To calculate the overall star rating and percentage breakdown by star, we don’t 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.
Having suffered with cystitis for over a year and spent a fortune on products that don't work I was genuinely surprised that these do exactly as it says. My life is now greatly improved. I highly recommend them.