HCG (Human Chorionic Gonadotropin)

Human Chorionic Gonadotropin (hCG) is a luteinizing hormone (LH) analog. This means that it attaches to the LH receptors, mimicking it’s function. It has a much stronger binding affinity to the receptors than naturally occurring LH, which means that it will overcome any LH currently in the system. It has a mean (± SD) time to reach maximum serum concentration (t max) of 20.78 ± 9.68 h, and the half‐life (t ½) was 33.55 ± 4.14 h. For this reason, it is typically dosed 2-3 times weekly. For comparison, the half life of naturally occurring LH is 25-30 minutes. Dosing protocols vary, but studies show that weekly doses of hCG totaling 250-375IU/wk is enough to maintain ITT levels at 75% of normal, 93% of normal on 500-750IU/wk, and 126% of normal on 1500IU/wk. All doses tested were enough to maintain fertility and prevent testicular atrophy while on TRT. Interestingly, all studies on hCG have shown that loss of fertility and atrophy can be reversed even after years of solo TRT use. This means that hCG does not have to be used for the entirety of the time a man is on TRT. It can be added at any time with expected recovery of his baseline testicular function and fertility. hCG is known to aromatize at a higher rate than exogenous testosterone. The higher estradiol levels that can sometimes come with hCG use can lead to the following common side effects: • headache, depression; • feeling restless or irritable; • swelling; • breast tenderness or swelling; or • pain where the medicine was injected. In short: In the past, the thought was that luteinizing hormone was needed for testosterone production, and follicle stimulating hormone was needed for sperm production. Newer studies have proven that the most important aspect of fertility and sperm production is not FSH levels, but intratesticular testosterone (ITT) levels. Testosterone made outside of the testicles cannot enter the testicles, so the best way a man can maintain normal ITT levels (and therefore fertility) while on TRT is to add hCG. hCG is also used in assisting with recovery of testicular function in men who are stopping use of TRT or anabolic steroids. It has also been used as a monotherapy to raise natural testosterone levels in men who are unable to use TRT. Resources: Low-dose human chorionic gonadotropin maintains ITT in normal men with testosterone-induced hypogonadism: https://pubmed.ncbi.nlm.nih.gov/15713727/ Prevention of azoospermia and maintenance of fertility in hypogonadal men on TRT with low dose: https://pubmed.ncbi.nlm.nih.gov/23260550/ Low levels of hCG increase ITT concentrations and serum testosterone levels: https://pubmed.ncbi.nlm.nih.gov/20484472/