Weight loss is short-term. Some research has linked HCG weight-loss products to a possible increase in cancer risk. HCG might encourage the production of androgen cells, which could result in the growth of certain types of cancers.
As a prescription medication, HCG is used mainly to treat fertility issues. HCG is not approved for over-the-counter use, nor has it been proved to work for weight loss.
The book "The Weight Loss Cure 'They' Don't Want You to Know About." was highly controversial. It's author, Kevin Trudeau, was banned from infomercials and was ordered by a federal court to pay five million dollars profits from his book.
He is currently in a federal prison for criminal contempt. He is obviously a highly untrustworthy figure, and as one of the main proponents of the hCG diet, this casts grave doubts on the diet's true effectiveness.