By Zoom Heaton RPh.
Clinical Liaison – Women’s Health
Revelation Pharma

Sex hormone-binding globulin (SHBG) is a glycoprotein that plays a crucial role in the regulation of sex hormones, particularly testosterone, in the body. However, SHBG may also impact thyroid hormone metabolism and function. Understanding the intricate relationship between SHBG and hormones, including thyroid hormones, is essential for comprehensive hormone management and optimizing overall health.

The Role of SHBG in Hormone Management

Related resources

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SHBG acts as a carrier protein for sex hormones, including testosterone and estrogen, in the bloodstream. It binds to these hormones, limiting their bioavailability and regulating their distribution and clearance in the body. By binding tightly to sex hormones, SHBG helps maintain hormonal balance and prevent hormonal fluctuations that could lead to adverse health outcomes.

In addition to its role in sex hormone regulation, recent studies indicate that SHBG may interact with thyroid hormones, such as triiodothyronine (T3) and thyroxine (T4), influencing their metabolism and availability in the body. While the exact mechanisms underlying this interaction are still being elucidated, it is increasingly recognized that SHBG may play a role in thyroid hormone transport and utilization.

Implications of SHBG on Thyroid Function

  1. Thyroid Hormone Binding: Research suggests that SHBG may bind to thyroid hormones in the circulation, similar to its interaction with sex hormones. This binding may affect the distribution and delivery of thyroid hormones to target tissues, potentially influencing thyroid function and metabolism.
  1. Thyroid Hormone Transport: SHBG may serve as a carrier protein for thyroid hormones, aiding in their transport through the bloodstream and enhancing their stability and half-life. This process could impact the availability of thyroid hormones for cellular uptake and utilization.
  1. Hormonal Crosstalk: The interplay between SHBG, sex hormones, and thyroid hormones highlights the complex network of hormonal signaling and regulation in the body. Imbalances in SHBG levels or function could potentially disrupt this delicate equilibrium, leading to hormonal dysregulation and associated health concerns.

Clinical Considerations and Future Directions

  1. Hormone Testing: When evaluating hormone profiles, including sex hormones and thyroid hormones, healthcare providers may consider assessing SHBG levels to gain a more comprehensive understanding of hormonal status and interactions. Monitoring SHBG alongside other hormonal markers could inform diagnostic and treatment decisions.
  1. Hormone Replacement Therapy: In conditions where hormone replacement therapy is indicated, such as hypothyroidism or hormone imbalances, considering the impact of SHBG on hormone metabolism and delivery is essential for optimizing treatment outcomes. Tailoring therapy based on individual hormonal profiles, including SHBG levels, may improve therapeutic efficacy.

In conclusion, SHBG, traditionally known for its role in sex hormone regulation, may also have implications for thyroid hormone management and function. By recognizing the multifaceted roles of SHBG in hormonal balance and metabolism, healthcare providers can enhance their approach to hormone-related disorders and optimize patient care.


  1. Haring R, Baumeister SE, Volzke H, et al. Prospective inverse associations of sex hormone binding globulin and molar ratios with hypothyroidism risk: the Study of Health in Pomerania. Thyroid. 2011;21(5):501-509. doi:10.1089/thy.2010.0340.
  2. Laurent MR, Hammond GL, Blokland M, et al. SHBG: hormone, target for therapy or just a marker? Horm Metab Res. 2016;48(7):415-425. doi:10.1055/s-0042-105570.
  3. Bhasin S, Brito JP, Cunningham GR, et al. Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2018;103(5):1715-1744. doi:10.1210/jc.2018-00229.