HCG 10000 IU injection contains human chorionic gonadotropin, a hormone that helps stimulate the body’s natural production of sex hormones. In men, it is often used to help treat certain cases of male infertility by stimulating the testes to produce testosterone and support sperm production. It may also be used in hormone therapy programs to help maintain hormonal balance. In women, HCG is commonly used in fertility treatments to trigger ovulation and support the development of eggs in the ovaries. Possible side effects may include headache, mood changes, mild swelling at the injection site, or hormonal fluctuations, and it should always be administered under proper medical supervision.