Human Chorionic Gonadotropin (HCG) is known to be a protein hormone (or peptide hormone) that is produced naturally and endogenously in the female body by the syncytiotrophoblast cells of the placenta.
In females, HCG plays a very important role in promoting the secretion of progesterone, a hormone essential for pregnancy.
HCG for human use, packaged in vials, is not synthesized in nature but is derived from humans.
It is found in particularly high concentrations, as mentioned earlier, in pregnant women.
Because HCG exists in very high quantities only in women during pregnancy, it is in fact used as the primary sign of pregnancy in women.
HCG is the substance that home pregnancy test kits detect in urine, and if a significant amount is present, it is confirmed by a home pregnancy test kit.
In pregnant women, the increase of HCG in the body rises very rapidly and can be detected within 7 days after its secretion in the body increases.
However, at this time, HCG levels are just beginning to rise, and it takes about 2-3 months after pregnancy for plasma HCG levels to actually peak.
After 2-3 months, HCG levels begin to decrease.
While HCG itself can technically be considered synthetic Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH), in reality, HCG is actually a different hormone, but in males, it equally mimics the actions of both LH and FSH.
LH and FSH are gonadotropin hormones produced and secreted by the pituitary gland; in males, these two hormones signal the Leydig cells in the testes to initiate or increase the production of testosterone.
The term “Gonadotropin Hormone” refers to any compound or hormone that stimulates the gonadal organs (testes in men, ovaries in women).
In women, LH and FSH cause ovulation (the release of an egg from the ovary).
Because HCG essentially mimics LH and FSH in terms of physiological activity, it is used medically for the treatment of infertility in women with deficient endogenous gonadotropin secretion, and it is also prescribed for men for the treatment of hypogonadism (androgen production deficiency), delayed puberty, and conditions such as undescended testes (cryptorchidism).
On the other hand, bodybuilders and athletes utilize HCG in complex protocols lasting approximately 4-6 weeks to restore endogenous testosterone after concluding an anabolic steroid cycle, using it as part of their Post Cycle Therapy (PCT).
Human Chorionic Gonadotropin (HCG) was discovered in the 1920s when HCG extract from human placenta was administered to rabbits and its effects were observed[1].
Subsequently, in 1928, it was revealed that HCG is in fact the hormone essential for all roles related to pregnancy[2].
Shortly thereafter, the first HCG preparations, extracted from the pituitary glands of various animals, were developed and tested, and later in 1931, Organon began selling it on the prescription drug market under the name Pregnon.
Eventually, in 1932, this brand name was changed to Pregnyl, which became the universally recognized brand name for HCG.
Organon still manufactures, markets, and sells Pregnyl today, but not through pituitary extracts.
Eventually, with technological advances in the 1940s, it became possible to extract HCG from the urine of pregnant women through filtration and purification in laboratories, and by the 1960s, all HCG pharmaceutical manufacturers had adopted this method.
To this day, this method remains the way HCG is manufactured, and although other methods have been developed, extracting HCG from the urine of pregnant women remains the most effective, efficient, and cost-efficient method.
When HCG first began to be widely used in the medical field in the 1950s and 1960s, the medically approved indications for therapeutic use were very broad.
These included various medical indications such as the treatment of uterine excess bleeding, Fröhlich’s syndrome, cryptorchidism, female infertility, depression, male infertility, and hypogonadism.
Eventually, in the 1970s, when the FDA strengthened its control over the prescription drug market, the list of approved therapies was significantly reduced, and today HCG is used only for the treatment of male hypogonadism and cryptorchidism, and for female infertility.
Contrary to common rumor, HCG is not effective for fat loss, nor does it have the ability to stimulate the thyroid to produce more thyroid hormone.
It is particularly important to clarify this point because it stems from a 1954 study on obesity treatment where HCG was misused and misinterpreted for a long time.
This study claimed that subjects lost a significant amount of body fat after using HCG while maintaining an extremely low caloric intake (500 calories per day).
Many people misinterpreted this study, focusing solely on the fact that HCG was used without considering the caloric deficit of the subjects.
Over thirty years later, the entire study and the HCG-centered obesity treatment were re-evaluated, and its approved use for obesity treatment was revoked[3].
At the time, people were largely unaware that severe caloric restriction causes the body to lose vital lean mass (muscle) and organ tissue as it attempts to preserve itself, and that the consequences of a severe caloric deficit are worse for the body than obesity itself.
Eventually, in 1974, the FDA even issued a statement included in all pamphlets packaged with HCG, stating that using HCG for fat reduction is ineffective and should not be used as such.
Today, HCG is still widely used in the medical field, available under various major brand names (such as Organon’s Pregnyl, Serono’s Profasi, Ferring’s Novarel) in all markets worldwide, and numerous generic HCG products are also sold.
Chemical Properties of HCG
Human Chorionic Gonadotropin (HCG) is a protein (or peptide) hormone, but more specifically, it is referred to as an oligosaccharide glycoprotein (a glycoprotein with one or more carbohydrate/sugar molecules attached to the protein molecule).
Its protein structure consists of an amino acid chain of 244 amino acids and a subunit of 92 amino acids on top of it, which is 100% identical to LH and FSH.
It is precisely this subsection of the HCG molecule that allows it to mimic the actions of LH and FSH 100% identically at the same receptors on cells that LH and FSH activate.
Properties of HCG
The primary purpose of HCG is its use in female infertility treatment or to stimulate and/or increase endogenous testosterone production in males.
HCG is generally very well-tolerated by most men who use it for hormonal recovery after discontinuing an anabolic steroid cycle.
Especially because there have been many misconceptions about HCG since its introduction into the world of anabolic steroid use, there are two side effects of HCG that every individual must be aware of before using it.
HCG Side Effects
Estrogenic Side Effects
When using HCG, aromatase activity in the testes increases, converting androgens into estrogen, which can lead to elevated estrogen levels.
Consequently, the use of an Aromatase Inhibitor (AI) is essential during HCG use, with Aromasin (Exemestane) being the most suitable.
If other AIs like Letrozole or Arimidex are used, issues can arise with the common PCT protocol involving HCG, Nolvadex, and an AI.
If an AI is not used, estrogenic side effects such as water retention, bloating, increased blood pressure, increased fat storage, and gynecomastia can occur, which can interfere with the recovery of HPTA (Hypothalamic-Pituitary-Testicular Axis) function, counterproductively affecting the restoration of hormonal balance.
Therefore, the use of an AI during PCT is essential.
Androgenic Side Effects
When using HCG, the circulating plasma levels of testosterone and particularly Dihydrotestosterone (DHT) increase, which can lead to androgenic side effects.
This is an expected and desired effect of HCG.
The primary androgenic side effects include oily skin, acne breakouts, body and facial hair growth, Benign Prostatic Hyperplasia (BPH), and the potential triggering or worsening of Male Pattern Baldness (MPB).
In particular, Male Pattern Baldness affects those more significantly who possess the genetic predisposition for it.
HCG References
[1] Exogenous stimulation of corpus luteum formation in rabbits; Effect of human placenta, decidua, fetus, hydatid mole and corpus luteum extracts on the rabbit gonad. Hirose T 1920 J Jpn Gynecol Sot 16:1055.
[2] Die Schwangerschaftsdiagnose ausdem Ham durch Nachweis des Hypophysenvorderlappen-hormone.11. Pracktishe und theoretische Ergebnisse aus den hamuntersuchungen. Ascheim S/ Zondek B 1928 Klin Wochenschr 7:1453-1457.
[3] The effect of human chorionic gonadotropin (HCG) in the treatment of obesity by means of the Simeons therapy: A criteria-based meta-analysis. Lijesen GKS, et al. Br J Clin Pharmacol1995; 40: 237-43.
