Sex Hormone-binding Globulin (SHBG)

What is the Sex Hormone-binding Globulin?

The sex hormone binding globulin is a protein that is made by the liver. One of its most important roles is bonding to some hormones, namely testosterone, DHT and an estrogen called estradiol. In their bound state, SHBG transports the three hormones into the blood making them biologically inactive (since they are no longer freely roaming). When you test SHBG levels, you are evaluating whether there is a deficiency or excess of these hormones, especially testosterone. So, when your SHBG levels are high, you are less free hormones that your body can use for its functions; and, when your SHBG levels are low, more hormones are roaming in their unbound form, ready to assist your body when needed.

Women have higher levels of SHBG-bound testosterone than men. For them, this binding protein helps regulate the levels of androgens and estrogens that are available and circulating throughout the body. You need to know that SHBG is more likely to bind to testosterone than the other hormones. So, for women who have low levels of this protein, signs and symptoms of high androgen levels will appear. These include: having a deep voice, acne, having excess hair on the face and body, high muscle mass, having irregular periods, and a clitoris that is much larger than it should be.

Why take the Sex Hormone-binding Globulin test?

This test is a great  tool to evaluate why testosterone levels are low in men. Also, this test is used to evaluate the signs and symptoms of androgens in women.

If you have signs of low SHBG levels, you need to get tested. Men usually experience symptoms such as having fluid retention, acne, high appetite, weight gain, high muscle mass and mood swings. These signs are the result of ending up with high levels of free testosterone. If high levels of estrogen are the result of your low SHBG levels, men will show signs of enlarged breast tissue and erectile dysfunction.

Women who show signs of low SHBG levels need to be tested as well for this hormone. Such signs include weigh gain, excess body and facial hair, acne, mood changes, menstrual changes, irregular periods, bloating and breast tenderness. These signs are caused by the upsurge of hormones, testosterone and estrogen, that accompanied low SHBG levels.

People who are at high risk for having low SHBG levels need to be tested. this includes those who are obese, have insulin resistance, hypothyroidism, Cushing syndrome, non-alcoholic fatty liver disease and the use of androgen steroids.

For men, this hormone test is a great indicator for the cause of infertility, low sex drive and ED. For women, this SHBG test can help identify the cause behind irregular menstrual periods, infertility, acne and excess facial and body hair.

What causes the levels of Sex Hormone-binding Globulin to rise?

You do not need to prepare yourself for this test. Some medications can alter your real results. These include opiates, medications that control the central nervous system, vitamins, as well as herbs and dietary supplements. If you exercise rigorously on a daily basis, or you have an eating disorder, your levels will be sabotaged.

What your Sex Hormone-binding Globulin test results of mean?

The normal levels of this hormone are different for men and women. In adults, men should have their levels between 10 and 57 nanomoles per liter. Women, who are not pregnant, need to have values between 18 and 144 nanomoles per liter. Values can vary from a lab to another.

Men have lower SHBG levels than women; however, his levels will increase with age as a result of a decrease in testosterone levels. Women who are pregnant have high levels of this hormone; but, once the baby is born, levels will return to their pre-pregnancy levels. Also, in both genders, SHBG levels are higher during puberty and start decreasing afterwards.

When the SHBG levels are high, this normally insinuate that you have less free testosterone than is needed by your body. Low levels of SHBG can mean that you have high levels of testosterone that is bioavailable.

If your SHBG levels are high, you may have liver disease, hyperthyroidism, eating disorders like anorexia nervosa, corticosteroids, low sex hormone production, and pregnancy. High levels are also seen in people who are on hormone replacement therapy.

Low levels of SHBG are seen in people who are obese, have polycystic ovary syndrome, have hypothyroidism, have Cushing disease, or due to androgen use like steroids. Many treatments exist that can improve low levels of SHBG. These consist of getting regular exercise, drinking coffee, taking some oral contraceptives, increasing your dietary intake of fiber while lowering sugar in your diet, losing weight and taking some herbal and dietary supplements.

A study published by the Journal of Clinical Endocrinology and Metabolism, explained that levels of SHBG are indirectly proportional to weight. After examining a total of 1522 men who are between the ages of 40 and 70, it was found that the daily intake of fat, calories and carbohydrates was not affecting the levels of SHBG. On the other hand, fiber and protein intake does alter the binding protein’s levels: high fiber and protein diets led to an increase in bioavailable testosterone level, which means that SHBG levels were decreased. More studies are needed to explore the link further.

Where can I get a Sex Hormone-binding Globulin test near me?

Please use our Lab Locator to find find a convenient testing location.

Reviewed By: Dr. Kurt Kloss, MD
Last Reviewed Date: Aug 03, 2022