I didn't know to use the gold serum first, so the first week I did that with no visable difference.. At that point I went online and found more instructions. (not much instruction comes with the kit). So I tried to use the gold serum and nothing was coming out of it. I called and your customer service said they would send me a new tube. It never came so I called again and they ordered it again and I received it. I had originally ordered an extra set of serums so I started using that gold tube. I've been using it now for 21 days. I am starting to notice a difference but they certainly are NOT white. There have been times that I don't think anything is coming out of the tube. When I try it on my finger it is completely dry. So I try a different tube then a few days later I try the first one and it is working again. I really wanted white teeth now that I have had them straightened. I took care of my kids teeth before worrying about my own.