I got my first Kera Straight service done the end of November 2011. I had a colour service done the same visit before the Kera Straight was done. By mid December I noticed that my curls were coming back.. by January I contacted the salon that did the service and told them that after only 4-6 weeks it was wearing off. They had me come in to see and the girl who did my hair agreed that it was showing mostly on the ends that the product had worn off. I can tell you it wasn't just the ends. They offered to redo the service at a reduced cost at the 4 month mark. Where I live this service is very expensive ($350) and for it to wear off after such a short period of time I was totally dissatisfied with the product. At first I thought it wore off so quickly because they coloured my hair at the same time. Any other product I have used before I haven't been able to do colour at the same time or for at least a couple weeks afterwards. They have assured me that the colouring did not affect product and after reading some of the other posts it sounds like it just isn't a superior product. I refuse to pay again for a service they guaranteed me would last 4 months. I've had Keragreen done before and I will go back to having that done. I was very happy with the outcome of the Keragreen and I also wasn't forced into useing the KS shampoo and conditioner either. I was told I had to buy the shampoo and conditioner to guarantee the KS however there seems to be no guarantee at all...