Kerastase Resistance Bain Extentioniste Shampoo

I always wait a couple months before I can honestly give a review for a beauty product that is this expensive. Preface: my hair is very long, thick and straight. I also have bayalage colors on the ends- so this also makes my hair somewhat dry/damaged. I wanted a product that would help strengthen the roots and also help with split ends. I have used Olaplex before this but I felt that Olaplex was not as effective anymore. Finally, I only wash my hair once a week. I did a lot of research on all of the available hair products that would my type of hair. I settled for Kerastase. I will also like to add: to make sure that this is effective for you, understand that their are companion products to this that make it work. Not only just the shampoo, but the conditioner and the hair serum afterwards (see photos). So develop a routine of using these 3 products and it will work. They all smell great (clean, almost cucumber smell) and they all are lightweight and don't weigh down my hair. My hair feels sleek and stronger compared to olaplex or store bought shampoo. CON: the size/amount of the shampoo. Since I have long hair, i use a lot of product. It lasted about two months. But again, I don't wash my hair everyday. Since this seems like a Euro-derived product, I will look at how much it is when I'm on that side of earth to see if it is cheaper. But I would recommend trying it.