Yes, this product really works. No, it doesn't work overnight. However, after only a week, my little Luna's fur (pug/terrier/troll doll mix) starting growing in as white as could be! Luna is a fussy eater, but she loved the taste of this sprinkled on her food. It is a bit pricey (When purchased at my groomer's, it was $24.95 for a 30 gram bottle.), and we went through the bottle quite quickly. Just when we started seeing results, the bottle was empty. Interesting note: I went to purchase this product at my local PetSmart and was informed that they had just received a shipment but took it off the shelves? Why? Because Angels' Eyes has not yet been approved by the FDA. Thank goodness I can still find it on Amazon.com.