Both gonadorelin and HCG are gonadotropin-releasing hormone (GnRH) receptor agonists. HCG is a natural compound produced by the placenta and created commercially using recombinant genetic techniques (though it was once harvested from the placentas of animals). Gonadorelin is a synthetic peptide produced using biochemical techniques. While these two compounds have similar effects because they act on the same receptor, they are not identical. Research indicates that gonadorelin may have an extended spectrum of beneficial effects while being easier to store. Below is a look at these two compounds, their uses, and their differences.
HCG is a heterodimer, which means it is made up of two different proteins that are “stuck” together. The alpha subunit of HCG is like luteinizing and follicle-stimulating hormones. The beta subunit is like luteinizing hormone and appears to be the active component of HCG.
Gonadorelin is just 10 amino acids in length and weighs just 1182 g/mol. It is a synthetic GnRH analogue and stimulates the pituitary gland to release luteinizing hormone, follicle-stimulating hormone (FSH) and, (to a lesser extent) thyroid stimulating hormone. It has been researched for use in treating infertility, menstrual cycle irregularities, and hypogonadism. It is also of active interest for its potential use in breast and prostate cancers as well as Alzheimer’s disease.
It is important to note that FSH does not increase testosterone production. Rather, it increases the numbers of androgen-binding proteins in the testes, which increases local concentrations of androgen by sequestering it from the systemic circulation. The result is a local increase in the concentration of testosterone in the testicles and increased sperm production. Increasing levels of FSH, in both men and women, helps to improve fertility by increasing rates of sperm and egg production. It does not, however, cause a systemic increase in any sex hormones.
Of note, increasing production of LH, and thus testosterone, with either of these compounds is a matter of dosage. Using too much of either gonadorelin or HCG will result in suppression of LH and testosterone production because it will stimulate the body’s natural negative feedback loop. Thus, only low doses of either of these compounds is useful in stimulating testosterone production.
Higher levels of testosterone are thought to preserve cognitive function. Until recently, however, increased levels of LH were associated with increases in neurocognitive pathology. The research seemed to favor the benefit of testosterone even if LH levels are increased, showing an overall increase in cognitive function when both hormones were elevated. Testing, however, is ongoing with interest in understanding how gonadorelin might be used in an orchestrated manner to help promote long-term cognitive health[2]. More specifically, recent research has indicated that GnRH agonists, like gonadorelin, may increase interconnectivity between the right and left hemispheres of the brain. The net effect is an increase in cognitive function, particularly where vision and memory are concerned[3]. This suggests that doubts about earlier research were correct and that, overall, GnRH agonists likely improve cognitive function. Of course, this will spur additional research on this topic.
Gonadorelin is used in the same ways as discussed for HCG above but has also been tested in additional applications. Research suggests that gonadorelin may be useful in slowing cancer growth in cancers in which cell division is, at least in part, stimulated by estrogen or testosterone levels. This is particularly true of certain forms of breast cancer. In fact, research suggests that gonadorelin may even be useful as a breast cancer preventative, reducing the risk by as much as 50% if utilized over a 10-year period[4].
In the setting of prostate cancer, high levels of gonadorelin are used to shut off testosterone production and can thus help to slow the growth of aggressive prostate cancers. Note that while low levels of gonadorelin increase testosterone production, high levels shut it down by stimulating natural negative feedback mechanisms.
[2] A. Cáceres, J. E. Vargas, and J. R. González, “APOE and MS4A6A interact with GnRH signaling in Alzheimer’s disease: Enrichment of epistatic effects,” Alzheimers Dement. J. Alzheimers Assoc., vol. 13, no. 4, pp. 493–497, Apr. 2017, doi: 10.1016/j.jalz.2016.05.009.
[3] T. Chen et al., “Influence of Gonadotropin Hormone Releasing Hormone Agonists on Interhemispheric Functional Connectivity in Girls With Idiopathic Central Precocious Puberty,” Front. Neurol., vol. 11, p. 17, Jan. 2020, doi: 10.3389/fneur.2020.00017.
[4] “Sex steroids and breast cancer prevention. - Abstract - Europe PMC.” https://europepmc.org/article/med/7999456 (accessed Jul. 10, 2022).
Gonadorelin vs HCG
Human chorionic gonadotropin (HCG) is a massive peptide made up of 237 amino acids and possessing a molecular weight of 36,700 g/mol. HCG is commonly measured in either blood or urine as a way of detecting pregnancy given its production by trophoblast cells in the placenta. It can also serve as a marker for diagnosing and tracking certain types of tumors. Some research shows that HCG effectively induces weight loss, primarily by affecting fat tissue. This claim, however, has been difficult to substantiate as results vary between individuals. In general, HCG is not recommended for inducing weight loss[1].HCG is a heterodimer, which means it is made up of two different proteins that are “stuck” together. The alpha subunit of HCG is like luteinizing and follicle-stimulating hormones. The beta subunit is like luteinizing hormone and appears to be the active component of HCG.
Gonadorelin is just 10 amino acids in length and weighs just 1182 g/mol. It is a synthetic GnRH analogue and stimulates the pituitary gland to release luteinizing hormone, follicle-stimulating hormone (FSH) and, (to a lesser extent) thyroid stimulating hormone. It has been researched for use in treating infertility, menstrual cycle irregularities, and hypogonadism. It is also of active interest for its potential use in breast and prostate cancers as well as Alzheimer’s disease.
Gonadorelin vs HCG: Testosterone Production
Both gonadorelin and HCG can increase levels of testosterone. They do this by stimulating the release of luteinizing hormone (LH), which stimulates the testes and ovaries to produce steroid hormones. In men, this leads to a marked increase in the production of testosterone. In women it also leads to increased testosterone levels, but this effect is overshadowed by a much larger increase in estrogen levels. Both compounds also stimulate the release of FSH, which works together with LH to promote the production of sperm and eggs in the testes and ovaries respectively.It is important to note that FSH does not increase testosterone production. Rather, it increases the numbers of androgen-binding proteins in the testes, which increases local concentrations of androgen by sequestering it from the systemic circulation. The result is a local increase in the concentration of testosterone in the testicles and increased sperm production. Increasing levels of FSH, in both men and women, helps to improve fertility by increasing rates of sperm and egg production. It does not, however, cause a systemic increase in any sex hormones.
Of note, increasing production of LH, and thus testosterone, with either of these compounds is a matter of dosage. Using too much of either gonadorelin or HCG will result in suppression of LH and testosterone production because it will stimulate the body’s natural negative feedback loop. Thus, only low doses of either of these compounds is useful in stimulating testosterone production.
Higher levels of testosterone are thought to preserve cognitive function. Until recently, however, increased levels of LH were associated with increases in neurocognitive pathology. The research seemed to favor the benefit of testosterone even if LH levels are increased, showing an overall increase in cognitive function when both hormones were elevated. Testing, however, is ongoing with interest in understanding how gonadorelin might be used in an orchestrated manner to help promote long-term cognitive health[2]. More specifically, recent research has indicated that GnRH agonists, like gonadorelin, may increase interconnectivity between the right and left hemispheres of the brain. The net effect is an increase in cognitive function, particularly where vision and memory are concerned[3]. This suggests that doubts about earlier research were correct and that, overall, GnRH agonists likely improve cognitive function. Of course, this will spur additional research on this topic.
Gonadorelin vs HCG: Research Uses
The uses of HCG are relatively limited. It is primarily of use in testing where it can serve to diagnosis and track both pregnancy and certain tumors associated with the reproductive system. HCG is used extensively in women to stimulate natural ovulation and thus promote fertility. In this setting, it is often useful in the setting of hypogonadism caused by polycystic ovarian syndrome. HCG can also be used in men to stimulate fertility. It is often used in conjunction with testosterone treatment to prevent testicular atrophy.Gonadorelin is used in the same ways as discussed for HCG above but has also been tested in additional applications. Research suggests that gonadorelin may be useful in slowing cancer growth in cancers in which cell division is, at least in part, stimulated by estrogen or testosterone levels. This is particularly true of certain forms of breast cancer. In fact, research suggests that gonadorelin may even be useful as a breast cancer preventative, reducing the risk by as much as 50% if utilized over a 10-year period[4].
In the setting of prostate cancer, high levels of gonadorelin are used to shut off testosterone production and can thus help to slow the growth of aggressive prostate cancers. Note that while low levels of gonadorelin increase testosterone production, high levels shut it down by stimulating natural negative feedback mechanisms.
Gonadorelin vs HCG: Storage and Reconstitution
Storage differs dramatically between these two compounds. While HCG must always be stored in a refrigerator (both before and after reconstitution), gonadorelin can be stored at room temperature. Both peptides, however, can be reconstituted (mixing of peptides with a solvent for injection) with water and do not require alcohol or special compounds for dissolution. It is important to note that water is not naturally bacteriostatic, like alcohol for instance, and thus specially treated and prepared water solutions should be used to reconstitute these peptides in order to avoid contamination, bacterial growth, fungal growth, etc.Gonadorelin vs HCG: The Bottom Line
While gonadorelin and HCG are similar in many ways, they are not identical. Gonadorelin is a simpler peptide with few side effects and simpler storage requirements. While HCG is primarily used for testing purposes and in a limited number of therapeutic settings, research suggests that gonadorelin has a wider range of potential therapeutic actions.Resources
[1] H. Yamasaki, T. Douchi, S. Yamamoto, T. Oki, R. Kuwahata, and Y. Nagata, “Body fat distribution and body composition during GnRH agonist therapy,” Obstet. Gynecol., vol. 97, no. 3, pp. 338–342, Mar. 2001, doi: 10.1016/s0029-7844(00)01181-9.[2] A. Cáceres, J. E. Vargas, and J. R. González, “APOE and MS4A6A interact with GnRH signaling in Alzheimer’s disease: Enrichment of epistatic effects,” Alzheimers Dement. J. Alzheimers Assoc., vol. 13, no. 4, pp. 493–497, Apr. 2017, doi: 10.1016/j.jalz.2016.05.009.
[3] T. Chen et al., “Influence of Gonadotropin Hormone Releasing Hormone Agonists on Interhemispheric Functional Connectivity in Girls With Idiopathic Central Precocious Puberty,” Front. Neurol., vol. 11, p. 17, Jan. 2020, doi: 10.3389/fneur.2020.00017.
[4] “Sex steroids and breast cancer prevention. - Abstract - Europe PMC.” https://europepmc.org/article/med/7999456 (accessed Jul. 10, 2022).
