Heal Yourself At Home

Sex Hormone-Binding Carrier Proteins

Sex Hormone Binding Globulin (SHBG)

Corticosteroid Binding Globulin (CBG)

SHBG (sex hormone binding globulin)

Aka. TeBG (TESTOSTERONE-estrogen Binding Globulin)

SHBG binds to estrogen and TESTOSTERONE in the blood(making them less bioavailable)

–   Bioavailability of ESTRADIOL or TESTOSTERONE is determined by the level of SHBG - ESTRADIOL and TESTOSTERONE travel in the blood either strongly (but reversibly) bound to SHBG (ESTRADIOL 40%) or loosely bound to serum albumin (ESTRADIOL 59%).E.g. Only about 1-2% of circulating ESTRADIOL is “free”to enter a cell and activate its receptor.

SBGH level is delicately balanced by enhancing and inhibiting factors:

–    SHBG is
increased by:
(makes otherwise unbound hormones LESS bioavailable)

Liver disease, alcohol

Hyperthyroidism - high levels of thyroxine (T3)


High levels of estrogen - E.g. use of HRT, oral contraceptives (metabolized by liver);

High levels of GROWTH HORMONE

–    SHBG is reduced by: (makes otherwise bound hormones MORE bioavailable)

Higher circulating INSULIN levels – (note however, that recent evidence reveals that liver's fat production reduces SHBG, and not any direct effect of INSULIN);

Obesity - obesity leads to high insulin levels, which causes a reduction in the liver's productionand circulating levels of SHBG (see note above); note that obesity also increases estrogen production in adipose cells via the aromatase enzyme; Thus, obesity can promote cancers such as breast and endometrial cancer –as estrogen becomes more bioavailable (free/unbound to SHBG) for its target tissues.



Corticosteroid-binding globulin (CBG)


Cushing's disease;

Soy - up to 10% reduction;

Nettle root - contains compounds that bind to SHBG; nettle root is also anti-aromatase and therefore acts against estrogen production.

High/Low SHBG Conditions

–   Low SHBG (making hormones MORE bioavailable) - seen in polycystic ovary syndrome, diabetes, hypothyroidism.

–   High SHBG (making hormones LESS bioavailable) - seen in pregnancy, hyperthyroidism, anorexia nervosa. Recent research links high SHBG levels with breast and testicular cancer.

SHBG production sites

–   SHBG is produced mainly in the liver cells and released into the bloodstream - other production sites are the brain, uterus, placenta and testes (where it is sometimes called androgen-binding protein).

CBG (Corticosteroid-binding Globulin)

CBG (a.k.a. transcortin) binds to PROGESTERONE, CORTISOL (and other corticosteroids) in the blood

–   Bioavailability of PROGESTERONE, CORTISOL (and other corticosteroids) is determined by level of CBG

–   PROGESTERONE is bound by CBG (~18%), albumin (~80%), SHBG (0.6%) and ~2% exists in the free state

Clinical Reproductive medicine and surgery, 2007

CBG level is balanced by enhancing and inhibiting factors:

–    CBG is
increased by:
(makes otherwise unbound hormones LESS bioavailable)

Estrogens / Pregnancy

–    CBG is reduced by: (makes otherwise bound hormones MORE bioavailable)



CBG production

–   CBG is produced by the liver

Hormones Links

HORMONES- Related Links:


Hormones 101 –“Feel Good, Look Good”

Chart of Human Hormones

Testing Hormone Levels

> Take Hormone Test

Synthetic Hormones

–“Frankenstein Version of Natural Hormones”

Balance Adrenal "Stress Managment" Glands


5-HTP –“SSRI Alternative”

SEROTONIN –“Mood Hormone”

MELATONIN –“Darkness Hormone”

> The Biological Clock

T3 and T4 - “Thyroid Hormones (Triiodothyronine and Thyroxine)”

HISTAMINE –“Inflammatory Response Hormone”

Fight or Flight Catecholamines:


DOPAMINE –“Go Get it! /Reward Hormone”


Low Dose Naltrexone (LDN)- “For auto immune disease, cancer, AIDS, COPD and the common cold”

FSH, LH and GnRH

PROLACTIN –“Cool Down Hormone”

INSULIN –“Blood Sugar Uptake”, GLUCAGON, IGF

LEPTIN –“Curb appetite / Burn Fat”

GHRELIN –“Hunger Hormone”


Steroid Hormones

Steroid enzymes affecting Steroid Production /Activity


CORTISOL –“Stress Hormone”



Sex Steroid Hormones

Sex Steroid Hormones

Sex hormone-binding carriers

Estrogens –“Predominantly Female Sex Hormones”



PROGESTERONE –“Precursor to Androgens, Estrogens and Corticoids”

Estrogens and PROGESTERONE in Lifestage Events

Androgens -"Predominately Males Sex Hormone"


Vitamin D - The Sunshine Vitamin

CALCITRIOL (active form)

CALCIDIOL (circulating form)