Just started using this product again. Have used this in the past and it works wonders. My skin feels tighter and has a smoother appearance after 1 bottle. I have used 3x 5x and 10x strength and I recommend starting at a lower concentration and working your way up. If you do not have sensitive skin you may want to start at 5x. This is a great product and you only have to apply it at nighttime. The smell is quite pleasant also in my opinion.