cyclist2Bodybuilder
New member
Hi everyone,
I’d like to start by sharing a bit about my background to help clarify some misconceptions. I am a Registered Nurse (RN) and graduated from one of the top 20 nursing schools in the U.S. As part of my training, I studied Anatomy and Physiology in detail, including Pathophysiology, where we covered the endocrine system extensively. This message is meant to address some common misunderstandings about Human Chorionic Gonadotropin (HCG) in bodybuilding.
A lot of bodybuilders on forums believe that HCG creates a negative feedback loop in the male hypothalamic-pituitary-gonadal (HPG) axis. This is incorrect.
Here’s why:
HCG mimics Luteinizing Hormone (LH), but LH itself does not cause a negative feedback loop in the way that many think. The only hormones that create a negative feedback on the HPG axis are Testosterone, DHT, and Estrogens (specifically estradiol and estrone).
As shown in various studies, LH does not contribute to negative feedback loops—estrogens play a more significant role in this process. This is one reason why drugs like Nolvadex and Clomid are so effective in Post Cycle Therapy (PCT). They help to block estrogenic feedback, allowing the body to ramp up its natural testosterone production again.
Why AI (Aromatase Inhibitors) are needed:
Aromatase inhibitors like Aromasin are recommended during cycles because they prevent the conversion of testosterone to estrogen. When estrogen levels are too high, they create a negative feedback loop, which is why an AI is important to control this.
While Arimidex can also work well, it may cause a short-term "rebound" in estradiol levels once you stop using it, which could potentially cause issues if not managed carefully.
For further reading on these topics, here are some studies:
- [Study on HCG’s role in maintaining testosterone production](http://m.eje-online.org/content/155/4/513.short)
- [Study showing HCG helps preserve natural test production even with exogenous testosterone](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1478834/?page=1)
In conclusion:
To maintain natural testosterone production during and after a cycle, HCG, an AI (like Aromasin), and PCT drugs (such as Clomid and Nolvadex) work together effectively. However, if you only use HCG without an AI, it can cause estrogen buildup (via aromatization), which can lead to a negative feedback loop—but this is due to excess estrogen, not the HCG itself.
I also want to mention that cortisol control is an important factor during PCT. I’ll discuss this in a future post, as it’s something I’ve personally focused on during my PCT to minimize muscle loss. In my experience, cortisol management has helped me maintain most of my gains, with only minimal size loss (such as a slight decrease in bicep circumference).
After further discussion and research, I've learned that HCG does suppress LH production almost immediately, and chronic use of HCG can suppress FSH over time, as shown in the study linked below. While HCG doesn’t directly inhibit GnRH (the first step of the feedback loop), prolonged use can desensitize LH receptors, which may affect your PCT.
- [Study on HCG suppressing LH and FSH](http://www.ncbi.nlm.nih.gov/m/pubmed/19170708/)
- [Study on how prolonged HCG use can desensitize LH receptors](http://www.ncbi.nlm.nih.gov/m/pubmed/3084535/)
So, while HCG can be beneficial during a cycle for preserving testicular function, extended use could be counterproductive during PCT. For this reason, it’s often best to use HCG for a shorter period during PCT (around 4-5 weeks) to avoid receptor desensitization.
Final thoughts:
It’s up to you how you manage your cycle and PCT. But with the right approach, including HCG, AI, and Nolvadex/Clomid, you can better support your natural testosterone production post-cycle. Regardless of how you proceed, it’s important to keep in mind that any exogenous substances will impact your system, but proper management can minimize damage.
I’d like to start by sharing a bit about my background to help clarify some misconceptions. I am a Registered Nurse (RN) and graduated from one of the top 20 nursing schools in the U.S. As part of my training, I studied Anatomy and Physiology in detail, including Pathophysiology, where we covered the endocrine system extensively. This message is meant to address some common misunderstandings about Human Chorionic Gonadotropin (HCG) in bodybuilding.
A lot of bodybuilders on forums believe that HCG creates a negative feedback loop in the male hypothalamic-pituitary-gonadal (HPG) axis. This is incorrect.
Here’s why:
HCG mimics Luteinizing Hormone (LH), but LH itself does not cause a negative feedback loop in the way that many think. The only hormones that create a negative feedback on the HPG axis are Testosterone, DHT, and Estrogens (specifically estradiol and estrone).
As shown in various studies, LH does not contribute to negative feedback loops—estrogens play a more significant role in this process. This is one reason why drugs like Nolvadex and Clomid are so effective in Post Cycle Therapy (PCT). They help to block estrogenic feedback, allowing the body to ramp up its natural testosterone production again.
Why AI (Aromatase Inhibitors) are needed:
Aromatase inhibitors like Aromasin are recommended during cycles because they prevent the conversion of testosterone to estrogen. When estrogen levels are too high, they create a negative feedback loop, which is why an AI is important to control this.
While Arimidex can also work well, it may cause a short-term "rebound" in estradiol levels once you stop using it, which could potentially cause issues if not managed carefully.
For further reading on these topics, here are some studies:
- [Study on HCG’s role in maintaining testosterone production](http://m.eje-online.org/content/155/4/513.short)
- [Study showing HCG helps preserve natural test production even with exogenous testosterone](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1478834/?page=1)
In conclusion:
To maintain natural testosterone production during and after a cycle, HCG, an AI (like Aromasin), and PCT drugs (such as Clomid and Nolvadex) work together effectively. However, if you only use HCG without an AI, it can cause estrogen buildup (via aromatization), which can lead to a negative feedback loop—but this is due to excess estrogen, not the HCG itself.
I also want to mention that cortisol control is an important factor during PCT. I’ll discuss this in a future post, as it’s something I’ve personally focused on during my PCT to minimize muscle loss. In my experience, cortisol management has helped me maintain most of my gains, with only minimal size loss (such as a slight decrease in bicep circumference).
After further discussion and research, I've learned that HCG does suppress LH production almost immediately, and chronic use of HCG can suppress FSH over time, as shown in the study linked below. While HCG doesn’t directly inhibit GnRH (the first step of the feedback loop), prolonged use can desensitize LH receptors, which may affect your PCT.
- [Study on HCG suppressing LH and FSH](http://www.ncbi.nlm.nih.gov/m/pubmed/19170708/)
- [Study on how prolonged HCG use can desensitize LH receptors](http://www.ncbi.nlm.nih.gov/m/pubmed/3084535/)
So, while HCG can be beneficial during a cycle for preserving testicular function, extended use could be counterproductive during PCT. For this reason, it’s often best to use HCG for a shorter period during PCT (around 4-5 weeks) to avoid receptor desensitization.
Final thoughts:
It’s up to you how you manage your cycle and PCT. But with the right approach, including HCG, AI, and Nolvadex/Clomid, you can better support your natural testosterone production post-cycle. Regardless of how you proceed, it’s important to keep in mind that any exogenous substances will impact your system, but proper management can minimize damage.
