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Sex Hormone Binding Globulin: What Every Woman Should Know About SHBG

Learn how this often overlooked biomarker regulates the delicate balance of sex hormones like estrogen and testosterone.

Kalyn Weber
By Kalyn Weber
Korana Braun | Content Editor | InsideTracker
Edited by Korana Braun

Updated June 20, 2024.

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Sex hormone-binding globulin, or SHBG, is a powerful yet often overlooked biomarker that holds crucial insights into a woman's overall health and well-being. Since SHBG is related to testosterone and other sex hormones, many women remain unaware of their SHBG status and the significant role it plays in regulating sex hormones.

» Stay informed and proactive about your health by measuring SHBG levels

SHBG typically isn't included in standard bloodwork, leaving many women in the dark about this important marker. However, InsideTracker recognizes the value of SHBG testing and includes it in the Ultimate plan

What is Sex hormone-binding globulin (SHBG)?

SHBG is a glycoprotein, a molecule that consists of a carbohydrate plus a protein and is produced mainly in your liver. It binds to three sex hormones found in both men and women:

Its job is to transport these hormones throughout the blood to other tissues in the body. SHBG has a stronger affinity for DHT and testosterone (which are androgens) than estrogen. Therefore, it plays a significant role in maintaining the balance between estrogen and testosterone in a woman’s body.

» Find out if your SHBG levels are within the optimal range

The importance of optimal SHBG levels for women

Testosterone and other hormones play an important role in a woman’s overall physical and emotional health.  As a woman, you may have experienced times in your life when you knew your hormones were out of whack. SHBG makes sure that these hormones are transported throughout your body and are available for the tissues that need them.

Optimal SHBG levels decrease a woman’s risk of developing polycystic ovarian syndrome (PCOS), insulin resistance, and type 2 diabetes.

» Protect your future health by understanding your SHBG levels now

a bar chart showing average levels in female insider users

What are normal SHBG levels?

The optimal level of SHBG in the blood can vary depending on the source, but some say it's between 24.6–122 nanomoles per liter (nmol/L).

Optimal SHBG levels
Females (nonpregnant):18–144 nmol/L
Females over 50:50: 14–136 nmol/L

SHBG levels can also change based on several factors:

  • Age: Men's SHBG levels usually increase as they age, and testosterone levels decrease, while in women, data are scant.
  • Pregnancy typically raises SHBG levels, which usually return to normal after childbirth.
  • Puberty: SHBG levels rise during puberty, and high levels in children can prevent sex hormones from affecting body tissues. Low SHBG levels in children may cause early puberty.

» Take control of your health with complete SHBG testing and personalized science-backed recommendations

What causes low SHBG levels in women?

Women with low levels of Sex hormone-binding globulin are more likely to have higher testosterone levels, which can lead to androgenization, i.e., the development of masculine characteristics.

  • SHBG levels decrease as a result of taking certain hormones, such as androgens (i.e., testosterone), anabolic steroids, and norethisterone-related synthetic progesterone.
  • Certain conditions, like hypothyroidism, obesity, Cushing’s syndrome, and acromegaly (a condition where your body produces too much growth hormone), can also cause low SHBG levels.
  • Interestingly, insulin resistance, even without obesity, results in lower SHBG levels. 
  • Low SHBG is often associated with polycystic ovarian syndrome (PCOS).
  • Other signs of low SHBG in women include male-patterned hair growth or hair loss, menstrual irregularities, decreased breast tissue, and skin abnormalities.
  • Women with low SHBG are also at higher risk for developing cardiovascular disease, type 2 diabetes, and metabolic syndrome.

A chart representing the effects on SHBG.

What causes high SHBG levels in women?

Compared to men, women naturally have higher levels of SHBG. Women with high levels of SHBG have less available testosterone in their bodies. That’s bad news since testosterone plays an important role in maintaining energy levels, muscle development, bone health, and sex drive. Here's what causes high SHBG levels in women:

  • The aging process, particularly for women, increases SHBG levels, which means younger women tend to have lower SHBG levels than postmenopausal women.
  • Pregnancy increases SHBG even further, as SHBG is actually produced in the placenta tissue.
  • Some evidence suggests that continuous use of oral contraceptives can also increase your SHBG levels.
  • Finally, undernourishment, as seen in anorexia nervosa, and estrogen or thyroid hormone treatment can cause higher than normal SHBG levels in women.

» Address high SHBG levels to maintain balanced testosterone levels

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What’s next?

SHBG is an important biomarker, but it’s just one piece of the puzzle in the roadmap to optimal health for women.

InsideTracker can help provide you with a more complete picture by analyzing your levels of 48 blood biomarkers related to optimal wellness, including estradiol, progesterone, DHEAS, and thyroid-stimulating hormone.

» Discover 48 blood biomarkers InsideTracker measures