Should i colon detox?

I am a 17 year old male, 6’0, 136 pounds. I’ve eaten a lot of junk/fried foods in my life and lately felt very sluggish and seem to always be tired. I have already been checked for limes disease so thats not it. My friend and i have already gone out and bought GNC’s Preventive Nutrition Cleanse and i’m beginning to feel that this could do more damage than it can do good for my body. What are the pro’s and cons of colon detox/cleansing for a boy my age, is it a good idea?