I'm 21 5'5 145lbs I was wonder if I have to do 30 days or more?
I don't want to offend you Lynn but why are you trying HCG? Have you tried adjusting your diet and exercising?
You are a normal BMI. HCG, to me, seems really like a last-ditch resort. You are so young!! Why put something like that in your body?
Dittos what Silversword said, except I don't think it's a last resort, just quackery.
Are you willing to inject that stuff for the rest of your life? If not, find a method, or lifestyle really, that you can do for the rest of your life.
A lot of people in my area are doing the so called "hcg diet". Most of them are losing weight too. The thing is that they aren't even taking hcg. They are taking "homeopathic hcg drops", which by the very definition of homeopathic have absolutely no active ingredient. So it's really just a placebo. The reason that they are losing weight is because they are only eating 500 calories a day. Severe calorie restriction will work for anyone. Try it.
Here is a link that might be useful: HCG diet info