Does the "Stay Calm" drops work for older cat meeting two need kitties?

I'm introducing two new kitties into my home tomorrow and I have a 9 year old male cat who doesn't react well to change. I just found out about the "Stay calm" drops for cats to help keep them mellow. Has anyone tried this for travel or stress for their cat? Did it help? What was the outcome? How did your cat react?

Thank you in advance!