Raspberry Ketones

I just started taking them. My teacher said he lost 3lbs. in 3 days. I know it is not enough time to make a real judgment . I have been working out 4 to 5 times a week and staying at least 500 cals. below my goal everyday. I still only lost about 5 to 10 lbs. in 6 months. I am willing to try anything that might give a little help.