Human Chorionic Gonadotropin (hCG)

Take-home points

• hCG is a hormone that stimulates testosterone and sperm production in men.
• The presence of low hCG may be used to diagnose or explain the development of hypogonadism and low sperm counts.
• hCG therapy may stimulate the natural production of testosterone during TRT or the use of anabolic steroids, though this is a contentious discussion in the medical community.

‍What is hCG and what does it do?

Human chorionic gonadotropin, commonly known as hCG, is a hormone that is more often than not linked to women's health. Because hCG aids in producing progesterone, it is the hormone that pregnancy tests use to determine if a woman is pregnant.

However, men also produce small amounts of hCG to synthesise progesterone and stimulate leydig cells in the testicles to produce testosterone. For this reason, hCG is relevant to men's health conditions such as hypogonadism (low testosterone) and sexual dysfunction.

What are normal hCG levels in men?

There are no universal healthy ranges of hCG in men, though less than 20 IU/L is generally considered normal in adult men. The normal upper limit can double (up to 40 IU/L) in men over 70 years old, as the hCG level is thought to increase naturally with age.

What do high or low hCG levels indicate?

Because there is no universal healthy range of hCG in men, there is no clinically low hCG level. However, some studies suggest lower hCG levels are linked to low sperm production. In a 2011 study,¹ males with lower sperm counts and poor sperm quality had significantly lower levels of hCG. How much hCG is required to prevent these potential issues is unknown.

A low hCG level, alongside other hormone readings, could indicate a dysfunction of the pituitary gland, which is a gland that produces numerous hormones in the body. In particular, the diagnosis of secondary hypogonadism (a form of hypogonadism caused by abnormalities in the pituitary gland or hypothalamus) partly depends on a low hCG reading. If a low hCG reading is present from birth, it could be used to diagnose Kallmann’s syndrome or normosmic idiopathic hypogonadotropic hypogonadism.²

Conversely, high hCG levels are not considered a clinical health issue in men. Some research suggests that high hCG may signify certain medical conditions, such as certain types of cancer, but research is considerably lacking at this stage.^3,4

Why do some people take hCG with testosterone?

Testosterone replacement therapy (TRT) is used to boost testosterone levels in men with low levels. However, one concern with TRT is that it exerts “negative feedback” on the androgen receptors: suppressing the body's natural testosterone production, reducing testicular size, and interfering with sperm production.³ In some patients who start TRT, a drop in natural testosterone production may cause little to no sperm in the ejaculate within 10 weeks due to alterations of the hypothalamus-pituitary-gonadal (HPG) axis.⁵

This is where hCG therapy comes in - by mimicking the action of LH, hCG can help to maintain testicular function and preserve fertility in men treated with TRT. In men who received TRT with HCG (500 IU injection) every other day, for example, natural testosterone production increased by an average of 26%.⁶ Some studies have also found that sperm production is preserved after one year of co-administering a low-dose hCG alongside TRT.⁷  

Learn more about testosterone replacement therapy

Doctors may prescribe hCG to combat symptoms of conditions such as hypogonadism, in which the testes do not produce enough testosterone, sperm, or both.^8,9 The FDA has approved hCG injections in men for secondary hypogonadism. Interestingly, hCG is also indicated as part of a treatment plan for users of anabolic steroids who have lost their ability to produce their own testosterone.¹⁰

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Continue the conversation on the TRTed Community! 

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References:

1. Zenzmaier C, et al. Reprod Biol Endocrinol 2011;9:114.

2. Agarwal S, et al. Glob Pediatr Health2020;doi: 10.1177/2333794X20958980. eCollection 2020.

3. Danielle Betz, Kathleen Fane. Stat Pearls. Human Chorionic Gonadotropin 2022. Available at: https://www.ncbi.nlm.nih.gov/books/NBK532950/.

4. Stenman UH, et al. Clin Biochem 2004;37(7):549–61.

5. WHO Task Force. Lancet 1990;336(8721):955-9.

6. Coviello AD, et al. J Clin Endocrinol Metab 2005;90(5):2595–602.

7. Hsieh TC, et al. J Urol 2013;189(2):647–50.

8. Lee JA, Ramasamy R. Transl Androl Urol 2018;7(Suppl 3):S348–S352.

9. Medical News Today; available at: https://www.medicalnewstoday.com/articles/307634.  

10. Rahnema CD, et al. Fertil Steril 2014;101(5):1217–9.