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.
Does take a little while to get into your system so I wouldn't judge it on the first few nights. If you take it most nights you're gonna have a better sleep.
I initially took it sporadically and it had a minor effect, I then read somewhere with Valerian it's recommend to be taken daily over a period of ~1 week to determine it's true effect. I did that and the difference was night and day.
Highly Recommend if you need that little bit extra to get to sleep and stay asleep so you wake up refreshed :)