When most people hear human Chorionic Gonadotropin (hCG), they immediately think of a positive pregnancy test. While it is famously dubbed the "pregnancy hormone," this complex glycoprotein has a fascinating physiological footprint that extends far beyond the pharmacy test strip.

The Anchor of Early Pregnancy

Produced by the syncytiotrophoblast cells (the precursor to the placenta) almost immediately after a fertilized egg implants in the uterine wall, hCG acts as the primary chemical messenger of early gestation.

Its main mandate? Rescue the corpus luteum. Under normal circumstances, the corpus luteum (the remnant of the ovarian follicle after ovulation) degenerates at the end of the menstrual cycle, causing progesterone levels to plunge and triggering menstruation. hCG halts this breakdown, signaling the corpus luteum to continuously churn out progesterone. This sustains a thick, nutrient-rich endometrial lining, securing the embryo until the placenta can take over hormone production around the end of the first trimester.

hCG and TRT: Why is hCG often included in a TRT protocol?

Human Chorionic Gonadotropin, abbreviated as hCG, is a naturally occurring hormone found in both men and women. hCG performs many different functions throughout the body.

hCG for men mimics the effects of Luteinizing Hormone (LH), which stimulates the testicles to release testosterone. hCG can be supplemented for many different reasons, including as a treatment for hypogonadism and low sperm count.

For men on Testosterone Replacement Therapy (TRT), hCG injections are often prescribed to combat the testicular shrinkage that can occur as a result of a TRT protocol. In this way, TRT and hCG injections can work together to provide a synergistic treatment plan.

The reason men on TRT can experience testicular atrophy is because the body recognizes that it’s receiving testosterone from an external source, so it shuts down its own natural production. This is a normal biological reaction that occurs with many different medications and supplements. When the testes stop producing testosterone, they typically go dormant, which can lead to testicular shrinkage and testicular atrophy.

When you supplement with the hCG hormone, the testes are stimulated to continue producing testosterone, which means they do not go dormant.

This is also helpful if you ever plan to stop your TRT protocol, because your testes will still be active and producing testosterone (though you will likely experience a return of the low-T symptoms that made you start TRT in the first place).