Hi! Have you looked at Purina's range of supplements? They have 5 different ones that focus on different things (mobility, skin and coat, natural defences, relaxation, and multivitamins). I tried the mobility one for my senior dog last year and I'm never going back. It helps support his joint health so he's been a lot more active during walks. I have a friend who tried the relaxation one for her anxious dog and it's done wonders for him too. He's a lot more chilled out and less reactive when people walk past the house. Other than that, I don't really give my dog supplements. Apart from chew sticks for his dental health :) Hope this helps!