Amazon calculates a product’s star ratings using a machine learned model instead of a raw data average. The machine learned model takes into account factors including: the age of a review, helpfulness votes by customers and whether the reviews are from verified purchases.
I have medium/long thick straight hair and this product worked really well. You do have to use a fair amount and I always blow dried my hair before applying product. Would not recommend on wet hair as you'll just waste the product. Also noted that it comes off pretty easily with shampoo etc.