What Causes High SHBG? Understanding the Factors Behind Sex Hormone-Binding Globulin Imbalance

If you’ve been digging into hormone health—especially around testosterone—you may have come across sex hormone-binding globulin (SHBG). This important protein plays a central role in how hormones like testosterone and estrogen are transported and accessed in the body. When SHBG levels become too high, it can affect how much free, bioavailable testosterone your body actually has, even if your total testosterone levels are normal. This issue can impact both men and women, often causing symptoms that lead people to explore solutions like testosterone replacement therapy.

In this article, we’ll break down what causes high SHBG, what it means for your health, and what to consider if your labs show elevated levels.

What Is SHBG?

SHBG is a glycoprotein produced mainly in the liver. Its primary function is to bind to sex hormones—especially testosterone and estrogen—and carry them through your bloodstream. When testosterone is bound to SHBG, it becomes inactive. Only unbound or "free" testosterone is available to enter cells and do its job—whether that's regulating libido, supporting muscle mass, or maintaining mood and energy.

If your SHBG is too high, even normal or high total testosterone levels may not be enough to maintain proper hormonal function. This can lead to signs of low testosterone despite what the top-line lab results suggest.

Common Causes of High SHBG

SHBG levels are influenced by many factors—some are temporary, and others are more chronic. Here's a breakdown of common causes:

1. Aging

As we age, SHBG levels naturally increase. This is part of the reason why both men and women experience hormonal changes as they get older, including reduced free testosterone.

2. Liver Health

Since SHBG is made in the liver, any changes in liver function can impact production. Liver disease, including hepatitis or fatty liver disease, may elevate SHBG levels.

3. Thyroid Function

Hyperthyroidism, or an overactive thyroid, can significantly raise SHBG. This is because thyroid hormones stimulate SHBG production in the liver.

4. Hormonal Medications

Certain medications, especially oral contraceptives or estrogen therapies, can boost SHBG. This is more common in women but can affect anyone undergoing hormone therapy.

5. High Estrogen Levels

An excess of estrogen—whether natural or through medications—can increase SHBG production. This is one reason SHBG is often higher in women than in men.

6. Nutritional Factors

Diet can play a role. For example, low protein intake, excess alcohol, or high fiber diets (in excess) may raise SHBG. In contrast, some studies suggest high insulin levels (from diets high in refined carbs) may reduce SHBG.

7. Genetics

Some individuals may naturally have higher SHBG levels due to genetic variations. While this isn't something that can be changed, it’s important to know if it’s part of your baseline.

8. Certain Health Conditions

Conditions like anorexia, HIV, or hypogonadism can all affect SHBG levels. Chronic illness and inflammation may also contribute.

Symptoms of High SHBG (and Low Free Testosterone)

Because SHBG binds testosterone, high levels can mimic the symptoms of low testosterone, including:

• Fatigue or low energy
• Decreased libido
• Brain fog or difficulty concentrating
• Loss of muscle mass
• Increased body fat
• Mood changes, including irritability or depression

In women, high SHBG can also impact fertility and menstrual regularity.

How SHBG Is Diagnosed

SHBG is typically measured through a blood test. However, evaluating SHBG alone isn’t enough. Most practitioners will also test for:

• Total testosterone
• Free testosterone
• Albumin (another binding protein)
• Estradiol
• Thyroid levels (TSH, T3, T4)
• Liver function tests

By analyzing these values together, a provider can better understand your hormonal picture and determine whether high SHBG is affecting your symptoms.

Managing High SHBG

Treatment depends on the underlying cause. In many cases, managing SHBG involves addressing lifestyle, nutritional, or medical factors:

• Improving liver health through alcohol reduction, weight management, or treating liver disease
• Balancing thyroid function if hyperthyroidism is present
• Modifying medications if possible
• Optimizing testosterone via lifestyle or medical therapy

In some cases, testosterone replacement therapy (TRT) may be appropriate—particularly if free testosterone is low and symptoms are present. TRT can help "outcompete" SHBG, ensuring more testosterone is available for your body to use.

The Bottom Line

High SHBG can make hormone optimization more complex, but it’s not insurmountable. Understanding what causes high SHBG is the first step in identifying whether it’s affecting your health and well-being. With proper testing and guidance, it’s possible to restore hormonal balance and feel your best again.

AlphaMD is a telehealth provider specializing in hormone optimization for both men and women. Our team takes a holistic, personalized approach to testosterone and SHBG-related concerns—all through convenient online consultations and direct-to-door medication delivery. If you suspect high SHBG or hormonal imbalance is affecting your health, we’re here to help you explore your options with evidence-based care.