Eterna Integrative Team
When hormone testing reveals high sex hormone-binding globulin (SHBG) levels, many patients find themselves confused about what this means for the big picture story of their overall health. This protein, produced primarily by the liver, plays a critical yet often misunderstood role in regulating hormone activity throughout the body. Understanding why SHBG rises and how elevated levels affect men versus women differently can help guide more effective treatment approaches.
What Is SHBG and Why Does It Matter?
Sex hormone-binding globulin is a transport protein that binds to sex hormones in the bloodstream, particularly testosterone and estrogen. When hormones attach to SHBG, they become biologically inactive and cannot interact with tissues. This binding serves as a regulatory mechanism, controlling how much “free” hormone remains available for your body to use.
The balance matters enormously. When SHBG levels climb too high, an excessive proportion of your sex hormones gets locked away in an inactive state. Even if your total testosterone or estrogen levels appear normal on lab work, high SHBG means fewer of these hormones can actually perform their biological functions. This disconnect between total hormone levels and bioavailable hormones explains why some patients experience symptoms of hormone deficiency despite seemingly adequate hormone production.
Common Causes of Elevated SHBG
Several conditions and factors can drive SHBG levels upward. Hyperthyroidism stands as one of the most significant causes, with excess thyroid hormone directly stimulating increased SHBG production in liver cells through complex metabolic pathways. Research shows that thyroid hormones increase SHBG indirectly by raising levels of hepatocyte nuclear factor-4α, a key regulator of liver metabolism.
Certain forms of liver disease present a paradox: while some liver conditions decrease SHBG production, cirrhosis can actually elevate SHBG levels despite damaged liver tissue. This appears to represent a compensatory response to altered hormone metabolism in cirrhotic livers.
Age plays a natural role in men, with SHBG levels rising approximately 40% in older age categories. This age-related increase contributes to the decline in bioavailable testosterone that many older men experience, even when total testosterone hasn’t dropped dramatically.
Severe calorie restriction or eating disorders like anorexia can push SHBG upward as the body’s metabolic state shifts. Oral contraceptives in women represent another common cause, with some studies showing SHBG levels increasing up to four-fold during birth control pill use. This effect stems from synthetic estrogen’s powerful influence on liver SHBG production.
How High SHBG Manifests Differently in Men and Women
The symptoms of elevated SHBG vary significantly between sexes, reflecting testosterone’s different roles in male versus female physiology.
High SHBG in Men
For men, elevated SHBG typically manifests as symptoms of testosterone deficiency, even when total testosterone measurements fall within normal ranges. The most common complaints include persistent fatigue, decreased libido, and erectile dysfunction. Research tracking 733 Chinese men over four years found that high SHBG levels independently predicted increased erectile dysfunction risk. Men with both low free testosterone and high SHBG faced the highest risk, with a 4.6-fold increased likelihood of developing erectile problems.
The mechanism is straightforward: when SHBG binds excessive amounts of testosterone, insufficient free testosterone remains available to maintain erectile function, muscle mass, and energy levels. Men may also experience difficulty building or maintaining muscle mass, as testosterone plays crucial roles in protein synthesis and muscle development. Depression and cognitive changes like brain fog can emerge as testosterone’s neurological effects diminish.
High SHBG in Women
Women with elevated SHBG often report low libido, irregular menstrual cycles, and fertility challenges. Because SHBG binds both testosterone and estrogen, high levels can reduce the bioavailability of both hormones. For women, even the relatively small amounts of testosterone they produce matter significantly for maintaining libido, energy, and overall vitality.
Some women may experience symptoms mimicking low estrogen, including mood changes, fatigue, and potential impacts on bone density over time. The hormonal picture becomes complex when oral contraceptives drive SHBG elevation, as synthetic hormones may partially compensate for reduced bioavailable natural hormones while still leaving some women symptomatic.
The PCOS Paradox: Why This Condition Differs
While this article focuses on high SHBG, it’s essential to understand that polycystic ovary syndrome (PCOS) typically presents with the opposite problem. Women with PCOS characteristically have low SHBG levels, not high. This occurs because insulin resistance and hyperinsulinemia—hallmarks of PCOS—suppress SHBG production by the liver.
The low SHBG in PCOS creates a vicious cycle: with less SHBG to bind testosterone, more testosterone remains free and biologically active, worsening the hyperandrogenism that defines PCOS. Meta-analyses involving thousands of women confirm that lower serum SHBG levels strongly associate with PCOS risk and may serve as both a biomarker for diagnosis and a therapeutic target.
However, a subset of PCOS patients may have normal or even elevated SHBG, particularly those with the “reproductive” phenotype characterized by high SHBG, low body mass index, and minimal insulin resistance. This underscores that PCOS exists on a spectrum, with distinct metabolic and reproductive subtypes.
Diagnosing and Addressing High SHBG
Testing for SHBG provides valuable information when symptoms suggest hormone imbalance despite normal total hormone levels. A simple blood test measures SHBG concentration, ideally alongside total and free testosterone and estradiol. For men experiencing erectile dysfunction or fatigue, and women facing low libido or irregular cycles, this comprehensive hormone panel can reveal whether high SHBG contributes to symptoms.
Treatment focuses on addressing the underlying cause. When hyperthyroidism drives elevated SHBG, treating the thyroid condition typically normalizes SHBG levels within weeks to months. For women whose oral contraceptives have significantly raised SHBG, switching to alternative contraceptive methods or adjusting formulations may help.
Dietary approaches that may help lower excessive SHBG include increasing protein intake and ensuring adequate healthy fat consumption. Some evidence suggests that maintaining higher protein diets associates with lower SHBG, though more research is needed. For individuals with very low body weight or restrictive eating patterns, gradually restoring healthy weight often brings SHBG back toward normal ranges.
In cases where high SHBG persists despite addressing obvious causes, functional medicine practitioners may explore liver health optimization, mitochondrial support, and targeted nutritional strategies to help restore hormonal balance. The goal is always to identify and treat root causes rather than simply suppressing symptoms.
When to Seek Professional Guidance
If you’re experiencing symptoms like persistent fatigue, low libido, erectile dysfunction, irregular periods, or difficulty maintaining muscle mass, comprehensive hormone testing including SHBG should be considered.
Working with an integrative medicine physician familiar with functional approaches to hormone balance can be particularly valuable when dealing with high SHBG. At Eterna Integrative, we utilize advanced diagnostic testing to identify root causes of hormonal imbalances and develop personalized treatment plans that address the whole person, not just isolated lab values.
High SHBG rarely exists in isolation—it typically signals underlying metabolic, thyroid, or liver issues that deserve attention. By understanding how elevated SHBG affects hormone availability differently in men and women, and investigating what drives SHBG upward, we can develop effective strategies to restore optimal hormonal function.