Yes, it works if you stick with the program. There are probably some forms of it that are a scam, but the real stuff works. I did it for 4 weeks on an 800 calorie/day diet and lost 15 pounds. That doesn't sound all that much, but it was good for me. I'm a fraidy cat when it comes to shots, but the injections are a breeze with the short and thin needles. Some people inject into their muscle, but it seems that more opt for the short insulin needles and inject into their fat layer and it still works.
The HCG assists your body in burning fat for energy so you're less hungry on the low calorie diet. Look up "Pounds and Inches" for the original protocol.