Sex Hormone-Binding Globulin or SHBG is produced mainly by the liver. However, the brain, ovaries, uterus, breast, and placenta also contribute in minor amounts.
Its function is to bind to your sex hormones, such as estradiol and testosterone, and transport them throughout your body. Sometimes SHBG levels fluctuate.
Measuring SHBG concentrations may help diagnose thyrotoxicosis, puberty problems, and infertility, and for keeping track of anti-androgen and sex-steroid therapy.
Since SHBG and other sex hormones are connected, many people are unaware of their SHBG levels. But people should pay close attention to the biomarker SHBG.
In this article, we will be looking at all about SHBG.
What Is SHBG?
The liver produces a protein known as SHBG (sex hormone binding globulin), which strongly binds to the steroids DHT, estradiol, and testosterone and carries them inactively[1] in the blood.
Especially when androgen levels are within normal ranges and this does not match the clinical picture, SHBG levels are recommended in the evaluation of hirsutism in women as well as for erectile dysfunction, decreased libido, and infertility in men.
Pregnancy[2], anorexia, growth hormone deficiency, aging, hyperthyroidism[3], androgen deficiency, hyperprolactinemia, liver disease, estrogen, and active porphyria may all lead to increased SHBG levels.
Hyperinsulinemia, obesity[4], hypothyroidism, glucocorticoids, excess growth hormone, progestin, and androgens are all associated with decreased SHBG levels.
What Does SHBG Do?
Certain sex hormones are transported to various parts of the body through binding with SHBG.
The amount of SHBG hormones in your blood determines the percentage of sex hormones that are circulating in the bound state.
A higher percentage of sex hormones will bind to SHBG at higher doses, leaving a lower percentage biologically active and free.
A higher percentage of sex hormones circulate[5] in the free state when SHBG levels are low because fewer sex hormones are protein-bound.
Because they affect the percentage of sex hormones that are biologically active, abnormally low or high SHBG levels may be problematic.
The complex hormonal ecosystems that are in place in your body could be disturbed by such imbalances.
Symptoms Of Low SHBG
The amount of unbound and free testosterone may rise abnormally when your SHBG is low.
Low SHBG may therefore result in symptoms that are similar to those brought on by both an excess of testosterone and estrogen in the body, which could result in the development of “male” features.
Here are some of the symptoms of low SHBG in women:
- The excess hair growth
- Irregular or loss of periods
- Weight gain[6]
- Acne[7]
- Difficulty conceiving
- Hair loss[8]
- Increased risk of type two diabetes and high cholesterol
Here are some symptoms of low SHBG in men:
- Acne[9]
- Fluid retention
- Increased muscle mass
- Weight gain and increased appetite
- Mood swings
- Larger breast tissue
- Erectile dysfunction
Symptoms Of High SHBG
The quantity of estrogen and testosterone that the body may use is decreased by high SHBG.
As a result, the symptoms of high SHBG levels are the same as those brought on by low levels of estrogen and testosterone. Some of them are:
- Reduced bone and muscle mass
- Vaginal dryness[10]
- Anxiety and depression
- Decreased sex drive
What Is The Sex Hormone Binding Globulin Test?
The main and predominant male hormone is testosterone. Men and women both need it for a variety of bodily processes, and when levels are too low, it may result in several health problems.
Unfortunately, as many people are aware, testosterone levels gradually decrease as we age. Lower testosterone levels could be caused by a variety of environmental[11] sources.
Age or external factors aside, symptoms show up, issues develop, and solutions are required to halt the decline. The treatment for this issue for many men is TRT.
The Sex Hormone Binding Globulin test is one of those hormone tests to keep a check on. The results of this test will be used by your doctor to determine your blood’s SHBG protein levels.
It frequently occurs in conjunction with other tests that measure testosterone levels. The actual blood test is straightforward and should take only a few minutes.
When your doctor thinks your testosterone levels are off, they will typically prescribe these tests. That could indicate that you have too little testosterone if you’re a man.
Your levels may be too high for women. If you use any opioids, vitamins, or other recreational drugs, or if you suffer from an eating disorder, be sure to let your doctor know.
How Does SHBG Test Work?
The sex hormone binding globulin test may assist determine whether males have low testosterone levels and whether women produce too much testosterone.
It could be requested together with other tests to determine how well a person’s sex hormones are functioning.
-
Men
An adult male may have his total testosterone and SHBG levels checked to assist diagnose erectile dysfunction, diminished sex drive, and infertility.
In situations where total testosterone findings do not match the clinical indications, measuring[12] SHBG in addition to testosterone could be extremely useful.
The term total testosterone in the blood refers to the entire amount of testosterone present in the blood and does not differentiate between unbound and bound testosterone.
This is frequently sufficient to assess patients for potential insufficiency or excess in testosterone production.
The total testosterone, however, might not be a reliable indicator of the quantity of testosterone that is accessible to the body’s tissues if a person’s SHBG level is not normal.
-
Women
The adrenal glands and the ovaries in women produce very little testosterone.
The hormone balance may be upset by even little increases in testosterone production, leading to symptoms like excessive body and face hair, acne, infertility, and skipped or irregular[13] menstruation cycles.
The disorder known as PCOS (polycystic ovarian syndrome), which is characterized by excessive production of male sex hormones, frequently causes these and other signs and symptoms.
Testing for testosterone and SHBG may help identify and assess cases of PCOS, low SHBG levels, and excessive testosterone production in women.
Why Do People Need SHBG Test?
Your doctor may examine your total and free testosterone levels if you exhibit signs of high or low testosterone.
However, sometimes these testosterone levels do not give your doctor a full picture of what’s happening with your sex hormones.
The percentage of testosterone that is truly accessible to your cells and tissue could be determined by adding an SHBG test.
This is because it may further distinguish between the percentage of testosterone that is free testosterone, albumin-bound, and SHBG-bound.
These ratios could be particularly crucial if your total testosterone level appears to be within the usual range but you’re still experiencing symptoms of low testosterone.
Additionally, an abnormal SHBG level may occasionally point to a health issue.
Conclusion
Your bloodstream carries SHBG, which binds to and transports your sex hormones, including estrogen, dihydrotestosterone (DHT), and testosterone.
Consider SHBG as control over how much of these sex hormones your body may utilize. Only sex hormones that aren’t linked to SHBG could reach your cells.
Compared to only checking your testosterone levels, an SHBG test gives your doctor a more complete view of your sex hormone levels.
Discuss the best course of action with your doctor if your SHBG level is low or high.
References/Sources
Working4Health prefers using primary and verified references. We have strict sourcing guidelines and our primary references include peer-reviewed research, academic, and medical institution studies.
- C Selby. Sex hormone binding globulin: origin, function and clinical significance. Ann Clin Biochem. 1990 Nov;27 ( Pt 6):532-41. doi: 10.1177/000456329002700603. Available from: https://pubmed.ncbi.nlm.nih.gov/2080856/
- Monique M. Hedderson, Fei Xu, Jeanne A. Darbinian, et. al. Prepregnancy SHBG Concentrations and Risk for Subsequently Developing Gestational Diabetes Mellitus. Diabetes Care. 2014 May; 37(5): 1296–1303. Published online 2014 Apr 10. doi: 10.2337/dc13-1965
- David M Selva and Geoffrey L Hammond. Thyroid hormones act indirectly to increase sex hormone-binding globulin production by liver via hepatocyte nuclear factor-4alpha. J Mol Endocrinol. 2009 Jul;43(1):19-27. doi: 10.1677/JME-09-0025. Epub 2009 Mar 31. Available from: https://pubmed.ncbi.nlm.nih.gov/19336534/
- Lori A. Cooper, Stephanie T. Page, John K. Amory, et. al. The association of obesity with sex hormone-binding globulin is stronger than the association with ageing – implications for the interpretation of total testosterone measurements. Clin Endocrinol (Oxf). 2015 Dec; 83(6): 828–833. Published online 2015 May 11. doi: 10.1111/cen.12768.
- Geoffrey L. Hammond. Diverse Roles for Sex Hormone-Binding Globulin in Reproduction. Biol Reprod. 2011 Sep; 85(3): 431–441.Published online 2011 May 25. doi: 10.1095/biolreprod.111.092593.
- Julie E. Buring, JoAnn E. Manson, Melissa E. Weinberg, et. al. Low Sex-Hormone Binding Globulin is Associated with the Metabolic Syndrome in Postmenopausal Women. Metabolism. 2006 Nov; 55(11): 1473–1480. doi: 10.1016/j.metabol.2006.06.017
- D M Lawrence, M Katz, T W Robinson, et. al. Reduced sex hormone binding globulin and derived free testosterone levels in women with severe acne. Clin Endocrinol (Oxf). 1981 Jul;15(1):87-91. doi: 10.1111/j.1365-2265.1981.tb02752.x. Available from: https://pubmed.ncbi.nlm.nih.gov/6458423/
- J A Miller, C R Darley, K Karkavitsas, et. al. Low sex-hormone binding globulin levels in young women with diffuse hair loss. Br J Dermatol. 1982 Mar;106(3):331-6. doi: 10.1111/j.1365-2133.1982.tb01732.x. Available from: https://pubmed.ncbi.nlm.nih.gov/7199929/
- Robyn Smith, Neil Mann, Henna Mäkeläinen, et. al. A pilot study to determine the short-term effects of a low glycemic load diet on hormonal markers of acne: a nonrandomized, parallel, controlled feeding trial. Mol Nutr Food Res. 2008 Jun;52(6):718-26. doi: 10.1002/mnfr.200700307. Available from: https://pubmed.ncbi.nlm.nih.gov/18496812/
- L. Elaine Waetjen, Sybil L. Crawford, Po-Yin Chang, et. al. Factors associated with developing vaginal dryness symptoms in women transitioning through menopause: a longitudinal study. Menopause. 2018 Oct; 25(10): 1094–1104. doi: 10.1097/GME.0000000000001130
- SHBG Blood Test. Available from: https://medlineplus.gov/lab-tests/shbg-blood-test/
- Michaël R. Laurent, Geoffrey L. Hammond, Marco Blokland, et. al. Sex hormone-binding globulin regulation of androgen bioactivity in vivo: validation of the free hormone hypothesis. Sci Rep. 2016; 6: 35539. Published online 2016 Oct 17. doi: 10.1038/srep35539
- M. Maggio, F. Lauretani, S. Basaria, et. al. Sex hormone binding globulin levels across the adult lifespan in women – The role of body mass index and fasting insulin. J Endocrinol Invest. 2008 Jul; 31(7): 597–601. doi: 10.1007/BF03345608
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Otella has an experience of around eight years of writing about health and nutrition-related topics. She is a full-time mother and a housewife, and the time she has left after doing her mother and household duties is spent writing for Working for Health as a full-time writer. Her life goal is to raise both her boys into a gentleman, and at the same time, she wants to educate people on how to keep themselves fit by tweaking their daily diet.