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.
It has become an important part of my skin care regime. I had a few bald patches in my brows and 15 days of daily use and really helped with that. Additional advantage includes longer and fuller brows and lashes. Totally recommended. Update: Just bought another bottle of this. Because I absolutely loveeeee it.