Sex hormone binding globulin is a carrier protein produced by the liver that plays a critical role in regulating the amount of the unbound steroids, testosterone, dihydrotestosterone (DHT) and estrogen in the blood. Unbound Hormone is the amount of hormone that is available to be used by the body and not tied up in a protein globulin. The unbound portion is called “free testosterone”, for instance, and it is the fraction that actually relieves symptoms and provides the health and quality of life benefits.
Hormones which are bound up are not available for use, which is why testing free testosterone and SHBG, gives us the information needed. Unfortunately, conventional medicine ignores SHBG, and just relies on total testosterone. It’s the free testosterone that can affect one’s symptoms.
SHBG has a stronger affinity for DHT and testosterone, as compared to estrogen's, making it significant in the role of maintaining the delicate balance between estrogen and testosterone in a woman’s body. There are times in their life when it just feels like their hormones are just out of whack. SHBG controls the transportation of hormones throughout the body, to make them available when needed. Optimal levels decrease a woman’s risk of developing polycystic ovarian syndrome, and type 2 diabetes.
An increase of the SHBG due to cortisol (which increases with stress), can increase your body fat, decrease your ability to lose weight, affect insulin function, and decrease the effectiveness of your hormones. It’s important to know how stress, anxiety and even depression are affecting your body’s health, and how much cash (free testosterone) you have to spend.
Causes of high SHBG levels in women
The aging process - Pregnancy - Estrogen or thyroid hormone replacement - Hyperthyroidism
Compromised liver function / Cirrhosis of the liver - Birth control pills - Extreme weight loss as in anorexia nervosa - Cigarette smoking - Certain medications - Fibrocystic breast disease - elevated cortisol levels from stress
Causes of low SHBG in women
PCOS (polycystic ovarian syndrome) – Hypothyroidism - Diabetes/insulin resistance
Causes of high SHBG in men
Elevated estradiol levels from conversion of testosterone – Hyperthyroidism – Aging - Extreme weight loss in anorexia nervosa - Compromised liver function - Cigarette smoking - Testicular cancer
Causes of low SHBG in men
Hypothyroidism - Diabetes/insulin resistance
SHBG is an important bio-marker… but it’s just one piece of the puzzle in the road-map to optimal health for men and women.