Sex Hormone-Binding Globulin (SHBG)

Overview

Sex hormone-binding globulin (SHBG) is a glycoprotein primarily produced in the liver that plays a crucial role in regulating the levels of sex hormones, such as testosterone and estradiol, in the bloodstream^[1]. SHBG binds these hormones, making them unavailable for immediate use by cells, thus controlling their bioavailability and activity^[3]. Tracking SHBG levels is important for diagnosing and managing conditions related to hormonal imbalances, such as hirsutism and hyperandrogenism^[4].

Scientific Background

SHBG is synthesized mainly in the liver and is influenced by various factors, including estrogen, thyroid hormones, and insulin^[1]. It has a high affinity for dihydrotestosterone (DHT), moderate affinity for testosterone, and lower affinity for estradiol^[3]. SHBG"s role is pivotal in maintaining hormonal balance and supporting reproductive health by regulating the distribution of sex hormones between bound and free states^[5].

Measurement and Testing

SHBG levels are typically measured using electrochemiluminescence immunoassay (ECLIA)^[4]. Factors such as age, gender, and certain medications can affect test results^[4]. Testing is recommended for individuals with symptoms of hormonal imbalances or when assessing the effectiveness of hormone therapies^[5].

Reference Ranges

Normal SHBG levels vary by gender and age. For men, typical ranges are between 10 and 57 nmol/L, while for non-pregnant women, they are between 18 and 144 nmol/L^[2]. Levels can be influenced by factors such as pregnancy, thyroid status, and obesity^[4].

High Values

Elevated SHBG levels are often seen in conditions like hyperthyroidism, cirrhosis, and pregnancy^[1]. High SHBG can lead to reduced bioavailability of sex hormones, potentially affecting fertility and libido^[4]. Symptoms may include decreased sexual desire or fertility issues^[5].

Low Values

Low SHBG levels are associated with conditions such as hirsutism, polycystic ovary syndrome (PCOS), and obesity^[2]. Reduced SHBG can result in increased levels of free testosterone and estradiol, leading to symptoms like acne, hirsutism, and irregular menstrual cycles^[2].

Improving Biomarker Levels

Lifestyle modifications, such as weight loss and improved insulin sensitivity, can help normalize SHBG levels^[5]. Certain medications, like oral contraceptives, can also influence SHBG levels^[4]. While supplements are not typically recommended for SHBG management, maintaining a balanced diet and healthy lifestyle is crucial^[5].

Importance of Tracking

Monitoring SHBG levels is essential for diagnosing hormonal imbalances and guiding treatment decisions^[5]. It helps in assessing the effectiveness of therapies aimed at regulating sex hormone levels and can provide insights into metabolic health^[4].

Disclaimer

The information provided in this document is for educational purposes only and does not constitute medical advice. It is essential to consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.