone, dihydrotestosterone (DHT), and estradiol (an estrogen). Its main role is to transport these hormones in the bloodstream and regulate their access to tissues. By binding to these hormones, SHBG controls the amount of free, active hormones available for the body to use.

Why does SHBG matter?

The balance of SHBG is crucial because it affects the levels of free hormones in your body. Free hormones are the ones not bound to SHBG and are available to act on your body's tissues. If SHBG levels are too high, it can lead to lower levels of free testosterone or estrogen, which might affect various bodily functions. Clinicians often measure SHBG along with total testosterone to estimate the levels of free hormones.

Causes of high SHBG levels

Several factors can lead to high SHBG levels:

• Age: As people age, SHBG levels tend to increase naturally.
• Liver disease: Since SHBG is produced in the liver, liver conditions can affect its levels.
• Hormonal conditions: Conditions like hyperthyroidism (an overactive thyroid) can raise SHBG levels.
• Medications: Certain medications, including oral contraceptives and hormone replacement therapies, can increase SHBG levels.
• Genetic factors: Some people might have a genetic predisposition that affects SHBG production.

Symptoms of high SHBG

High levels of SHBG can lead to symptoms related to low free testosterone or estrogen. These may include:

• For men: Reduced libido, erectile dysfunction, fatigue, and loss of muscle mass.
• For women: Irregular menstrual cycles, reduced libido, and mood changes.

How SHBG levels are interpreted

SHBG levels are measured in nanomoles per liter (nmol/L). The interpretation of these levels can vary based on age, sex, and other factors. Here are some general figures:

• For men, SHBG levels typically range from 18 to 54 nmol/L.
• For women, SHBG levels can range from 18 to 144 nmol/L.

These levels are often interpreted together with total testosterone levels to estimate the amount of free hormone available.

Frequently asked questions

What can cause SHBG levels to increase suddenly? Sudden increases in SHBG can be caused by changes in medication, the onset of a thyroid condition, or liver issues. Consulting with a healthcare provider can help identify the cause.

Can lifestyle changes affect SHBG levels? Yes, lifestyle factors such as diet, exercise, and managing stress can influence hormone levels and may impact SHBG levels indirectly.

Is high SHBG a sign of a serious health issue? High SHBG levels can be associated with certain health conditions, but they are not always indicative of a serious problem. It is important to discuss your results with a healthcare provider.

When to see a doctor

If you receive a lab result showing high SHBG levels, it is a good idea to consult with a healthcare provider, especially if you are experiencing symptoms like fatigue, libido changes, or menstrual irregularities. A doctor can help determine if further testing or a treatment plan is necessary.

Disclaimer: This article is for informational purposes only. Always consult with your healthcare provider for medical advice and decisions.