Hormones · Blood

SHBG

The protein that binds testosterone and estradiol in the blood; needed to know how much testosterone is actually active.

At a glance

Measured in blood
In 11 test panels
Check the preparation

Explanation

SHBG: what is measured?

SHBG (sex hormone-binding globulin) is made in the liver and binds testosterone and estradiol, which makes them inactive. In men about half of the testosterone is bound to SHBG, in women about three quarters. The higher the SHBG, the less free testosterone remains at the same total value. The result is therefore almost always used together with total testosterone to calculate free testosterone.

What can it detect?

An abnormal amount of active testosterone in men in whom the total value is hard to interpret (overweight, older age, liver disease)
Too much active male hormone in women with PCOS, excess hair growth or an irregular cycle: SHBG is often low in these cases
A sign of insulin resistance or a thyroid disorder, which strongly affect SHBG

Result

What does the result mean?

SHBG too high

A raised SHBG means that less free testosterone is available than the total testosterone suggests. Common causes are the contraceptive pill and other estrogens, pregnancy, an overactive thyroid, liver disease, older age and underweight. In men with a raised SHBG, total testosterone can be normal while there is still a shortage of active hormone.

SHBG too low

A low SHBG means that more free testosterone is available than the total value shows. It is common with overweight, insulin resistance and type 2 diabetes, with an underactive thyroid, with use of anabolic steroids or testosterone, and in women with PCOS. In men with overweight, this is the reason that a low total testosterone often still comes with a normal free testosterone.

After an abnormal result

The GP uses SHBG to calculate free testosterone and assesses this together with the symptoms and total testosterone. With a markedly abnormal SHBG without a clear cause, thyroid or liver function is sometimes checked.

Reliability

How reliable is the test?

SHBG is not a disease marker on its own but a supporting value: it tells you how total testosterone should be read. The guidance of the Dutch Society for Endocrinology (NVE) advises measuring SHBG as well if total testosterone is in the borderline range or if there is a reason for an abnormal SHBG, such as overweight or liver disease. The measurement itself is stable and has little daily rhythm; interpretation always needs total testosterone as well.

What can affect the result?

Estrogens (the pill, hormone therapy), pregnancy and a thyroid disorder strongly raise or lower SHBG without anything being wrong with the sex hormones.
Overweight, insulin resistance, anabolic steroids and corticosteroids lower SHBG.
A stand-alone SHBG without total testosterone cannot be interpreted; the calculation of free testosterone differs between laboratories.

Preparation

Do you take biotin (vitamin B8, often in hair and nail supplements)? Stop at least 2 days before the sample is taken, or 4 days for a high dose.

Who it is for

Who is the test useful for?

Useful for

Useful together with total testosterone: in men with symptoms of testosterone deficiency, especially with overweight, liver disease or older age, and in women with excess hair growth, acne or an irregular cycle in whom PCOS is being considered. As a stand-alone test without testosterone, SHBG has no value; in healthy people without symptoms, measuring it is not needed.

How common is it?

SHBG abnormalities are not a disease in themselves. They occur mainly in common situations: overweight and type 2 diabetes (low SHBG), pill use and older age (high SHBG). Among women of childbearing age, about 5 to 10 in 100 have PCOS, in which SHBG is often low.

NHG guideline on amenorrhea and the NVE guidance on hypogonadism in adult men

Drawbacks and risks

An abnormal SHBG is sometimes seen as a problem in itself, while it is usually a result of pill use, weight or age and needs no treatment.

Get tested

SHBG: test panels

SHBG is part of these test panels. You order online and have your blood drawn at a collection point or collect the sample at home.

Blood draw
Sex Hormone-Binding Globulin (SHBG)
SHBG; binding of testosterone and estradiol.
€ 35,00
Blood draw
Bodybuilder Test
Panel for strength and muscle development; hormones, liver, and muscles.
€ 134,00
Blood draw
Free Testosterone
Available testosterone; calculated using total testosterone, SHBG, and albumin.
€ 71,00
Fingerstick
Sex Hormone-Binding Globulin (SHBG)
SHBG; binding of testosterone and estradiol.
€ 35,00
Blood draw
InsideTracker
InsideTracker Blood Analysis: analyze 48 biomarkers for complete health optimization and personalized recommendations.
€ 335,00
Blood draw
Hormones Male
Total testosterone, free testosterone, SHBG, creatinine, and eGFR. For men with hypogonadism, low libido, or during strength training.
€ 125,00
Blood draw
Hormone Recovery (After Steroids)
Testosterone, free testosterone, SHBG, LH, FSH, estradiol, TSH, liver function, and lipid profile. For recovery after anabolic steroid use.
€ 325,00
Blood draw
Endurance Sports
Complete blood count, iron status (ferritin, transferrin), kidney function, liver function, testosterone, and hs-CRP. For athletes and endurance sport participants.
€ 203,00
Blood draw
Supplemental: Testosterone Replacement Therapy (TRT)
Complete hormonal analysis with testosterone, DHEA-S, thyroid, blood count, liver function, kidney function, lipids, glucose, HbA1c, insulin, hs-CRP, vitamin D and ferritin.
€ 335,00

How reliable is the test?

SHBG