How does high SHBG affect my hormones?
High SHBG binds to sex hormones like testosterone and estrogen, reducing their free, active forms in your body. This can lead to symptoms like low libido, fatigue, and mood changes despite normal total hormone levels.
What is SHBG and why does it matter?
Sex hormone-binding globulin (SHBG) is a protein produced primarily by your liver that acts like a hormonal traffic controller in your bloodstream. Think of SHBG as a molecular taxi service that picks up sex hormones like testosterone and estrogen, carrying them through your blood to various tissues throughout your body.
While this transport function is essential, there's a catch: when hormones are bound to SHBG, they become biologically inactive. Only the free, unbound hormones can enter cells and trigger the effects we associate with these hormones, such as maintaining muscle mass, regulating mood, and supporting sexual function. This is why understanding your SHBG levels is crucial for assessing your true hormonal status.
The binding game: How SHBG works
SHBG has a particular affinity for certain hormones. It binds most strongly to dihydrotestosterone (DHT), followed by testosterone, and then estradiol (a form of estrogen). When SHBG levels are high, more of these hormones get bound up and become unavailable for use by your tissues. This creates a situation where your total hormone levels might appear normal on a blood test, but you could still experience symptoms of hormone deficiency because the free, active levels are low.
Common Symptoms by SHBG Level
| SHBG Level | Physical Symptoms | Sexual Symptoms | Mental Symptoms | |
|---|---|---|---|---|
| Low SHBG | Low SHBG (<20 nmol/L) | Acne, oily skin, hair loss, insulin resistance | May have normal libido but other metabolic issues | Mood swings, aggression |
| Normal SHBG | Normal SHBG (20-60 M, 20-120 F) | Generally balanced | Normal sexual function | Stable mood and cognition |
| High SHBG | High SHBG (>60 M, >120 F) | Muscle loss, increased fat, fatigue | Low libido, ED (men), vaginal dryness (women) | Depression, brain fog, anxiety |
Symptoms vary by individual and should be evaluated alongside free hormone levels.
How high SHBG affects different hormones
Impact on testosterone
High SHBG levels can significantly impact testosterone availability in both men and women. In men, elevated SHBG often leads to symptoms of low testosterone even when total testosterone levels appear normal. This happens because SHBG binds to testosterone with high affinity, reducing the amount of free testosterone available to tissues. Men with high SHBG may experience decreased libido, erectile dysfunction, reduced muscle mass, increased body fat, fatigue, and mood changes.
For women, the impact is equally important but often overlooked. Women need optimal levels of free testosterone for maintaining muscle tone, bone density, energy levels, and sexual desire. High SHBG can bind up the already lower levels of testosterone in women, leading to symptoms like low libido, difficulty building muscle, fatigue, and mood instability. Understanding your SHBG levels alongside your testosterone can provide crucial insights into your hormonal health.
Effects on estrogen
SHBG also binds to estrogen, though with slightly less affinity than testosterone. In women, high SHBG can reduce the amount of free estradiol available, potentially leading to symptoms similar to estrogen deficiency. These may include hot flashes, vaginal dryness, mood swings, and irregular menstrual cycles. The relationship becomes particularly complex during different life stages, such as pregnancy (when SHBG naturally rises) or menopause (when both estrogen and SHBG levels fluctuate).
In men, the SHBG-estrogen relationship is also important. While men have lower estrogen levels than women, this hormone still plays crucial roles in bone health, cardiovascular function, and even sexual function. High SHBG can reduce free estrogen to suboptimal levels, potentially affecting these systems.
Other hormonal interactions
While SHBG primarily binds sex hormones, its levels can be influenced by and interact with other hormones in your body. Thyroid hormones, for instance, can increase SHBG production. This is why people with hyperthyroidism often have elevated SHBG levels. Conversely, growth hormone and insulin-like growth factor 1 (IGF-1) tend to decrease SHBG production. Understanding these interactions is crucial for a comprehensive view of your hormonal health.
Common symptoms of high SHBG
The symptoms of high SHBG often mirror those of sex hormone deficiency, which can make diagnosis challenging without proper testing. Here are the most common symptoms experienced by people with elevated SHBG levels.
Physical symptoms
- Decreased muscle mass and strength
- Increased body fat, especially around the midsection
- Reduced bone density
- Hair thinning or loss
- Dry skin
- Joint pain and stiffness
- Decreased exercise performance and recovery
Sexual and reproductive symptoms
- Low libido or decreased sexual desire
- Erectile dysfunction in men
- Vaginal dryness in women
- Irregular menstrual cycles
- Fertility issues
- Decreased sexual satisfaction
Mental and emotional symptoms
- Depression or low mood
- Anxiety
- Irritability
- Brain fog or difficulty concentrating
- Memory problems
- Decreased motivation
- Sleep disturbances
What causes high SHBG levels?
Understanding what drives SHBG production can help you identify potential causes of elevation and guide treatment strategies. SHBG levels are influenced by various factors, from genetics to lifestyle choices.
Hormonal and metabolic factors
Several hormonal conditions can increase SHBG production. Hyperthyroidism (overactive thyroid) is one of the most common causes, as thyroid hormones directly stimulate SHBG synthesis in the liver. Conversely, hypothyroidism typically leads to lower SHBG levels. Estrogen also increases SHBG production, which is why women taking oral contraceptives or hormone replacement therapy often have elevated levels. Pregnancy naturally increases SHBG due to rising estrogen levels.
On the metabolic side, insulin resistance and diabetes tend to lower SHBG, while conditions that improve insulin sensitivity can raise it. This creates an interesting paradox where improving metabolic health might temporarily increase SHBG levels, potentially reducing free hormone availability.
Lifestyle and dietary influences
Your lifestyle choices significantly impact SHBG levels. Caloric restriction and low body weight tend to increase SHBG, which is why people with eating disorders or those on very low-calorie diets often have elevated levels. Excessive alcohol consumption can also raise SHBG by affecting liver function. Certain dietary patterns, particularly those very low in fat or protein, may contribute to higher SHBG levels.
Exercise generally helps optimize SHBG levels, but extreme endurance training can sometimes lead to elevations, particularly in athletes with low body fat percentages. This is part of the body's adaptive response to intense physical stress.
Medical conditions and medications
- Liver disease (SHBG is produced in the liver)
- HIV/AIDS
- Certain genetic variations affecting SHBG production
- Oral contraceptives and hormone replacement therapy
- Some anti-seizure medications
- Certain antidepressants
Testing and diagnosis
Proper testing is crucial for understanding how SHBG affects your hormonal health. A comprehensive hormone panel should include not just total hormone levels but also SHBG and calculated free hormone levels. This complete picture allows for accurate assessment of your hormonal status.
Key tests to consider
When evaluating SHBG and its impact on your hormones, several tests provide valuable information. For men, a complete panel should include total testosterone, SHBG, albumin (needed for free testosterone calculation), and calculated free testosterone. Additional tests might include estradiol, LH, FSH, and DHEA-S for a comprehensive view. Regular monitoring helps track changes and treatment effectiveness.
Women benefit from similar testing, though the interpretation differs based on menstrual cycle timing and life stage. Key tests include total testosterone, SHBG, estradiol, LH, FSH, and DHEA-S. For women experiencing symptoms, testing during the follicular phase (days 3-5 of the menstrual cycle) often provides the most consistent results.
Understanding your results
SHBG reference ranges vary by lab and can differ between men and women. Generally, levels between 20-60 nmol/L for men and 20-120 nmol/L for women are considered normal, though optimal levels may be narrower. More important than the SHBG number alone is how it relates to your total hormone levels and calculated free hormones. A high SHBG with normal total testosterone, for instance, often means low free testosterone and potential symptoms.
Natural ways to optimize SHBG levels
If your SHBG levels are elevated and causing symptoms, several natural approaches can help bring them into a more optimal range. These strategies focus on addressing underlying causes and supporting overall hormonal balance.
Dietary strategies
Your diet plays a crucial role in SHBG regulation. Ensuring adequate protein intake (0.8-1.2 grams per kilogram of body weight) can help moderate SHBG levels. Healthy fats, particularly omega-3 fatty acids and monounsaturated fats, support hormone production and may help optimize SHBG. Avoiding extreme caloric restriction is important, as very low-calorie diets tend to increase SHBG.
Some specific foods and nutrients may help lower SHBG. Vitamin D supplementation has been shown to reduce SHBG in some studies, particularly in those who are deficient. Magnesium and zinc also play roles in hormone metabolism and may help optimize SHBG levels. Cruciferous vegetables like broccoli and cauliflower contain compounds that support healthy estrogen metabolism, which can indirectly affect SHBG.
Lifestyle modifications
- Maintain a healthy body weight (both underweight and overweight can affect SHBG)
- Engage in regular strength training to support testosterone production
- Manage stress through meditation, yoga, or other relaxation techniques
- Ensure adequate sleep (7-9 hours per night)
- Limit alcohol consumption
- Avoid overtraining if you're an athlete
Targeted supplementation
Several supplements may help optimize SHBG levels, though individual responses vary. Boron supplementation (3-10mg daily) has been shown to reduce SHBG and increase free testosterone in some studies. Nettle root extract contains compounds that may bind to SHBG, potentially freeing up more testosterone. Tongkat ali (Eurycoma longifolia) has shown promise in reducing SHBG and improving free testosterone levels in several studies.
Always consult with a healthcare provider before starting any supplementation regimen, especially if you have underlying health conditions or take medications.
Medical treatment options
When natural approaches aren't sufficient to manage high SHBG and its symptoms, medical interventions may be necessary. Treatment typically focuses on addressing the underlying cause of elevated SHBG while managing symptoms.
Hormone replacement therapy
For men with high SHBG and low free testosterone, testosterone replacement therapy (TRT) may be appropriate. TRT can help overcome the binding effect of high SHBG by increasing total testosterone levels, thereby raising free testosterone even if SHBG remains elevated. Various forms of TRT are available, including injections, gels, patches, and pellets, each with different effects on SHBG levels.
Women with high SHBG and symptoms of androgen deficiency might benefit from testosterone therapy, though this requires careful monitoring and individualized dosing. Some women may also need estrogen optimization, particularly during perimenopause or menopause.
Addressing underlying conditions
Since high SHBG often results from other conditions, treating the root cause is essential. If hyperthyroidism is driving elevated SHBG, proper thyroid management will help normalize levels. For women on oral contraceptives experiencing high SHBG and related symptoms, switching to a non-oral form of birth control or an IUD may help, as these have less impact on SHBG production.
The importance of regular monitoring
Managing high SHBG and optimizing your hormonal health is rarely a one-time fix. Regular monitoring allows you to track progress, adjust treatments, and catch changes early. Most experts recommend testing every 3-6 months when actively addressing SHBG issues, then annually once levels stabilize.
Comprehensive testing should include not just SHBG and sex hormones but also related markers like thyroid function, metabolic health indicators, and nutritional status. This holistic approach ensures you're addressing all factors that might influence your SHBG levels and overall hormonal balance. Working with a healthcare provider experienced in hormone optimization can help you develop an effective, personalized strategy for managing high SHBG and achieving optimal hormonal health.
References
- Rosner W, Auchus RJ, Azziz R, Sluss PM, Raff H. Position statement: Utility, limitations, and pitfalls in measuring testosterone: an Endocrine Society position statement. J Clin Endocrinol Metab. 2007;92(2):405-413.[PubMed][DOI]
- Hammond GL. Plasma steroid-binding proteins: primary gatekeepers of steroid hormone action. J Endocrinol. 2016;230(1):R13-R25.[PubMed][DOI]
- Selby C. Sex hormone binding globulin: origin, function and clinical significance. Ann Clin Biochem. 1990;27(Pt 6):532-541.[PubMed][DOI]
- Narinx N, David K, Walravens J, et al. Role of sex hormone-binding globulin in the free hormone hypothesis and the relevance of free testosterone in androgen physiology. Cell Mol Life Sci. 2022;79(11):543.[PubMed][DOI]
- Maggio M, Snyder PJ, Ceda GP, et al. Is the haematopoietic effect of testosterone mediated by erythropoietin? The results of a clinical trial in older men. Andrology. 2013;1(1):24-28.[PubMed][DOI]
- Naghii MR, Mofid M, Asgari AR, Hedayati M, Daneshpour MS. Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines. J Trace Elem Med Biol. 2011;25(1):54-58.[PubMed][DOI]
Was this article helpful?
Frequently Asked Questions
How can I test my SHBG at home?
You can test your SHBG at home with SiPhox Health's Hormone Focus Program, which includes SHBG testing along with other key hormone biomarkers. For a focused assessment, the Men's Essential Hormone Panel also includes SHBG testing with free testosterone calculations.
What is the optimal SHBG range?
While normal ranges are 20-60 nmol/L for men and 20-120 nmol/L for women, optimal levels are often in the lower half of these ranges. The ideal SHBG level depends on your total hormone levels and symptoms rather than the number alone.
Can high SHBG cause erectile dysfunction?
Yes, high SHBG can contribute to erectile dysfunction by reducing free testosterone levels. Even with normal total testosterone, elevated SHBG can bind too much testosterone, leaving insufficient free hormone for normal sexual function.
How quickly can SHBG levels change?
SHBG levels change relatively slowly compared to hormones like testosterone. Significant changes typically take 4-12 weeks to occur, which is why consistent lifestyle modifications and patience are important when trying to optimize levels.
Does exercise affect SHBG levels?
Moderate exercise, especially strength training, can help optimize SHBG levels. However, extreme endurance training or overtraining can actually increase SHBG, particularly in athletes with very low body fat percentages.
This article is licensed under CC BY 4.0. You are free to share and adapt this material with attribution.
