I may be missing something, but i cant find the half life of HCG. It is not listed on the regular half life tables.
I have found reports of 48 hours and up to 5-7 days but these studies were based on pregnant women.
What about injected HCG for our purposes? Anybody know?
Thanks
Here ya go! It's highlighted in the last paragraph.
DREi
Human Chorionic Gonadotropin, hCG (Pregnyl)
This information from Clinical Pharmacology 1.9
Description: Human chorionic gonadotropin (HCG) is a gonad-stimulating polypeptide hormone secreted by the placenta. It is obtained from the urine of pregnant women. The pharmacologic actions of HCG are similar to those of luteinizing hormone (LH) and is generally used as a substitute for LH. Human chorionic gonadotropin has been used to treat prepubertal cryptorchidism and hypogonadotropic hypogonadism in males, and in combination with menotropins or clomiphene to treat infertility in both males and females. Human chorionic gonadotropin was approved by the FDA in 1939.
Mechanism of Action: In females, human chorionic gonadotropin has actions essentially identical to those of luteinizing hormone (LH), however, HCG appears to have additional, though minimal, follicle-stimulating hormone (FSH) activity. The mechanism of action appears to be the same as for LH. By administering HCG after menotropins or clomiphene, the normal LH surge that precedes ovulation can be mimicked, thereby producing ovulation. Human chorionic gonadotropin also promotes the development and maintenance of the corpus luteum as well as stimulates ovarian cells to produce progesterone.
In males, HCG stimulates testosterone production in the Leydig cells and spermatogenesis in the seminiferous tubules. Stimulation of androgen production by HCG causes development of secondary sex characteristics in males with hypogonadotropic hypogonadism and stimulation of testicular descent in patients with prepubertal cryptorchidism not due to anatomical obstruction. Testicular descent is usually reversible after discontinuance of HCG therapy. Once initiated, it takes 70-80 days for germ cells to reach the spermatozoal stage.
Human chorionic gonadotropin has no known effects on appetite, or on mobilization or distribution of body fat.
Pharmacokinetics: Similar to other polypeptides, gonadotropins are almost completely degraded in the gastrointestinal tract; therefore, IM administration is required. Human chorionic gonadotropin primarily distributes into the testes and the ovaries. Serum concentrations of HCG are detectable after 2 hours. Peak concentrations are attained within 6 hours and persist for roughly 36 hours. The metabolic fate of HCG has not been elucidated.
The terminal half-life is approximately 23 hours. After a single IM injection, approximately 10-12% of the dose is excreted unchanged in the urine within 24 hours and can be detected for up to 3-4 days.