Feedback - Customer Service and Feedback is very important to us, if for some reason you do not think you will be able to give all 5 stars in each feedback category, please contact us before leaving feedback.Please DO NOT leave negative or neutral feedback without contacting us. We are always willing to give you the best solution. A little respect of our hardwork would be much appreciated. Regarding the effect of use, due to various factors such as personal hair quality, the efficacy of the product varies from person to person and each consumer has different usage experience, so it is not guaranteed that everyone can achieve the same effect.