SHBG and Men’s Sexual Health: What Does Your SHBG Level Tell You?

If you have had a testosterone test, you may have noticed another number on the report called SHBG. But what is SHBG, and what does it actually tell you about your testosterone, libido, erections and overall sexual health?

SHBG stands for sex hormone-binding globulin. It is a protein produced mainly by the liver that binds to testosterone and other sex hormones in the bloodstream. Because SHBG affects how much testosterone is available in its unbound form, it can help explain why total testosterone and free testosterone do not always tell the same story.

For men being evaluated for low testosterone, low libido or sexual difficulties, SHBG can provide important context, particularly when the total testosterone result is borderline or does not match the symptoms.

What Does SHBG Do?

Testosterone circulates in the blood in different forms. Some is strongly bound to SHBG, some is loosely bound to albumin, and a small amount remains free. SHBG influences the balance between these forms.

This is why two men with similar total testosterone levels can sometimes have different free testosterone levels.

A man with relatively high SHBG may have less free testosterone despite having a total testosterone level that appears normal. Conversely, a man with low SHBG may have a relatively low total testosterone level while his free testosterone is less affected.

So, when interpreting testosterone, SHBG can sometimes explain what the total testosterone number alone cannot.

Does SHBG Affect Libido?

SHBG does not directly determine your sex drive, but it can influence testosterone availability, and testosterone plays an important role in male sexual desire.

Clinically significant testosterone deficiency can be associated with reduced libido, fewer spontaneous sexual thoughts and changes in sexual function. However, low libido is not automatically caused by testosterone or SHBG.

Stress, anxiety, depression, relationship difficulties, poor sleep, obesity, medications and other medical conditions can all reduce sexual desire.

This is why a low libido should not be diagnosed simply by looking at an SHBG result.

Can SHBG Affect Erections?

SHBG can be relevant when evaluating testosterone status, but SHBG is not a direct test for erectile dysfunction.

An erection depends on blood flow, nerves, hormones, sexual stimulation and psychological factors. A man can have normal testosterone and SHBG and still experience erectile dysfunction.

Likewise, a man with low testosterone may experience reduced libido and sexual difficulties, but testosterone may not be the only reason for his erection problem.

If a man says, "My testosterone is normal but I cannot stay hard during sex," the evaluation should consider other factors such as performance anxiety, cardiovascular health, medications and psychological or relationship issues.

What Does High SHBG Mean?

High SHBG means more testosterone may be bound to SHBG, potentially reducing the amount of free testosterone available.

Higher SHBG can occur with factors such as ageing, hyperthyroidism, certain liver conditions, some medications and low body weight.

High SHBG becomes particularly relevant when total testosterone looks normal but free testosterone is unexpectedly low.

For example, a man may have a total testosterone result that appears acceptable but still have symptoms consistent with low testosterone. In that situation, assessing SHBG and free testosterone can provide additional information.

What Does Low SHBG Mean?

Low SHBG is commonly associated with obesity, insulin resistance and metabolic problems. It can also occur with hypothyroidism and certain other conditions.

Low SHBG can make total testosterone appear lower without necessarily producing the same reduction in free testosterone.

This is one reason that a low total testosterone result should not automatically be interpreted as testosterone deficiency without considering the rest of the hormone profile.

Is High or Low SHBG Worse?

Neither is automatically worse.

The goal is not to have the highest or lowest possible SHBG. The important question is why SHBG is abnormal and how it is affecting the overall testosterone picture.

High SHBG with low free testosterone can have a different significance from low SHBG associated with obesity or insulin resistance.

The number needs context.

“When we look at a hormone report, one number rarely tells the complete story. SHBG can change how we interpret testosterone, but the real question is whether the complete hormonal picture matches the man's symptoms and overall health.” - Dr. Sudhir Bhola

SHBG and Free Testosterone: Why Are They Connected?

This is one of the most important reasons SHBG is measured.

Total testosterone tells you how much testosterone is circulating overall. Free testosterone tells you how much testosterone is not tightly bound to proteins. SHBG influences the relationship between the two.

Therefore, if a man has symptoms such as low libido or reduced sexual function but his total testosterone is borderline, SHBG and free testosterone may provide useful additional information.

The American Urological Association considers total testosterone the primary diagnostic measurement but recognizes that free testosterone can be useful in selected men with borderline total testosterone or significant symptoms.

Can High SHBG Cause Low Testosterone Symptoms?

It can contribute to a lower free testosterone level, but high SHBG by itself does not diagnose testosterone deficiency.

A proper diagnosis requires compatible symptoms together with consistently low testosterone measurements. The Endocrine Society recommends confirming low testosterone with accurate repeat morning testing rather than diagnosing testosterone deficiency from a single result.

Symptoms such as low libido, erectile difficulties, low energy and reduced muscle mass can occur with testosterone deficiency, but they can also have many other causes.

Can Low SHBG Mean Your Testosterone Is Actually Fine?

Yes.

A man with low SHBG may have a relatively low total testosterone result while his free testosterone is not proportionately reduced.

This is why the question "Is my testosterone normal?" can sometimes be more complicated than looking at total testosterone alone.

The more useful assessment may involve looking at total testosterone + SHBG + free testosterone + symptoms.

When Should SHBG Be Tested?

SHBG does not necessarily need to be tested in every man who checks testosterone.

It can be particularly useful when total testosterone is borderline, symptoms do not match the total testosterone result, or a condition that can alter SHBG is suspected.

Depending on the situation, a doctor may also consider LH, FSH, prolactin, thyroid function and other tests to understand the underlying cause of hormonal or sexual symptoms.

The purpose of testing should be to answer a clinical question rather than simply collecting more numbers.

What Does SHBG Actually Tell You About Your Sexual Health?

SHBG does not tell you whether you will have strong erections, high libido or good sexual performance.

Instead, it can help explain your testosterone status.

It may show why total testosterone and free testosterone do not appear to match and can provide clues about conditions affecting hormone metabolism.

For example, one man may have high SHBG and low free testosterone. Another may have low SHBG associated with obesity and metabolic health problems. A third may have normal SHBG but erectile dysfunction caused primarily by performance anxiety.

Their treatment should not be the same.

Should You Worry About an Abnormal SHBG Result?

Not necessarily.

An SHBG result outside the laboratory reference range is a finding that needs interpretation, not a diagnosis by itself.

The result should be considered alongside total testosterone, free testosterone, symptoms, medical history and other relevant health factors.

Trying to correct SHBG without understanding why it is abnormal may also miss the underlying issue.

SHBG, Testosterone and Sexual Health: The Bottom Line

SHBG is an important part of the testosterone picture, but it is not a direct measure of sexual health.

High SHBG can be associated with lower free testosterone, while low SHBG can change the relationship between total and free testosterone. However, neither high nor low SHBG automatically means that a man has poor libido or erectile dysfunction.

If you are experiencing low libido, erectile dysfunction, reduced energy, loss of strength or other symptoms associated with low testosterone, SHBG may be useful as part of a broader evaluation.

The most meaningful assessment is not one number. It is the combination of symptoms, total testosterone, free testosterone, SHBG and the individual's overall health.

Frequently Asked Questions

What is SHBG in a testosterone test?

SHBG stands for sex hormone-binding globulin. It is a protein that binds testosterone and influences the amount of testosterone that remains free or readily available.

Does high SHBG cause low free testosterone?

High SHBG can be associated with lower free testosterone because more testosterone is bound to SHBG. The significance depends on the overall testosterone profile and the individual's health.

Does low SHBG mean low testosterone?

Not necessarily. Low SHBG can lower total testosterone without causing the same degree of reduction in free testosterone.

Can SHBG affect libido?

SHBG can indirectly affect libido by influencing testosterone availability, but SHBG itself is not a direct measure of sexual desire.

Can SHBG cause erectile dysfunction?

SHBG is not a direct cause or diagnostic test for erectile dysfunction. It may provide information about testosterone status, while ED can have hormonal, vascular, neurological, psychological and relationship-related causes.

Should SHBG be tested with testosterone?

It can be useful when total testosterone is borderline, symptoms do not match the testosterone result or a condition affecting SHBG is suspected.

What is more important, SHBG or free testosterone?

They provide different information. SHBG helps explain how testosterone is bound in the blood, while free testosterone estimates the portion that is not tightly bound. In selected men, considering both can help interpret testosterone status.