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SHBG (Sex Hormone-Binding Globulin) is a protein that binds sex hormones. It is produced in the liver and binds the majority of testosterone and 5-dihydrotestosterone (DHT), as well as a small amount of estradiol.

  • Bound hormones are inactive and do not participate in metabolism.
  • Only 1–2% of total testosterone is in its free (bioavailable) form.
  • Changes in SHBG levels alter the ratio between bound and free hormones.
  • SHBG testing is used to correctly interpret testosterone and estradiol test results.
  • The analysis is performed on a blood sample drawn from a vein.
  • The test should be taken after 8–14 hours of fasting.
  • Before the test, avoid:
    • Physical and emotional stress
    • Alcohol consumption
  • For women, the appropriate menstrual cycle day for testing should be determined by the doctor.

SHBG testing is relevant for both men and women in cases of:

  • Alopecia (hair loss)
  • Acne (skin rash)
  • Oily seborrhea

Indications for Women:

  • Hirsutism (excessive hair growth)
  • Anovulation (lack of ovulation)
  • Amenorrhea (absence of menstruation for more than 3 months in reproductive-age women)
  • Polycystic ovary syndrome (PCOS)

Indications for Men:

  • Chronic prostatitis
  • Erectile dysfunction
  • Decreased libido (sexual drive)

Causes of Increased SHBG Levels

  • Hyperestrogenism (excess estrogen)
  • Hyperthyroidism
  • Hepatitis
  • HIV infection
  • Use of certain medications, such as:
    • Oral contraceptives
    • Phenytoin
       

      Causes of Decreased SHBG Levels

    • Nephrotic syndrome
    • Major collagen diseases
    • Hyperandrogenism (excess androgens)
    • Insulin resistance
    • Hypothyroidism
    • Acromegaly
    • Cushing’s disease
    • Hyperprolactinemia
    • Polycystic ovary syndrome (PCOS)
    • Liver cirrhosis

    • Medications That Decrease SHBG Levels:

    • Danazol
    • Androgens
    • Glucocorticoids
    • Somatostatin analogs