I haven't been using them long enough to notice any difference.

Right now I decided to try another type of plugin called Pet-Ease Pheromone Plus and it's by Nutri Vet. It contains extracts of Valerian Root, St. John's Wart, Lavender, and Natural Feline Pheromone Extract. I also bought the spray and it smells so much nicer than the Feliway spray. I bought it at Petsmart and it's cheaper than the Feliway is there. They also sell it online and I think I could buy it for a bit less.

I've also been spraying Starr with an herbal spray to help reduce his stress. It was made by his holistic vet and it also contains Valerian but I think that she used the flower. I spray him one time in the morning and one time in the evening. He hates the sound of the spray but I think it's been helping him.