Well, I've never used it, but I want to whenever I get the money someday.
I do know a lot of people who use this and they say it works great for their cats!
You can just sprinkle a little on their food, or mix it in with their food, it's suppose to be completely tasteless and oderless (it's a powder). So your cats will never know their even eating it.Missing Link Vitamins
This has been said before recently, and I agree, that no one, us, pet owners, or the pet food companies know what is really a complete diet for our animals. No matter how high of a grade of food you feed, even if you feed a RAW/BARF diet, they could still be missing out on something, and the proper vitamins on a daily basis is great!
Just like humans, we try to eat right (well some of us) every single day, and there are also millions of us who take multivitamins every day! And I can garuntee you probably over 50% of what we eat daily is healthier and a better grade and what you will find in MOST petfoods, lol.
You can speak with your vet first, make sure your cat isn't allergic to anything specific (dietary related), I don't know of any vet that would object to a healthy or even unhealthy cat getting vitamins, unless there was an extra special circumstance.