Before beginning the HCG diet, I did much research concerning the safety and effectiveness of the HCG diet. There are arguments for and against. Critics say that you will lose just as much weight on a Very Low Calorie Diet (VLCD) without the HCG as you will with, and that the HCG has no effect on weight loss. There is a much cited double blind study in which two groups followed a VLCD, one with a placebo and one with the HCG injections. In this study, both groups lost weight and there was no significant difference between the groups. However, this study only looked at weight loss.
I just finished reading a very interesting study which did a similar double blind study, but measured more than weight loss. It looked at BMI, loss of fat tissue, body circumference and irritability. In this study, there was a statisitically significant difference in the HCG group compared to the placebo group. The HCG group was found to lose more fat tissue and to be less irritable, although no difference was found in body measurements. It was an interesting article. You can read about it here.
At any rate, my own experience has been this...I have tried and failed many times to reduce the number of calories I ate and to increase my activity; in short, eat right and exercise. Before the HCG diet, this only led to increased hunger, frustration, and ultimately a depressing rebound in any weight I had lost. However, with the HCG, I had a couple days of irritiblilty at the beginning of phase 2, but overall there was very little hunger. I did not feel moody or frustrated at not being able to eat, in part because the pounds dropping off was very emotionally satisfying. The study showed, and it was true for me, that weight loss is a result of lost fat rather than lost muscle mass as in other VCLD protocols. There is just something about the way the HCG works on the hypothalamus in the brain. And, no study has shown any side effects from the use of HCG.
In my own UNscientific research, I found enough information to give this diet a try. I have seen it work for myself and for many others. They say that if something is too good to be true, it usually is, which is not bad advice. But, after 75 lbs. lost, I've decided that this diet really delivers. I am my own science project. If you are serious about losing weight and are willing to follow the protocol to a T, you will see the same results I have.
Do some science of your own! Let us know how your experiment turns out! I would love to share in your success!