To calculate the overall star rating and percentage breakdown by star, we do not use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyses reviews to verify trustworthiness.
This is a really effective at clearing yellowing hair colour. I bought it first on the Continent and was thrilled to find it on Amazon! it really does have a great effect. Don’t be put off by the really dark purple of the shampoo! I use it every 5 or 6 washes to keep my very pale blonde hair a beautiful silvery colour. I can recommend this product.